Move test units to z80/tests, and drivers are now statically linked

Makefiles for the test units were getting messier, so now drivers
(that need to be tested) are statically compiled in their own
folder under z80/drivers.

The kernel makefile and is now broken since everything has been moved.

61 files changed, 907 insertions, 1148 deletions

diff --git a/sw/z80/coding_rules.txt b/doc/coding_rules.txt
index e5c11f0..e5c11f0 100644
--- a/sw/z80/coding_rules.txt
+++ b/doc/coding_rules.txt
diff --git a/sw/programmer/linux/src/flash.c b/sw/programmer/linux/src/flash.c
index 6fcd09f..24d5269 100644
--- a/sw/programmer/linux/src/flash.c
+++ b/sw/programmer/linux/src/flash.c
@@ -32,7 +32,7 @@ int flash_write(const char *romfile, void (*log)(const char *))
             log("[!] Error while reading from file\n");
             break;
         }
-                
+
 		head.addr = (uint16_t) lseek(romfd, 0, SEEK_CUR);
 
 		written = write(flash_serial_fd, &head, sizeof(struct flash_blk));
diff --git a/sw/z80/TODO.txt b/sw/z80/TODO.txt
new file mode 100644
index 0000000..67be671
--- /dev/null
+++ b/sw/z80/TODO.txt
@@ -0,0 +1 @@
+- fix kernel makefile (currently broken)
diff --git a/sw/z80_tests/usart/devices.h b/sw/z80/arch/addresses.h
index a846f9b..07ab473 100644
--- a/sw/z80_tests/usart/devices.h
+++ b/sw/z80/arch/addresses.h
@@ -1,5 +1,5 @@
-#ifndef __DEVICES_H__
-#define __DEVICES_H__
+#ifndef __ADDRESSES_H__
+#define __ADDRESSES_H__
 
 #define ADDR_DEV_ROM_L      0x0000
 #define ADDR_DEV_ROM_H      0x2000
diff --git a/sw/z80/crt0.rel b/sw/z80/crt0.rel
deleted file mode 100644
index 880fd57..0000000
--- a/sw/z80/crt0.rel
+++ /dev/null
@@ -1,86 +0,0 @@
-XL2
-H 14 areas 5 global symbols
-M crt0
-S .__.ABS. Def0000
-S _kmain Ref0000
-A _CODE size A flags 0 addr 0
-S __clock Def0000
-S _exit Def0004
-A _HEADER size 0 flags 8 addr 0
-A _HEADER0 size 3 flags 8 addr 0
-A _HEADER1 size 2 flags 8 addr 8
-A _HEADER2 size 2 flags 8 addr 10
-A _HEADER3 size 2 flags 8 addr 18
-A _HEADER4 size 2 flags 8 addr 20
-A _HEADER5 size 2 flags 8 addr 28
-A _HEADER6 size 2 flags 8 addr 30
-A _HEADER7 size 2 flags 8 addr 38
-A _HEADER8 size C flags 8 addr 100
-A _HOME size 0 flags 0 addr 0
-A _INITIALIZER size 0 flags 0 addr 0
-A _GSINIT size 6 flags 0 addr 0
-S gsinit Def0000
-A _GSFINAL size 1 flags 0 addr 0
-A _DATA size 0 flags 0 addr 0
-A _INITIALIZED size 0 flags 0 addr 0
-A _BSEG size 0 flags 0 addr 0
-A _BSS size 0 flags 0 addr 0
-A _HEAP size 0 flags 0 addr 0
-T 00 00
-R 00 00 02 00
-T 00 00 C3 00 01
-R 00 00 02 00 00 03 0A 00
-T 08 00
-R 00 00 03 00
-T 08 00 ED 4D
-R 00 00 03 00
-T 10 00
-R 00 00 04 00
-T 10 00 ED 4D
-R 00 00 04 00
-T 18 00
-R 00 00 05 00
-T 18 00 ED 4D
-R 00 00 05 00
-T 20 00
-R 00 00 06 00
-T 20 00 ED 4D
-R 00 00 06 00
-T 28 00
-R 00 00 07 00
-T 28 00 ED 4D
-R 00 00 07 00
-T 30 00
-R 00 00 08 00
-T 30 00 ED 4D
-R 00 00 08 00
-T 38 00
-R 00 00 09 00
-T 38 00 ED 4D
-R 00 00 09 00
-T 00 01
-R 00 00 0A 00
-T 00 01
-R 00 00 0A 00
-T 00 01 31 FF FF CD 00 00 CD 00 00 C3 04 00
-R 00 00 0A 00 00 06 0D 00 02 09 01 00 00 0C 00 00
-T 00 00
-R 00 00 00 00
-T 00 00 3E 02 CF C9
-R 00 00 00 00
-T 04 00
-R 00 00 00 00
-T 04 00 3E 00 CF
-R 00 00 00 00
-T 07 00
-R 00 00 00 00
-T 07 00 76 18 FD
-R 00 00 00 00
-T 00 00
-R 00 00 0D 00
-T 00 00 78 B1 28 02 ED B0
-R 00 00 0D 00
-T 06 00
-R 00 00 0D 00
-T 00 00 C9
-R 00 00 0E 00
diff --git a/sw/z80_tests/usart/build/ctc.asm b/sw/z80/drivers/build/ctc.asm
index 838756a..838756a 100644
--- a/sw/z80_tests/usart/build/ctc.asm
+++ b/sw/z80/drivers/build/ctc.asm
diff --git a/sw/z80_tests/usart/build/ctc.lst b/sw/z80/drivers/build/ctc.lst
index e758d8a..e758d8a 100644
--- a/sw/z80_tests/usart/build/ctc.lst
+++ b/sw/z80/drivers/build/ctc.lst
diff --git a/sw/z80_tests/usart/build/ctc.rel b/sw/z80/drivers/build/ctc.rel
index 50a8b42..50a8b42 100644
--- a/sw/z80_tests/usart/build/ctc.rel
+++ b/sw/z80/drivers/build/ctc.rel
diff --git a/sw/z80_tests/usart/build/ctc.sym b/sw/z80/drivers/build/ctc.sym
index 82ca00e..82ca00e 100644
--- a/sw/z80_tests/usart/build/ctc.sym
+++ b/sw/z80/drivers/build/ctc.sym
diff --git a/sw/z80_tests/usart/build/pio.asm b/sw/z80/drivers/build/pio.asm
index ee1fcc6..3045492 100644
--- a/sw/z80_tests/usart/build/pio.asm
+++ b/sw/z80/drivers/build/pio.asm
@@ -13,6 +13,8 @@
 	.globl _pio_set_mode
 	.globl _pio_set_interrupts
 	.globl _pio_set_interrupts_mask
+	.globl _pio_read
+	.globl _pio_write
 ;--------------------------------------------------------
 ; special function registers
 ;--------------------------------------------------------
@@ -185,6 +187,44 @@ _pio_set_interrupts_mask::
 	ld	(hl),c
 ;pio.c:39: _pio_control(port, mask);
 	ret
+;pio.c:42: uint8_t pio_read(int port)
+;	---------------------------------
+; Function pio_read
+; ---------------------------------
+_pio_read::
+;pio.c:44: return *(pio_port + port);
+	ld	hl,#2
+	add	hl,sp
+	ld	iy,#_pio_port
+	ld	a,0 (iy)
+	add	a, (hl)
+	ld	c,a
+	ld	a,1 (iy)
+	inc	hl
+	adc	a, (hl)
+	ld	b,a
+	ld	a,(bc)
+	ld	l,a
+	ret
+;pio.c:47: void pio_write(int port, uint8_t data)
+;	---------------------------------
+; Function pio_write
+; ---------------------------------
+_pio_write::
+;pio.c:49: _pio_data(port, data);
+	ld	hl, #4+0
+	add	hl, sp
+	ld	c, (hl)
+	pop	de
+	pop	hl
+	push	hl
+	push	de
+;pio.c:8: *(pio_port + port) = data;
+	ld	de,(_pio_port)
+	add	hl,de
+	ld	(hl),c
+;pio.c:49: _pio_data(port, data);
+	ret
 	.area _CODE
 	.area _INITIALIZER
 __xinit__pio_port:
diff --git a/sw/z80/drivers/build/pio.lst b/sw/z80/drivers/build/pio.lst
new file mode 100644
index 0000000..0b83616
--- /dev/null
+++ b/sw/z80/drivers/build/pio.lst
@@ -0,0 +1,234 @@
+                              1 ;--------------------------------------------------------
+                              2 ; File Created by SDCC : free open source ANSI-C Compiler
+                              3 ; Version 3.6.0 #9615 (Linux)
+                              4 ;--------------------------------------------------------
+                              5 	.module pio
+                              6 	.optsdcc -mz80
+                              7 	
+                              8 ;--------------------------------------------------------
+                              9 ; Public variables in this module
+                             10 ;--------------------------------------------------------
+                             11 	.globl __pio_data
+                             12 	.globl __pio_control
+                             13 	.globl _pio_set_mode
+                             14 	.globl _pio_set_interrupts
+                             15 	.globl _pio_set_interrupts_mask
+                             16 	.globl _pio_read
+                             17 	.globl _pio_write
+                             18 ;--------------------------------------------------------
+                             19 ; special function registers
+                             20 ;--------------------------------------------------------
+                             21 ;--------------------------------------------------------
+                             22 ; ram data
+                             23 ;--------------------------------------------------------
+                             24 	.area _DATA
+                             25 ;--------------------------------------------------------
+                             26 ; ram data
+                             27 ;--------------------------------------------------------
+                             28 	.area _INITIALIZED
+   0000                      29 _pio_port:
+   0000                      30 	.ds 2
+   0002                      31 _pio_ctrl:
+   0002                      32 	.ds 2
+                             33 ;--------------------------------------------------------
+                             34 ; absolute external ram data
+                             35 ;--------------------------------------------------------
+                             36 	.area _DABS (ABS)
+                             37 ;--------------------------------------------------------
+                             38 ; global & static initialisations
+                             39 ;--------------------------------------------------------
+                             40 	.area _HOME
+                             41 	.area _GSINIT
+                             42 	.area _GSFINAL
+                             43 	.area _GSINIT
+                             44 ;--------------------------------------------------------
+                             45 ; Home
+                             46 ;--------------------------------------------------------
+                             47 	.area _HOME
+                             48 	.area _HOME
+                             49 ;--------------------------------------------------------
+                             50 ; code
+                             51 ;--------------------------------------------------------
+                             52 	.area _CODE
+                             53 ;pio.c:6: inline void _pio_data(int port, uint8_t data)
+                             54 ;	---------------------------------
+                             55 ; Function _pio_data
+                             56 ; ---------------------------------
+   0000                      57 __pio_data::
+                             58 ;pio.c:8: *(pio_port + port) = data;
+   0000 21 02 00      [10]   59 	ld	hl,#2
+   0003 39            [11]   60 	add	hl,sp
+   0004 FD 21r00r00   [14]   61 	ld	iy,#_pio_port
+   0008 FD 7E 00      [19]   62 	ld	a,0 (iy)
+   000B 86            [ 7]   63 	add	a, (hl)
+   000C 4F            [ 4]   64 	ld	c,a
+   000D FD 7E 01      [19]   65 	ld	a,1 (iy)
+   0010 23            [ 6]   66 	inc	hl
+   0011 8E            [ 7]   67 	adc	a, (hl)
+   0012 47            [ 4]   68 	ld	b,a
+   0013 21 04 00      [10]   69 	ld	hl, #4+0
+   0016 39            [11]   70 	add	hl, sp
+   0017 7E            [ 7]   71 	ld	a, (hl)
+   0018 02            [ 7]   72 	ld	(bc),a
+   0019 C9            [10]   73 	ret
+                             74 ;pio.c:11: inline void _pio_control(int port, uint8_t cmd)
+                             75 ;	---------------------------------
+                             76 ; Function _pio_control
+                             77 ; ---------------------------------
+   001A                      78 __pio_control::
+                             79 ;pio.c:13: *(pio_ctrl + port) = cmd;
+   001A 21 02 00      [10]   80 	ld	hl,#2
+   001D 39            [11]   81 	add	hl,sp
+   001E FD 21r02r00   [14]   82 	ld	iy,#_pio_ctrl
+   0022 FD 7E 00      [19]   83 	ld	a,0 (iy)
+   0025 86            [ 7]   84 	add	a, (hl)
+   0026 4F            [ 4]   85 	ld	c,a
+   0027 FD 7E 01      [19]   86 	ld	a,1 (iy)
+   002A 23            [ 6]   87 	inc	hl
+   002B 8E            [ 7]   88 	adc	a, (hl)
+   002C 47            [ 4]   89 	ld	b,a
+   002D 21 04 00      [10]   90 	ld	hl, #4+0
+   0030 39            [11]   91 	add	hl, sp
+   0031 7E            [ 7]   92 	ld	a, (hl)
+   0032 02            [ 7]   93 	ld	(bc),a
+   0033 C9            [10]   94 	ret
+                             95 ;pio.c:16: void pio_set_mode(int port, int mode, uint8_t io)
+                             96 ;	---------------------------------
+                             97 ; Function pio_set_mode
+                             98 ; ---------------------------------
+   0034                      99 _pio_set_mode::
+                            100 ;pio.c:19: _pio_control(port, ((mode << 6) | 0x0F));
+   0034 21 04 00      [10]  101 	ld	hl, #4+0
+   0037 39            [11]  102 	add	hl, sp
+   0038 7E            [ 7]  103 	ld	a, (hl)
+   0039 0F            [ 4]  104 	rrca
+   003A 0F            [ 4]  105 	rrca
+   003B E6 C0         [ 7]  106 	and	a,#0xc0
+   003D F6 0F         [ 7]  107 	or	a, #0x0f
+   003F 4F            [ 4]  108 	ld	c,a
+   0040 D1            [10]  109 	pop	de
+   0041 E1            [10]  110 	pop	hl
+   0042 E5            [11]  111 	push	hl
+   0043 D5            [11]  112 	push	de
+                            113 ;pio.c:13: *(pio_ctrl + port) = cmd;
+   0044 FD 2Ar02r00   [20]  114 	ld	iy,(_pio_ctrl)
+   0048 5D            [ 4]  115 	ld	e, l
+   0049 54            [ 4]  116 	ld	d, h
+   004A FD 19         [15]  117 	add	iy, de
+   004C FD 71 00      [19]  118 	ld	0 (iy), c
+                            119 ;pio.c:23: if (mode == PIO_MODE_BIT_IO) {
+   004F FD 21 04 00   [14]  120 	ld	iy,#4
+   0053 FD 39         [15]  121 	add	iy,sp
+   0055 FD 7E 00      [19]  122 	ld	a,0 (iy)
+   0058 D6 03         [ 7]  123 	sub	a, #0x03
+   005A C0            [11]  124 	ret	NZ
+   005B FD 7E 01      [19]  125 	ld	a,1 (iy)
+   005E B7            [ 4]  126 	or	a, a
+   005F C0            [11]  127 	ret	NZ
+                            128 ;pio.c:24: _pio_control(port, io);
+   0060 FD 21 06 00   [14]  129 	ld	iy,#6
+   0064 FD 39         [15]  130 	add	iy,sp
+   0066 FD 4E 00      [19]  131 	ld	c,0 (iy)
+                            132 ;pio.c:13: *(pio_ctrl + port) = cmd;
+   0069 ED 5Br02r00   [20]  133 	ld	de,(_pio_ctrl)
+   006D 19            [11]  134 	add	hl,de
+   006E 71            [ 7]  135 	ld	(hl),c
+                            136 ;pio.c:24: _pio_control(port, io);
+   006F C9            [10]  137 	ret
+                            138 ;pio.c:28: void pio_set_interrupts(int port, int control)
+                            139 ;	---------------------------------
+                            140 ; Function pio_set_interrupts
+                            141 ; ---------------------------------
+   0070                     142 _pio_set_interrupts::
+                            143 ;pio.c:31: _pio_control(port, (control | 0x07));
+   0070 21 04 00      [10]  144 	ld	hl, #4+0
+   0073 39            [11]  145 	add	hl, sp
+   0074 7E            [ 7]  146 	ld	a, (hl)
+   0075 F6 07         [ 7]  147 	or	a, #0x07
+   0077 4F            [ 4]  148 	ld	c,a
+   0078 D1            [10]  149 	pop	de
+   0079 E1            [10]  150 	pop	hl
+   007A E5            [11]  151 	push	hl
+   007B D5            [11]  152 	push	de
+                            153 ;pio.c:13: *(pio_ctrl + port) = cmd;
+   007C ED 5Br02r00   [20]  154 	ld	de,(_pio_ctrl)
+   0080 19            [11]  155 	add	hl,de
+   0081 71            [ 7]  156 	ld	(hl),c
+                            157 ;pio.c:31: _pio_control(port, (control | 0x07));
+   0082 C9            [10]  158 	ret
+                            159 ;pio.c:34: void pio_set_interrupts_mask(int port, int control, uint8_t mask)
+                            160 ;	---------------------------------
+                            161 ; Function pio_set_interrupts_mask
+                            162 ; ---------------------------------
+   0083                     163 _pio_set_interrupts_mask::
+                            164 ;pio.c:38: _pio_control(port, (control | 0x17));
+   0083 21 04 00      [10]  165 	ld	hl, #4+0
+   0086 39            [11]  166 	add	hl, sp
+   0087 7E            [ 7]  167 	ld	a, (hl)
+   0088 F6 17         [ 7]  168 	or	a, #0x17
+   008A 4F            [ 4]  169 	ld	c,a
+   008B D1            [10]  170 	pop	de
+   008C E1            [10]  171 	pop	hl
+   008D E5            [11]  172 	push	hl
+   008E D5            [11]  173 	push	de
+                            174 ;pio.c:13: *(pio_ctrl + port) = cmd;
+   008F FD 2Ar02r00   [20]  175 	ld	iy,(_pio_ctrl)
+   0093 5D            [ 4]  176 	ld	e, l
+   0094 54            [ 4]  177 	ld	d, h
+   0095 FD 19         [15]  178 	add	iy, de
+   0097 FD 71 00      [19]  179 	ld	0 (iy), c
+                            180 ;pio.c:39: _pio_control(port, mask);
+   009A FD 21 06 00   [14]  181 	ld	iy,#6
+   009E FD 39         [15]  182 	add	iy,sp
+   00A0 FD 4E 00      [19]  183 	ld	c,0 (iy)
+                            184 ;pio.c:13: *(pio_ctrl + port) = cmd;
+   00A3 ED 5Br02r00   [20]  185 	ld	de,(_pio_ctrl)
+   00A7 19            [11]  186 	add	hl,de
+   00A8 71            [ 7]  187 	ld	(hl),c
+                            188 ;pio.c:39: _pio_control(port, mask);
+   00A9 C9            [10]  189 	ret
+                            190 ;pio.c:42: uint8_t pio_read(int port)
+                            191 ;	---------------------------------
+                            192 ; Function pio_read
+                            193 ; ---------------------------------
+   00AA                     194 _pio_read::
+                            195 ;pio.c:44: return *(pio_port + port);
+   00AA 21 02 00      [10]  196 	ld	hl,#2
+   00AD 39            [11]  197 	add	hl,sp
+   00AE FD 21r00r00   [14]  198 	ld	iy,#_pio_port
+   00B2 FD 7E 00      [19]  199 	ld	a,0 (iy)
+   00B5 86            [ 7]  200 	add	a, (hl)
+   00B6 4F            [ 4]  201 	ld	c,a
+   00B7 FD 7E 01      [19]  202 	ld	a,1 (iy)
+   00BA 23            [ 6]  203 	inc	hl
+   00BB 8E            [ 7]  204 	adc	a, (hl)
+   00BC 47            [ 4]  205 	ld	b,a
+   00BD 0A            [ 7]  206 	ld	a,(bc)
+   00BE 6F            [ 4]  207 	ld	l,a
+   00BF C9            [10]  208 	ret
+                            209 ;pio.c:47: void pio_write(int port, uint8_t data)
+                            210 ;	---------------------------------
+                            211 ; Function pio_write
+                            212 ; ---------------------------------
+   00C0                     213 _pio_write::
+                            214 ;pio.c:49: _pio_data(port, data);
+   00C0 21 04 00      [10]  215 	ld	hl, #4+0
+   00C3 39            [11]  216 	add	hl, sp
+   00C4 4E            [ 7]  217 	ld	c, (hl)
+   00C5 D1            [10]  218 	pop	de
+   00C6 E1            [10]  219 	pop	hl
+   00C7 E5            [11]  220 	push	hl
+   00C8 D5            [11]  221 	push	de
+                            222 ;pio.c:8: *(pio_port + port) = data;
+   00C9 ED 5Br00r00   [20]  223 	ld	de,(_pio_port)
+   00CD 19            [11]  224 	add	hl,de
+   00CE 71            [ 7]  225 	ld	(hl),c
+                            226 ;pio.c:49: _pio_data(port, data);
+   00CF C9            [10]  227 	ret
+                            228 	.area _CODE
+                            229 	.area _INITIALIZER
+   0000                     230 __xinit__pio_port:
+   0000 00 42               231 	.dw #0x4200
+   0002                     232 __xinit__pio_ctrl:
+   0002 02 42               233 	.dw #0x4202
+                            234 	.area _CABS (ABS)
diff --git a/sw/z80_tests/usart/build/pio.rel b/sw/z80/drivers/build/pio.rel
index 90210a9..d9b1ac3 100644
--- a/sw/z80_tests/usart/build/pio.rel
+++ b/sw/z80/drivers/build/pio.rel
@@ -1,13 +1,15 @@
 XL2
-H 9 areas 6 global symbols
+H 9 areas 8 global symbols
 M pio
 O -mz80
 S .__.ABS. Def0000
-A _CODE size AA flags 0 addr 0
+A _CODE size D0 flags 0 addr 0
 S _pio_set_interrupts Def0070
 S _pio_set_mode Def0034
 S _pio_set_interrupts_mask Def0083
+S _pio_read Def00AA
 S __pio_control Def001A
+S _pio_write Def00C0
 S __pio_data Def0000
 A _DATA size 0 flags 0 addr 0
 A _INITIALIZED size 4 flags 0 addr 0
@@ -63,6 +65,18 @@ T 91 00 02 00 5D 54 FD 19 FD 71 00 FD 21 06 00 FD
 R 00 00 00 00 00 02 02 00
 T 9F 00 39 FD 4E 00 ED 5B 02 00 19 71 C9
 R 00 00 00 00 00 08 02 00
+T AA 00
+R 00 00 00 00
+T AA 00 21 02 00 39 FD 21 00 00 FD 7E 00 86 4F FD
+R 00 00 00 00 00 08 02 00
+T B8 00 7E 01 23 8E 47 0A 6F C9
+R 00 00 00 00
+T C0 00
+R 00 00 00 00
+T C0 00 21 04 00 39 4E D1 E1 E5 D5 ED 5B 00 00 19
+R 00 00 00 00 00 0D 02 00
+T CE 00 71 C9
+R 00 00 00 00
 T 00 00
 R 00 00 07 00
 T 00 00 00 42
diff --git a/sw/z80_tests/usart/build/pio.sym b/sw/z80/drivers/build/pio.sym
index 3cf582f..52f787c 100644
--- a/sw/z80_tests/usart/build/pio.sym
+++ b/sw/z80/drivers/build/pio.sym
@@ -13,17 +13,18 @@ Symbol Table
   7 __xinit__pio_port                                              0000 R
   2 _pio_ctrl                                                      0002 R
   2 _pio_port                                                      0000 R
+  0 _pio_read                                                      00AA GR
   0 _pio_set_interrupts                                            0070 GR
   0 _pio_set_interrupts_mask                                       0083 GR
   0 _pio_set_mode                                                  0034 GR
-
+  0 _pio_write                                                     00C0 GR
 
 ASxxxx Assembler V02.00 + NoICE + SDCC mods  (Zilog Z80 / Hitachi HD64180), page 2.
 Hexadecimal [16-Bits]
 
 Area Table
 
-   0 _CODE                                      size   AA   flags    0
+   0 _CODE                                      size   D0   flags    0
    1 _DATA                                      size    0   flags    0
    2 _INITIALIZED                               size    4   flags    0
    3 _DABS                                      size    0   flags    8
diff --git a/sw/z80_tests/usart/build/usart.asm b/sw/z80/drivers/build/usart.asm
index 58d6fdf..fb65d62 100644
--- a/sw/z80_tests/usart/build/usart.asm
+++ b/sw/z80/drivers/build/usart.asm
@@ -366,14 +366,14 @@ _usart_read::
 	ld	sp,hl
 ;usart.c:77: uint8_t *bp = buffer;
 	ld	a,4 (ix)
-	ld	-6 (ix),a
+	ld	-4 (ix),a
 	ld	a,5 (ix)
-	ld	-5 (ix),a
+	ld	-3 (ix),a
 ;usart.c:80: while (count--) {
 	ld	c,6 (ix)
 	ld	b,7 (ix)
-	ld	-4 (ix),#0x00
-	ld	-3 (ix),#0x00
+	ld	hl,#0x0000
+	ex	(sp), hl
 00105$:
 	ld	e, c
 	ld	d, b
@@ -384,12 +384,12 @@ _usart_read::
 ;usart.c:81: *(bp++) = _usart->buffer;
 	ld	hl,(__usart)
 	ld	e,(hl)
-	pop	hl
-	push	hl
+	ld	l,-4 (ix)
+	ld	h,-3 (ix)
 	ld	(hl),e
-	inc	-6 (ix)
+	inc	-4 (ix)
 	jr	NZ,00123$
-	inc	-5 (ix)
+	inc	-3 (ix)
 00123$:
 	ld	de,(__usart)
 ;usart.c:83: if (_usart->LSR.framing_error || _usart->LSR.parity_error) {
@@ -414,23 +414,22 @@ _usart_read::
 	jr	Z,00102$
 00101$:
 ;usart.c:84: bp--; // delete last byte (?)
-	pop	hl
-	push	hl
+	ld	l,-4 (ix)
+	ld	h,-3 (ix)
 	dec	hl
-	ex	(sp), hl
+	ld	-4 (ix),l
+	ld	-3 (ix),h
 	jr	00105$
 00102$:
 ;usart.c:86: read_count++;
-	inc	-4 (ix)
+	inc	-6 (ix)
 	jr	NZ,00105$
-	inc	-3 (ix)
+	inc	-5 (ix)
 	jr	00105$
 00107$:
 ;usart.c:90: return read_count;
-	pop	bc
 	pop	hl
 	push	hl
-	push	bc
 	ld	sp, ix
 	pop	ix
 	ret
diff --git a/sw/z80_tests/usart/build/usart.lst b/sw/z80/drivers/build/usart.lst
index 7706cff..65365fe 100644
--- a/sw/z80_tests/usart/build/usart.lst
+++ b/sw/z80/drivers/build/usart.lst
@@ -366,30 +366,30 @@
    01A4 F9            [ 6]  366 	ld	sp,hl
                             367 ;usart.c:77: uint8_t *bp = buffer;
    01A5 DD 7E 04      [19]  368 	ld	a,4 (ix)
-   01A8 DD 77 FA      [19]  369 	ld	-6 (ix),a
+   01A8 DD 77 FC      [19]  369 	ld	-4 (ix),a
    01AB DD 7E 05      [19]  370 	ld	a,5 (ix)
-   01AE DD 77 FB      [19]  371 	ld	-5 (ix),a
+   01AE DD 77 FD      [19]  371 	ld	-3 (ix),a
                             372 ;usart.c:80: while (count--) {
    01B1 DD 4E 06      [19]  373 	ld	c,6 (ix)
    01B4 DD 46 07      [19]  374 	ld	b,7 (ix)
-   01B7 DD 36 FC 00   [19]  375 	ld	-4 (ix),#0x00
-   01BB DD 36 FD 00   [19]  376 	ld	-3 (ix),#0x00
-   01BF                     377 00105$:
-   01BF 59            [ 4]  378 	ld	e, c
-   01C0 50            [ 4]  379 	ld	d, b
-   01C1 0B            [ 6]  380 	dec	bc
-   01C2 7A            [ 4]  381 	ld	a,d
-   01C3 B3            [ 4]  382 	or	a,e
-   01C4 28 48         [12]  383 	jr	Z,00107$
+   01B7 21 00 00      [10]  375 	ld	hl,#0x0000
+   01BA E3            [19]  376 	ex	(sp), hl
+   01BB                     377 00105$:
+   01BB 59            [ 4]  378 	ld	e, c
+   01BC 50            [ 4]  379 	ld	d, b
+   01BD 0B            [ 6]  380 	dec	bc
+   01BE 7A            [ 4]  381 	ld	a,d
+   01BF B3            [ 4]  382 	or	a,e
+   01C0 28 55         [12]  383 	jr	Z,00107$
                             384 ;usart.c:81: *(bp++) = _usart->buffer;
-   01C6 2Ar00r00      [16]  385 	ld	hl,(__usart)
-   01C9 5E            [ 7]  386 	ld	e,(hl)
-   01CA E1            [10]  387 	pop	hl
-   01CB E5            [11]  388 	push	hl
+   01C2 2Ar00r00      [16]  385 	ld	hl,(__usart)
+   01C5 5E            [ 7]  386 	ld	e,(hl)
+   01C6 DD 6E FC      [19]  387 	ld	l,-4 (ix)
+   01C9 DD 66 FD      [19]  388 	ld	h,-3 (ix)
    01CC 73            [ 7]  389 	ld	(hl),e
-   01CD DD 34 FA      [23]  390 	inc	-6 (ix)
+   01CD DD 34 FC      [23]  390 	inc	-4 (ix)
    01D0 20 03         [12]  391 	jr	NZ,00123$
-   01D2 DD 34 FB      [23]  392 	inc	-5 (ix)
+   01D2 DD 34 FD      [23]  392 	inc	-3 (ix)
    01D5                     393 00123$:
    01D5 ED 5Br00r00   [20]  394 	ld	de,(__usart)
                             395 ;usart.c:83: if (_usart->LSR.framing_error || _usart->LSR.parity_error) {
@@ -411,31 +411,30 @@
    01F8 0F            [ 4]  411 	rrca
    01F9 0F            [ 4]  412 	rrca
    01FA E6 01         [ 7]  413 	and	a,#0x01
-   01FC 28 06         [12]  414 	jr	Z,00102$
+   01FC 28 0F         [12]  414 	jr	Z,00102$
    01FE                     415 00101$:
                             416 ;usart.c:84: bp--; // delete last byte (?)
-   01FE E1            [10]  417 	pop	hl
-   01FF E5            [11]  418 	push	hl
-   0200 2B            [ 6]  419 	dec	hl
-   0201 E3            [19]  420 	ex	(sp), hl
-   0202 18 BB         [12]  421 	jr	00105$
-   0204                     422 00102$:
-                            423 ;usart.c:86: read_count++;
-   0204 DD 34 FC      [23]  424 	inc	-4 (ix)
-   0207 20 B6         [12]  425 	jr	NZ,00105$
-   0209 DD 34 FD      [23]  426 	inc	-3 (ix)
-   020C 18 B1         [12]  427 	jr	00105$
-   020E                     428 00107$:
-                            429 ;usart.c:90: return read_count;
-   020E C1            [10]  430 	pop	bc
-   020F E1            [10]  431 	pop	hl
-   0210 E5            [11]  432 	push	hl
-   0211 C5            [11]  433 	push	bc
-   0212 DD F9         [10]  434 	ld	sp, ix
-   0214 DD E1         [14]  435 	pop	ix
-   0216 C9            [10]  436 	ret
-                            437 	.area _CODE
-                            438 	.area _INITIALIZER
-   0000                     439 __xinit___usart:
-   0000 00 40               440 	.dw #0x4000
-                            441 	.area _CABS (ABS)
+   01FE DD 6E FC      [19]  417 	ld	l,-4 (ix)
+   0201 DD 66 FD      [19]  418 	ld	h,-3 (ix)
+   0204 2B            [ 6]  419 	dec	hl
+   0205 DD 75 FC      [19]  420 	ld	-4 (ix),l
+   0208 DD 74 FD      [19]  421 	ld	-3 (ix),h
+   020B 18 AE         [12]  422 	jr	00105$
+   020D                     423 00102$:
+                            424 ;usart.c:86: read_count++;
+   020D DD 34 FA      [23]  425 	inc	-6 (ix)
+   0210 20 A9         [12]  426 	jr	NZ,00105$
+   0212 DD 34 FB      [23]  427 	inc	-5 (ix)
+   0215 18 A4         [12]  428 	jr	00105$
+   0217                     429 00107$:
+                            430 ;usart.c:90: return read_count;
+   0217 E1            [10]  431 	pop	hl
+   0218 E5            [11]  432 	push	hl
+   0219 DD F9         [10]  433 	ld	sp, ix
+   021B DD E1         [14]  434 	pop	ix
+   021D C9            [10]  435 	ret
+                            436 	.area _CODE
+                            437 	.area _INITIALIZER
+   0000                     438 __xinit___usart:
+   0000 00 40               439 	.dw #0x4000
+                            440 	.area _CABS (ABS)
diff --git a/sw/z80_tests/usart/build/usart.rel b/sw/z80/drivers/build/usart.rel
index 480c037..29ad600 100644
--- a/sw/z80_tests/usart/build/usart.rel
+++ b/sw/z80/drivers/build/usart.rel
@@ -3,7 +3,7 @@ H 9 areas B global symbols
 M usart
 O -mz80
 S .__.ABS. Def0000
-A _CODE size 217 flags 0 addr 0
+A _CODE size 21E flags 0 addr 0
 S _usart_read Def0198
 S _usart_set_autoflow Def00CE
 S _usart_word_length Def00B5
@@ -146,15 +146,15 @@ T 98 01
 R 00 00 00 00
 T 98 01 DD E5 DD 21 00 00 DD 39 21 FA FF 39 F9 DD
 R 00 00 00 00
-T A6 01 7E 04 DD 77 FA DD 7E 05 DD 77 FB DD 4E 06
+T A6 01 7E 04 DD 77 FC DD 7E 05 DD 77 FD DD 4E 06
 R 00 00 00 00
-T B4 01 DD 46 07 DD 36 FC 00 DD 36 FD 00
+T B4 01 DD 46 07 21 00 00 E3
 R 00 00 00 00
-T BF 01
+T BB 01
 R 00 00 00 00
-T BF 01 59 50 0B 7A B3 28 48 2A 00 00 5E E1 E5 73
+T BB 01 59 50 0B 7A B3 28 55 2A 00 00 5E DD 6E FC
 R 00 00 00 00 00 0A 02 00
-T CD 01 DD 34 FA 20 03 DD 34 FB
+T C9 01 DD 66 FD 73 DD 34 FC 20 03 DD 34 FD
 R 00 00 00 00
 T D5 01
 R 00 00 00 00
@@ -162,19 +162,21 @@ T D5 01 ED 5B 00 00 21 0D 00 19 DD 75 FE DD 74 FF
 R 00 00 00 00 00 04 02 00
 T E3 01 DD 6E FE DD 66 FF 7E 0F 0F 0F E6 01 20 0D
 R 00 00 00 00
-T F1 01 DD 6E FE DD 66 FF 7E 0F 0F E6 01 28 06
+T F1 01 DD 6E FE DD 66 FF 7E 0F 0F E6 01 28 0F
 R 00 00 00 00
 T FE 01
 R 00 00 00 00
-T FE 01 E1 E5 2B E3 18 BB
+T FE 01 DD 6E FC DD 66 FD 2B DD 75 FC DD 74 FD 18
 R 00 00 00 00
-T 04 02
+T 0C 02 AE
 R 00 00 00 00
-T 04 02 DD 34 FC 20 B6 DD 34 FD 18 B1
+T 0D 02
 R 00 00 00 00
-T 0E 02
+T 0D 02 DD 34 FA 20 A9 DD 34 FB 18 A4
 R 00 00 00 00
-T 0E 02 C1 E1 E5 C5 DD F9 DD E1 C9
+T 17 02
+R 00 00 00 00
+T 17 02 E1 E5 DD F9 DD E1 C9
 R 00 00 00 00
 T 00 00
 R 00 00 07 00
diff --git a/sw/z80_tests/usart/build/usart.sym b/sw/z80/drivers/build/usart.sym
index a6e3c38..71004e3 100644
--- a/sw/z80_tests/usart/build/usart.sym
+++ b/sw/z80/drivers/build/usart.sym
@@ -26,7 +26,7 @@ Hexadecimal [16-Bits]
 
 Area Table
 
-   0 _CODE                                      size  217   flags    0
+   0 _CODE                                      size  21E   flags    0
    1 _DATA                                      size    0   flags    0
    2 _INITIALIZED                               size    2   flags    0
    3 _DABS                                      size    0   flags    8
diff --git a/sw/z80/kernel/drivers/ctc.c b/sw/z80/drivers/ctc.c
index 841202a..5ac4254 100644
--- a/sw/z80/kernel/drivers/ctc.c
+++ b/sw/z80/drivers/ctc.c
@@ -1,4 +1,4 @@
-#include "drivers/ctc.h"
+#include "ctc.h"
 
 void ctc_control()
 {
diff --git a/sw/z80/kernel/include/drivers/ctc.h b/sw/z80/drivers/include/ctc.h
index 80e8b4b..80e8b4b 100644
--- a/sw/z80/kernel/include/drivers/ctc.h
+++ b/sw/z80/drivers/include/ctc.h
diff --git a/sw/z80/kernel/include/drivers/pio.h b/sw/z80/drivers/include/pio.h
index 0df2ed0..e91029c 100644
--- a/sw/z80/kernel/include/drivers/pio.h
+++ b/sw/z80/drivers/include/pio.h
@@ -1,8 +1,8 @@
 #ifndef __PIO_H__
 #define __PIO_H__
 
-#include "devices.h"
-#include "types.h"
+#include "addresses.h"
+#include <stdint.h>
 
 #define PIO_A       0
 #define PIO_B       1
@@ -20,6 +20,7 @@
 inline void _pio_data(int port, uint8_t data);
 inline void _pio_control(int port, uint8_t cmd);
 
+/* the last argument is needed only for IO mode */
 void pio_set_mode(int port, int mode, uint8_t io);
 
 void pio_set_interrupts(int port, int control);
@@ -34,4 +35,4 @@ inline void pio_write_pin(int port, uint8_t pin);
 
 // TODO: implement mode (in/out/both) and interrupt vector
 
-#endif // __PIO_H__
+#endif /* __PIO_H__ */
diff --git a/sw/z80/kernel/include/drivers/usart.h b/sw/z80/drivers/include/usart.h
index b85ee3e..bb06aab 100644
--- a/sw/z80/kernel/include/drivers/usart.h
+++ b/sw/z80/drivers/include/usart.h
@@ -1,10 +1,10 @@
 #ifndef __USART_H__
 #define __USART_H__
 
-#include "types.h"
-#include "devices.h"
+#include "addresses.h"
 
-#include "string.h"
+#include <stdint.h>
+#include <string.h>
 
 // baudrate clock divisors 
 // values from TL16C550C datasheet (table 9 for 1.8432 MHz crystal)
@@ -48,6 +48,9 @@
 #define USART_AUTOFLOW_CTS      2
 #define USART_AUTOFLOW_OFF      0
 
+typedef unsigned int    uint;
+typedef uint8_t         register_t;
+
 /* stuctures for usart registers */
 struct IER 
 {
diff --git a/sw/z80/drivers/makefile b/sw/z80/drivers/makefile
new file mode 100644
index 0000000..5d6d8ee
--- /dev/null
+++ b/sw/z80/drivers/makefile
@@ -0,0 +1,22 @@
+# Drivers library
+
+LIB     := build/drivers.a
+SOURCES := $(wildcard *.c)
+OBJECTS := $(patsubst %.c,build/%.rel,$(SOURCES))
+
+CC := sdcc
+AR := sdar
+CFLAGS := -mz80 -Iinclude -I../arch -DDEBUG
+
+.PHONY: dirs clean
+$(LIB): $(OBJECTS)
+	$(AR) rcs $@ $(OBJECTS)
+
+$(OBJECTS): build/%.rel: %.c $(SOURCES) dirs
+	$(CC) $(CFLAGS) -c $< -o $@
+
+dirs:
+	mkdir -p build
+
+clean:
+	- rm -rd build/*
diff --git a/sw/z80/kernel/drivers/pio.c b/sw/z80/drivers/pio.c
index 4321fb8..bdbe1c3 100644
--- a/sw/z80/kernel/drivers/pio.c
+++ b/sw/z80/drivers/pio.c
@@ -1,4 +1,4 @@
-#include "drivers/pio.h"
+#include "pio.h"
 
 static uint8_t *pio_port = (uint8_t *) ADDR_DEV_PIO;
 static uint8_t *pio_ctrl = (uint8_t *) (ADDR_DEV_PIO + 2);
@@ -34,7 +34,17 @@ void pio_set_interrupts(int port, int control)
 void pio_set_interrupts_mask(int port, int control, uint8_t mask)
 {
     // 0x17 is a control sequence to set interrupts
-    // and to interpret the next byte as a mask
+    // AND interpret the next byte as a bitmask
     _pio_control(port, (control | 0x17));
     _pio_control(port, mask);
 }
+
+uint8_t pio_read(int port)
+{
+    return *(pio_port + port);
+}
+
+void pio_write(int port, uint8_t data)
+{
+    _pio_data(port, data);
+}
diff --git a/sw/z80/kernel/drivers/usart.c b/sw/z80/drivers/usart.c
index c54fe37..9ec6dbd 100644
--- a/sw/z80/kernel/drivers/usart.c
+++ b/sw/z80/drivers/usart.c
@@ -1,4 +1,4 @@
-#include "drivers/usart.h"
+#include "usart.h"
 
 static struct _usart_device *_usart = (struct _usart_device *) ADDR_DEV_USART;
 
diff --git a/sw/z80/crt0.s b/sw/z80/kernel/crt0.s
index 00c7da1..00c7da1 100644
--- a/sw/z80/crt0.s
+++ b/sw/z80/kernel/crt0.s
diff --git a/sw/z80/makefile b/sw/z80/kernel/makefile
index 5ab7e93..be8eed4 100644
--- a/sw/z80/makefile
+++ b/sw/z80/kernel/makefile
@@ -3,9 +3,8 @@
 #
 OSNAME := helvetiOS
  
-CSOURCES 	:=  $(wildcard kernel/*.c) \
-				$(wildcard kernel/drivers/*.c) \
-				$(wildcard libc/*.c) 
+CSOURCES 	:=  $(wildcard *.c) \
+				$(wildcard drivers/*.c)
 
 OBJECTS 	:= $(patsubst %.c,build/%.rel,$(CSOURCES))
 HEXFILE		:= build/$(OSNAME).hex
@@ -17,13 +16,13 @@ BINARY  	:= build/$(OSNAME).bin
 CC 		:= sdcc
 
 CFLAGS	:= -mz80 \
-			-I kernel/include \
-			-I kernel/include/drivers \
+			-I include \
+			-I include/drivers \
 			-I libc/include \
 			--opt-code-size \
 			-DDEBUG
 
-LDFLAGS := -mz80 --no-std-crt0 crt0.rel \
+LDFLAGS := -mz80 --no-std-crt0 build/crt0.rel \
 			--std-c89 -pedantic \
 			--code-loc 0x0800 --data-loc 0x8000
 
@@ -33,21 +32,20 @@ all: $(BINARY)
 # build binary
 $(BINARY): $(OBJECTS) dirs
 	$(CC) $(LDFLAGS) $(OBJECTS) -o $(HEXFILE)
-	@# xxd -r -p $(HEXFILE) $(BINARY)
 	makebin -s 16384 $(HEXFILE) $(BINARY)
 
-$(OBJECTS): build/%.rel : %.c $(CSOURCES) dirs crt0.rel
+$(OBJECTS): build/%.rel : %.c $(CSOURCES) dirs build/crt0.rel
 	@printf "\n"
 	$(CC) $(CFLAGS) -c $< -o $@
 
-crt0.rel: crt0.s
+build/crt0.rel: crt0.s
 	sdasz80 -o $<
+	@mv crt0.rel build
 
 dirs:
 	mkdir -p build build/kernel build/libc build/kernel/drivers
 
 dis: $(BINARY)
-	@# z80dasm -a -l -g 0h $< -o build/$(OSNAME).s
 	dz80 -b -n $<
 
 clean:
diff --git a/sw/z80_tests/usart/types.h b/sw/z80/libc/include/stdint.h
index 815fc68..5e8caf3 100644
--- a/sw/z80_tests/usart/types.h
+++ b/sw/z80/libc/include/stdint.h
@@ -1,13 +1,13 @@
-#ifndef __TYPES_H__
-#define __TYPES_H__
-
-/* only types from primitive types are defined in this file */ 
-
-typedef volatile unsigned char      register_t;
+#ifndef __STDINT_H__
+#define __STDINT_H__
 
 typedef unsigned int                uint;
+
 typedef char                        int8_t;
 typedef unsigned char               uint8_t;
 typedef int                         int16_t;
 typedef unsigned int                uint16_t;
-#endif
+typedef long int                    int32_t;
+typedef unsigned long int           uint32_t;
+
+#endif // __STDINT_H__
\ No newline at end of file
diff --git a/sw/z80/libc/include/stdlib.h b/sw/z80/libc/include/stdlib.h
new file mode 100644
index 0000000..c69f573
--- /dev/null
+++ b/sw/z80/libc/include/stdlib.h
@@ -0,0 +1,7 @@
+#ifndef __STDLIB_H__
+#define __STDLIB_H__
+
+#include "stdint.h"
+
+
+#endif // __STDLIB_H__
\ No newline at end of file
diff --git a/sw/z80/libc/include/types.h b/sw/z80/libc/include/types.h
new file mode 100644
index 0000000..a083bfe
--- /dev/null
+++ b/sw/z80/libc/include/types.h
@@ -0,0 +1,60 @@
+#ifndef __TYPES_H__
+#define __TYPES_H__
+
+/* only types from primitive types are defined in this file */ 
+
+typedef volatile unsigned char      register_t;
+
+typedef unsigned int                uint;
+
+typedef char                        int8_t;
+typedef unsigned char               uint8_t;
+typedef int                         int16_t;
+typedef unsigned int                uint16_t;
+typedef long int                    int32_t;
+typedef unsigned long int           uint32_t;
+
+typedef uint16_t                    size_t;
+typedef int16_t                     ssize_t;
+
+typedef uint8_t                     pid_t;
+typedef uint16_t                    ino_t;
+
+typedef uint8_t                     dev_t;
+typedef uint32_t                    devsize_t;
+typedef uint8_t                     fd_t;
+typedef uint16_t                    blk_t;
+typedef uint8_t                     user_t; 
+typedef struct {
+    uint8_t member[3];
+} uint24_t;
+
+typedef uint32_t                    fsize_t;
+
+typedef struct 
+{
+    dev_t   dev;    // device id, global in the fs
+    ino_t   inode;    // inode id relative to the volume
+
+} inode_t;
+
+typedef struct time_s
+{
+    struct
+    {
+        uint    minutes :6;
+        uint    hour    :5;
+
+    } time;
+
+    struct
+    {
+        uint    day     :5;
+        uint    month   :4;
+        uint    year    :12;
+
+    } date;
+
+} time_t;
+
+#endif
diff --git a/sw/z80_tests/usart/build/crt0.rel b/sw/z80/tests/pio/build/crt0.rel
index 809c0e6..809c0e6 100644
--- a/sw/z80_tests/usart/build/crt0.rel
+++ b/sw/z80/tests/pio/build/crt0.rel
diff --git a/sw/z80_tests/usart/build/main.asm b/sw/z80/tests/pio/build/main.asm
index 44f199a..453eead 100644
--- a/sw/z80_tests/usart/build/main.asm
+++ b/sw/z80/tests/pio/build/main.asm
@@ -9,8 +9,8 @@
 ; Public variables in this module
 ;--------------------------------------------------------
 	.globl _main
-	.globl _usart_write
-	.globl _usart_init
+	.globl _pio_write
+	.globl _pio_set_mode
 ;--------------------------------------------------------
 ; special function registers
 ;--------------------------------------------------------
@@ -47,44 +47,34 @@
 ; Function main
 ; ---------------------------------
 _main::
-;main.c:5: usart_init(USART_BAUDRATE_1200, USART_PARITY_EVEN, USART_STOP_BITS_1);
-	ld	hl,#0x000a
+;main.c:7: pio_set_mode(PIO_A, PIO_MODE_BYTE_OUT, 0);
+	xor	a, a
+	push	af
+	inc	sp
+	ld	hl,#0x0001
 	push	hl
-	ld	l, #0x01
+	ld	l, #0x00
 	push	hl
-	ld	l, #0x60
-	push	hl
-	call	_usart_init
-	ld	hl,#6
-	add	hl,sp
-	ld	sp,hl
-;main.c:6: usart_write("Hello, World!\n", 13);
-	ld	hl,#0x000d
-	push	hl
-	ld	hl,#___str_0
-	push	hl
-	call	_usart_write
+	call	_pio_set_mode
 	pop	af
 	pop	af
-;main.c:8: while(1) {
+	inc	sp
+;main.c:9: while (1) {
+	ld	c,#0x00
 00102$:
-;main.c:9: usart_write("done\n", 5);
-	ld	hl,#0x0005
+;main.c:10: pio_write(PIO_A, j++);
+	ld	b,c
+	inc	c
+	push	bc
+	push	bc
+	inc	sp
+	ld	hl,#0x0000
 	push	hl
-	ld	hl,#___str_1
-	push	hl
-	call	_usart_write
-	pop	af
+	call	_pio_write
 	pop	af
+	inc	sp
+	pop	bc
 	jr	00102$
-___str_0:
-	.ascii "Hello, World!"
-	.db 0x0a
-	.db 0x00
-___str_1:
-	.ascii "done"
-	.db 0x0a
-	.db 0x00
 	.area _CODE
 	.area _INITIALIZER
 	.area _CABS (ABS)
diff --git a/sw/z80_tests/usart/build/main.lst b/sw/z80/tests/pio/build/main.lst
index c7b4201..4a1a872 100644
--- a/sw/z80_tests/usart/build/main.lst
+++ b/sw/z80/tests/pio/build/main.lst
@@ -9,8 +9,8 @@
                               9 ; Public variables in this module
                              10 ;--------------------------------------------------------
                              11 	.globl _main
-                             12 	.globl _usart_write
-                             13 	.globl _usart_init
+                             12 	.globl _pio_write
+                             13 	.globl _pio_set_mode
                              14 ;--------------------------------------------------------
                              15 ; special function registers
                              16 ;--------------------------------------------------------
@@ -47,46 +47,34 @@
                              47 ; Function main
                              48 ; ---------------------------------
    0000                      49 _main::
-                             50 ;main.c:5: usart_init(USART_BAUDRATE_1200, USART_PARITY_EVEN, USART_STOP_BITS_1);
-   0000 21 0A 00      [10]   51 	ld	hl,#0x000a
-   0003 E5            [11]   52 	push	hl
-   0004 2E 01         [ 7]   53 	ld	l, #0x01
-   0006 E5            [11]   54 	push	hl
-   0007 2E 60         [ 7]   55 	ld	l, #0x60
-   0009 E5            [11]   56 	push	hl
-   000A CDr00r00      [17]   57 	call	_usart_init
-   000D 21 06 00      [10]   58 	ld	hl,#6
-   0010 39            [11]   59 	add	hl,sp
-   0011 F9            [ 6]   60 	ld	sp,hl
-                             61 ;main.c:6: usart_write("Hello, World!\n", 13);
-   0012 21 0D 00      [10]   62 	ld	hl,#0x000d
-   0015 E5            [11]   63 	push	hl
-   0016 21r2Er00      [10]   64 	ld	hl,#___str_0
-   0019 E5            [11]   65 	push	hl
-   001A CDr00r00      [17]   66 	call	_usart_write
-   001D F1            [10]   67 	pop	af
-   001E F1            [10]   68 	pop	af
-                             69 ;main.c:8: while(1) {
-   001F                      70 00102$:
-                             71 ;main.c:9: usart_write("done\n", 5);
-   001F 21 05 00      [10]   72 	ld	hl,#0x0005
-   0022 E5            [11]   73 	push	hl
-   0023 21r3Dr00      [10]   74 	ld	hl,#___str_1
-   0026 E5            [11]   75 	push	hl
-   0027 CDr00r00      [17]   76 	call	_usart_write
-   002A F1            [10]   77 	pop	af
-   002B F1            [10]   78 	pop	af
-   002C 18 F1         [12]   79 	jr	00102$
-   002E                      80 ___str_0:
-   002E 48 65 6C 6C 6F 2C    81 	.ascii "Hello, World!"
-        20 57 6F 72 6C 64
-        21
-   003B 0A                   82 	.db 0x0a
-   003C 00                   83 	.db 0x00
-   003D                      84 ___str_1:
-   003D 64 6F 6E 65          85 	.ascii "done"
-   0041 0A                   86 	.db 0x0a
-   0042 00                   87 	.db 0x00
-                             88 	.area _CODE
-                             89 	.area _INITIALIZER
-                             90 	.area _CABS (ABS)
+                             50 ;main.c:7: pio_set_mode(PIO_A, PIO_MODE_BYTE_OUT, 0);
+   0000 AF            [ 4]   51 	xor	a, a
+   0001 F5            [11]   52 	push	af
+   0002 33            [ 6]   53 	inc	sp
+   0003 21 01 00      [10]   54 	ld	hl,#0x0001
+   0006 E5            [11]   55 	push	hl
+   0007 2E 00         [ 7]   56 	ld	l, #0x00
+   0009 E5            [11]   57 	push	hl
+   000A CDr00r00      [17]   58 	call	_pio_set_mode
+   000D F1            [10]   59 	pop	af
+   000E F1            [10]   60 	pop	af
+   000F 33            [ 6]   61 	inc	sp
+                             62 ;main.c:9: while (1) {
+   0010 0E 00         [ 7]   63 	ld	c,#0x00
+   0012                      64 00102$:
+                             65 ;main.c:10: pio_write(PIO_A, j++);
+   0012 41            [ 4]   66 	ld	b,c
+   0013 0C            [ 4]   67 	inc	c
+   0014 C5            [11]   68 	push	bc
+   0015 C5            [11]   69 	push	bc
+   0016 33            [ 6]   70 	inc	sp
+   0017 21 00 00      [10]   71 	ld	hl,#0x0000
+   001A E5            [11]   72 	push	hl
+   001B CDr00r00      [17]   73 	call	_pio_write
+   001E F1            [10]   74 	pop	af
+   001F 33            [ 6]   75 	inc	sp
+   0020 C1            [10]   76 	pop	bc
+   0021 18 EF         [12]   77 	jr	00102$
+                             78 	.area _CODE
+                             79 	.area _INITIALIZER
+                             80 	.area _CABS (ABS)
diff --git a/sw/z80/tests/pio/build/main.rel b/sw/z80/tests/pio/build/main.rel
new file mode 100644
index 0000000..bc2bd98
--- /dev/null
+++ b/sw/z80/tests/pio/build/main.rel
@@ -0,0 +1,29 @@
+XL2
+H 9 areas 4 global symbols
+M main
+O -mz80
+S _pio_set_mode Ref0000
+S .__.ABS. Def0000
+S _pio_write Ref0000
+A _CODE size 23 flags 0 addr 0
+S _main Def0000
+A _DATA size 0 flags 0 addr 0
+A _INITIALIZED size 0 flags 0 addr 0
+A _DABS size 0 flags 8 addr 0
+A _HOME size 0 flags 0 addr 0
+A _GSINIT size 0 flags 0 addr 0
+A _GSFINAL size 0 flags 0 addr 0
+A _INITIALIZER size 0 flags 0 addr 0
+A _CABS size 0 flags 8 addr 0
+T 00 00
+R 00 00 00 00
+T 00 00 AF F5 33 21 01 00 E5 2E 00 E5 CD 00 00 F1
+R 00 00 00 00 02 0D 00 00
+T 0E 00 F1 33 0E 00
+R 00 00 00 00
+T 12 00
+R 00 00 00 00
+T 12 00 41 0C C5 C5 33 21 00 00 E5 CD 00 00 F1 33
+R 00 00 00 00 02 0C 02 00
+T 20 00 C1 18 EF
+R 00 00 00 00
diff --git a/sw/z80_tests/usart/build/main.sym b/sw/z80/tests/pio/build/main.sym
index df02e0d..08d28a3 100644
--- a/sw/z80_tests/usart/build/main.sym
+++ b/sw/z80/tests/pio/build/main.sym
@@ -7,18 +7,17 @@ Symbol Table
     .__.ABS.                                                    =  0000 G
     .__.CPU.                                                    =  0000 L
     .__.H$L.                                                    =  0000 L
-  0 ___str_0                                                       002E R
-  0 ___str_1                                                       003D R
   0 _main                                                          0000 GR
-    _usart_init                                                    **** GX
-    _usart_write                                                   **** GX
+    _pio_set_mode                                                  **** GX
+    _pio_write                                                     **** GX
+
 
 ASxxxx Assembler V02.00 + NoICE + SDCC mods  (Zilog Z80 / Hitachi HD64180), page 2.
 Hexadecimal [16-Bits]
 
 Area Table
 
-   0 _CODE                                      size   43   flags    0
+   0 _CODE                                      size   23   flags    0
    1 _DATA                                      size    0   flags    0
    2 _INITIALIZED                               size    0   flags    0
    3 _DABS                                      size    0   flags    8
diff --git a/sw/z80_tests/usart/build/sample.lk b/sw/z80/tests/pio/build/pio_test.lk
index dc99ff1..20c32cc 100644
--- a/sw/z80_tests/usart/build/sample.lk
+++ b/sw/z80/tests/pio/build/pio_test.lk
@@ -1,12 +1,13 @@
 -mjwx
--i build/sample.hex
+-i build/pio_test.hex
 -b _CODE = 0x0800
 -b _DATA = 0x2000
+-k ../../drivers/build/
 -k /usr/libexec/../share/sdcc/lib/z80
 -k /usr/share/sdcc/lib/z80
+-l drivers.a
 -l z80
 build/crt0.rel
 build/main.rel
-build/usart.rel
 
 -e
diff --git a/sw/z80_tests/usart/build/sample.map b/sw/z80/tests/pio/build/pio_test.map
index e812f09..e91ef69 100644
--- a/sw/z80_tests/usart/build/sample.map
+++ b/sw/z80/tests/pio/build/pio_test.map
@@ -7,7 +7,7 @@ Area                                    Addr        Size        Decimal Bytes (A
 
       Value  Global                              Global Defined In Module
       -----  --------------------------------   ------------------------
-     00000000  .__.ABS.                           usart
+     00000000  .__.ABS.                           pio
      00000000  l__BSEG                         
      00000000  l__BSS                          
      00000000  l__CABS                         
@@ -36,44 +36,41 @@ Area                                    Addr        Size        Decimal Bytes (A
      00000002  l__HEADER5                      
      00000002  l__HEADER6                      
      00000002  l__HEADER7                      
-     00000002  l__INITIALIZED                  
-     00000002  l__INITIALIZER                  
      00000003  l__HEADER0                      
+     00000004  l__INITIALIZED                  
+     00000004  l__INITIALIZER                  
      00000006  l__GSINIT                       
      0000000C  l__HEADER8                      
-     00000264  l__CODE                         
+     000000FD  l__CODE                         
      00000800  s__CODE                         
-     00000A64  s__HOME                         
-     00000A64  s__INITIALIZER                  
-     00000A66  s__GSINIT                       
-     00000A6C  s__GSFINAL                      
+     000008FD  s__HOME                         
+     000008FD  s__INITIALIZER                  
+     00000901  s__GSINIT                       
+     00000907  s__GSFINAL                      
      00002000  s__DATA                         
      00002000  s__INITIALIZED                  
-     00002002  s__BSEG                         
-     00002002  s__BSS                          
-     00002002  s__HEAP                         
+     00002004  s__BSEG                         
+     00002004  s__BSS                          
+     00002004  s__HEAP                         
 ASxxxx Linker V03.00 + NoICE + sdld,  page 2.
 Hexadecimal  [32-Bits]
 
 Area                                    Addr        Size        Decimal Bytes (Attributes)
 --------------------------------        ----        ----        ------- ----- ------------
-_CODE                               00000800    00000264 =         612. bytes (REL,CON)
+_CODE                               00000800    000000FD =         253. bytes (REL,CON)
 
       Value  Global                              Global Defined In Module
       -----  --------------------------------   ------------------------
      00000800  __clock                            crt0
      00000804  _exit                              crt0
      0000080A  _main                              main
-     0000084D  _usart_set_baudrate                usart
-     00000881  _usart_set_parity                  usart
-     000008D5  _usart_set_stop_bits               usart
-     00000902  _usart_word_length                 usart
-     0000091B  _usart_set_autoflow                usart
-     00000955  _usart_init                        usart
-     0000097E  _usart_transmit                    usart
-     00000999  _usart_receive                     usart
-     0000099E  _usart_write                       usart
-     000009E5  _usart_read                        usart
+     0000082D  __pio_data                         pio
+     00000847  __pio_control                      pio
+     00000861  _pio_set_mode                      pio
+     0000089D  _pio_set_interrupts                pio
+     000008B0  _pio_set_interrupts_mask           pio
+     000008D7  _pio_read                          pio
+     000008ED  _pio_write                         pio
 
 ASxxxx Linker V03.00 + NoICE + sdld,  page 3.
 Hexadecimal  [32-Bits]
@@ -161,7 +158,7 @@ Hexadecimal  [32-Bits]
 
 Area                                    Addr        Size        Decimal Bytes (Attributes)
 --------------------------------        ----        ----        ------- ----- ------------
-_INITIALIZER                        00000A64    00000002 =           2. bytes (REL,CON)
+_INITIALIZER                        000008FD    00000004 =           4. bytes (REL,CON)
 
       Value  Global                              Global Defined In Module
       -----  --------------------------------   ------------------------
@@ -170,18 +167,18 @@ Hexadecimal  [32-Bits]
 
 Area                                    Addr        Size        Decimal Bytes (Attributes)
 --------------------------------        ----        ----        ------- ----- ------------
-_GSINIT                             00000A66    00000006 =           6. bytes (REL,CON)
+_GSINIT                             00000901    00000006 =           6. bytes (REL,CON)
 
       Value  Global                              Global Defined In Module
       -----  --------------------------------   ------------------------
-     00000A66  gsinit                             crt0
+     00000901  gsinit                             crt0
 
 ASxxxx Linker V03.00 + NoICE + sdld,  page 14.
 Hexadecimal  [32-Bits]
 
 Area                                    Addr        Size        Decimal Bytes (Attributes)
 --------------------------------        ----        ----        ------- ----- ------------
-_GSFINAL                            00000A6C    00000001 =           1. bytes (REL,CON)
+_GSFINAL                            00000907    00000001 =           1. bytes (REL,CON)
 
       Value  Global                              Global Defined In Module
       -----  --------------------------------   ------------------------
@@ -190,7 +187,7 @@ Hexadecimal  [32-Bits]
 
 Area                                    Addr        Size        Decimal Bytes (Attributes)
 --------------------------------        ----        ----        ------- ----- ------------
-_INITIALIZED                        00002000    00000002 =           2. bytes (REL,CON)
+_INITIALIZED                        00002000    00000004 =           4. bytes (REL,CON)
 
       Value  Global                              Global Defined In Module
       -----  --------------------------------   ------------------------
@@ -200,7 +197,11 @@ Files Linked                              [ module(s) ]
 
 build/crt0.rel                            [ crt0 ]
 build/main.rel                            [ main ]
-build/usart.rel                           [ usart ]
+
+
+Libraries Linked                          [ object file ]
+
+../../drivers/build/drivers.a             [ pio.rel ]
 
 ASxxxx Linker V03.00 + NoICE + sdld,  page 17.
 
diff --git a/sw/z80_tests/usart/build/sample.noi b/sw/z80/tests/pio/build/pio_test.noi
index 6d97288..3ddefe7 100644
--- a/sw/z80_tests/usart/build/sample.noi
+++ b/sw/z80/tests/pio/build/pio_test.noi
@@ -27,34 +27,31 @@ DEF l__HEADER4 0x2
 DEF l__HEADER5 0x2
 DEF l__HEADER6 0x2
 DEF l__HEADER7 0x2
-DEF l__INITIALIZED 0x2
-DEF l__INITIALIZER 0x2
 DEF l__HEADER0 0x3
+DEF l__INITIALIZED 0x4
+DEF l__INITIALIZER 0x4
 DEF l__GSINIT 0x6
 DEF l__HEADER8 0xC
-DEF l__CODE 0x264
+DEF l__CODE 0xFD
 DEF s__CODE 0x800
-DEF s__HOME 0xA64
-DEF s__INITIALIZER 0xA64
-DEF s__GSINIT 0xA66
-DEF s__GSFINAL 0xA6C
+DEF s__HOME 0x8FD
+DEF s__INITIALIZER 0x8FD
+DEF s__GSINIT 0x901
+DEF s__GSFINAL 0x907
 DEF s__DATA 0x2000
 DEF s__INITIALIZED 0x2000
-DEF s__BSEG 0x2002
-DEF s__BSS 0x2002
-DEF s__HEAP 0x2002
+DEF s__BSEG 0x2004
+DEF s__BSS 0x2004
+DEF s__HEAP 0x2004
 DEF __clock 0x800
 DEF _exit 0x804
 DEF _main 0x80A
-DEF _usart_set_baudrate 0x84D
-DEF _usart_set_parity 0x881
-DEF _usart_set_stop_bits 0x8D5
-DEF _usart_word_length 0x902
-DEF _usart_set_autoflow 0x91B
-DEF _usart_init 0x955
-DEF _usart_transmit 0x97E
-DEF _usart_receive 0x999
-DEF _usart_write 0x99E
-DEF _usart_read 0x9E5
-DEF gsinit 0xA66
-LOAD build/sample.ihx
+DEF __pio_data 0x82D
+DEF __pio_control 0x847
+DEF _pio_set_mode 0x861
+DEF _pio_set_interrupts 0x89D
+DEF _pio_set_interrupts_mask 0x8B0
+DEF _pio_read 0x8D7
+DEF _pio_write 0x8ED
+DEF gsinit 0x901
+LOAD build/pio_test.ihx
diff --git a/sw/z80_tests/usart/crt0.s b/sw/z80/tests/pio/crt0.s
index c272f06..c272f06 100644
--- a/sw/z80_tests/usart/crt0.s
+++ b/sw/z80/tests/pio/crt0.s
diff --git a/sw/z80/tests/pio/main.c b/sw/z80/tests/pio/main.c
new file mode 100644
index 0000000..4b0bcdb
--- /dev/null
+++ b/sw/z80/tests/pio/main.c
@@ -0,0 +1,12 @@
+#include "pio.h"
+
+void main(void)
+{
+    uint8_t j = 0;
+
+    pio_set_mode(PIO_A, PIO_MODE_BYTE_OUT, 0);
+
+    while (1) {
+        pio_write(PIO_A, j++);
+    }
+}
diff --git a/sw/z80_tests/usart/makefile b/sw/z80/tests/pio/makefile
index 080f41c..bd9d5bf 100644
--- a/sw/z80_tests/usart/makefile
+++ b/sw/z80/tests/pio/makefile
@@ -1,13 +1,13 @@
 ####
 # source code settings
 #
-OSNAME := sample
+NAME := pio_test
  
-CSOURCES 	:=  $(wildcard *.c)
+CSOURCES 	:= $(wildcard *.c)
 
 OBJECTS 	:= $(patsubst %.c,build/%.rel,$(CSOURCES))
-HEXFILE		:= build/$(OSNAME).hex
-BINARY  	:= build/$(OSNAME).bin
+HEXFILE		:= build/$(NAME).hex
+BINARY  	:= build/$(NAME).bin
 
 ### 
 # compiler settings
@@ -15,12 +15,18 @@ BINARY  	:= build/$(OSNAME).bin
 CC 		:= sdcc
 
 CFLAGS	:= -mz80 \
+			-pedantic \
 			-I . \
+			-I ../../arch \
+			-I ../../drivers/include \
 			-DDEBUG
 
-LDFLAGS := -mz80 --no-std-crt0 build/crt0.rel \
-			--std-c89 -pedantic \
-			--code-loc 0x0800 --data-loc 0x2000
+LDFLAGS := -mz80 \
+			-L ../../drivers/build/ \
+			-l drivers.a \
+			--no-std-crt0 build/crt0.rel \
+			--code-loc 0x0800 \
+			--data-loc 0x2000
 
 .PHONY: dirs dis clean
 all: $(BINARY)
@@ -28,8 +34,6 @@ all: $(BINARY)
 # build binary
 $(BINARY): $(OBJECTS) dirs
 	$(CC) $(LDFLAGS) $(OBJECTS) -o $(HEXFILE)
-	@# xxd -r -p $(HEXFILE) $(BINARY)
-	@# makebin -s 16384 $(HEXFILE) $(BINARY)
 	makebin -s 8192 $(HEXFILE) $(BINARY)
 
 $(OBJECTS): build/%.rel : %.c $(CSOURCES) dirs build/crt0.rel
diff --git a/sw/z80_tests/ram/build/crt0.rel b/sw/z80/tests/ram/build/crt0.rel
index cce6a25..b9ed132 100644
--- a/sw/z80_tests/ram/build/crt0.rel
+++ b/sw/z80/tests/ram/build/crt0.rel
@@ -1,5 +1,5 @@
 XL2
-H 14 areas 3 global symbols
+H 15 areas 3 global symbols
 M crt0
 S _main Ref0000
 S .__.ABS. Def0000
@@ -14,7 +14,8 @@ A _HEADER4 size 2 flags 8 addr 20
 A _HEADER5 size 2 flags 8 addr 28
 A _HEADER6 size 2 flags 8 addr 30
 A _HEADER7 size 2 flags 8 addr 38
-A _HEADER8 size 9 flags 8 addr 100
+A _HEADER8 size 2 flags 8 addr 66
+A _HEADER9 size 9 flags 8 addr 100
 A _HOME size 0 flags 0 addr 0
 A _INITIALIZER size 0 flags 0 addr 0
 A _GSINIT size 0 flags 0 addr 0
@@ -27,7 +28,7 @@ A _HEAP size 0 flags 0 addr 0
 T 00 00
 R 00 00 02 00
 T 00 00 C3 00 01
-R 00 00 02 00 00 03 0A 00
+R 00 00 02 00 00 03 0B 00
 T 08 00
 R 00 00 03 00
 T 08 00 ED 4D
@@ -56,12 +57,16 @@ T 38 00
 R 00 00 09 00
 T 38 00 ED 4D
 R 00 00 09 00
-T 00 01
+T 66 00
 R 00 00 0A 00
-T 00 01
+T 66 00 ED 4D
 R 00 00 0A 00
+T 00 01
+R 00 00 0B 00
+T 00 01
+R 00 00 0B 00
 T 00 01 31 FF FF CD 00 00 C3 00 00
-R 00 00 0A 00 02 06 00 00 00 09 00 00
+R 00 00 0B 00 02 06 00 00 00 09 00 00
 T 00 00
 R 00 00 00 00
 T 00 00
diff --git a/sw/z80_tests/ram/build/main.asm b/sw/z80/tests/ram/build/main.asm
index f3b8add..f3b8add 100644
--- a/sw/z80_tests/ram/build/main.asm
+++ b/sw/z80/tests/ram/build/main.asm
diff --git a/sw/z80_tests/ram/build/main.lst b/sw/z80/tests/ram/build/main.lst
index 17142d4..17142d4 100644
--- a/sw/z80_tests/ram/build/main.lst
+++ b/sw/z80/tests/ram/build/main.lst
diff --git a/sw/z80_tests/ram/build/main.rel b/sw/z80/tests/ram/build/main.rel
index cad7a3c..cad7a3c 100644
--- a/sw/z80_tests/ram/build/main.rel
+++ b/sw/z80/tests/ram/build/main.rel
diff --git a/sw/z80_tests/ram/build/main.sym b/sw/z80/tests/ram/build/main.sym
index d81bdc8..d81bdc8 100644
--- a/sw/z80_tests/ram/build/main.sym
+++ b/sw/z80/tests/ram/build/main.sym
diff --git a/sw/z80/tests/ram/build/ram_test.lk b/sw/z80/tests/ram/build/ram_test.lk
new file mode 100644
index 0000000..724eb89
--- /dev/null
+++ b/sw/z80/tests/ram/build/ram_test.lk
@@ -0,0 +1,11 @@
+-mjwx
+-i build/ram_test.hex
+-b _CODE = 0x0000
+-b _DATA = 0x2000
+-k /usr/libexec/../share/sdcc/lib/z80
+-k /usr/share/sdcc/lib/z80
+-l z80
+build/crt0.rel
+build/main.rel
+
+-e
diff --git a/sw/z80/tests/ram/build/ram_test.map b/sw/z80/tests/ram/build/ram_test.map
new file mode 100644
index 0000000..0d36247
--- /dev/null
+++ b/sw/z80/tests/ram/build/ram_test.map
@@ -0,0 +1,174 @@
+ASxxxx Linker V03.00 + NoICE + sdld,  page 1.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+.  .ABS.                            00000000    00000000 =           0. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+     00000000  .__.ABS.                           main
+     00000000  l__BSEG                         
+     00000000  l__BSS                          
+     00000000  l__CABS                         
+     00000000  l__DABS                         
+     00000000  l__DATA                         
+     00000000  l__GSFINAL                      
+     00000000  l__GSINIT                       
+     00000000  l__HEADER                       
+     00000000  l__HEAP                         
+     00000000  l__HOME                         
+     00000000  l__INITIALIZED                  
+     00000000  l__INITIALIZER                  
+     00000000  s__CABS                         
+     00000000  s__CODE                         
+     00000000  s__DABS                         
+     00000000  s__HEADER                       
+     00000000  s__HEADER0                      
+     00000000  s__HEADER1                      
+     00000000  s__HEADER2                      
+     00000000  s__HEADER3                      
+     00000000  s__HEADER4                      
+     00000000  s__HEADER5                      
+     00000000  s__HEADER6                      
+     00000000  s__HEADER7                      
+     00000000  s__HEADER8                      
+     00000000  s__HEADER9                      
+     00000002  l__HEADER1                      
+     00000002  l__HEADER2                      
+     00000002  l__HEADER3                      
+     00000002  l__HEADER4                      
+     00000002  l__HEADER5                      
+     00000002  l__HEADER6                      
+     00000002  l__HEADER7                      
+     00000002  l__HEADER8                      
+     00000003  l__HEADER0                      
+     00000009  l__HEADER9                      
+     0000000D  l__CODE                         
+     0000000D  s__GSFINAL                      
+     0000000D  s__GSINIT                       
+     0000000D  s__HOME                         
+     0000000D  s__INITIALIZER                  
+     00002000  s__BSEG                         
+     00002000  s__BSS                          
+     00002000  s__DATA                         
+     00002000  s__HEAP                         
+     00002000  s__INITIALIZED                  
+
+ASxxxx Linker V03.00 + NoICE + sdld,  page 2.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_CODE                               00000000    0000000D =          13. bytes (REL,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+     00000000  _exit                              crt0
+     00000003  _main                              main
+
+ASxxxx Linker V03.00 + NoICE + sdld,  page 3.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER0                            00000000    00000003 =           3. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 4.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER1                            00000000    00000002 =           2. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 5.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER2                            00000000    00000002 =           2. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 6.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER3                            00000000    00000002 =           2. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 7.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER4                            00000000    00000002 =           2. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 8.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER5                            00000000    00000002 =           2. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 9.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER6                            00000000    00000002 =           2. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 10.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER7                            00000000    00000002 =           2. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 11.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER8                            00000000    00000002 =           2. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 12.
+Hexadecimal  [32-Bits]
+
+Area                                    Addr        Size        Decimal Bytes (Attributes)
+--------------------------------        ----        ----        ------- ----- ------------
+_HEADER9                            00000000    00000009 =           9. bytes (ABS,CON)
+
+      Value  Global                              Global Defined In Module
+      -----  --------------------------------   ------------------------
+ASxxxx Linker V03.00 + NoICE + sdld,  page 13.
+
+Files Linked                              [ module(s) ]
+
+build/crt0.rel                            [ crt0 ]
+build/main.rel                            [ main ]
+
+ASxxxx Linker V03.00 + NoICE + sdld,  page 14.
+
+User Base Address Definitions
+
+_CODE = 0x0000
+_DATA = 0x2000
+
+
\ No newline at end of file
diff --git a/sw/z80/tests/ram/build/ram_test.noi b/sw/z80/tests/ram/build/ram_test.noi
new file mode 100644
index 0000000..94266c5
--- /dev/null
+++ b/sw/z80/tests/ram/build/ram_test.noi
@@ -0,0 +1,50 @@
+DEF .__.ABS. 0x0
+DEF l__BSEG 0x0
+DEF l__BSS 0x0
+DEF l__CABS 0x0
+DEF l__DABS 0x0
+DEF l__DATA 0x0
+DEF l__GSFINAL 0x0
+DEF l__GSINIT 0x0
+DEF l__HEADER 0x0
+DEF l__HEAP 0x0
+DEF l__HOME 0x0
+DEF l__INITIALIZED 0x0
+DEF l__INITIALIZER 0x0
+DEF s__CABS 0x0
+DEF s__CODE 0x0
+DEF s__DABS 0x0
+DEF s__HEADER 0x0
+DEF s__HEADER0 0x0
+DEF s__HEADER1 0x0
+DEF s__HEADER2 0x0
+DEF s__HEADER3 0x0
+DEF s__HEADER4 0x0
+DEF s__HEADER5 0x0
+DEF s__HEADER6 0x0
+DEF s__HEADER7 0x0
+DEF s__HEADER8 0x0
+DEF s__HEADER9 0x0
+DEF l__HEADER1 0x2
+DEF l__HEADER2 0x2
+DEF l__HEADER3 0x2
+DEF l__HEADER4 0x2
+DEF l__HEADER5 0x2
+DEF l__HEADER6 0x2
+DEF l__HEADER7 0x2
+DEF l__HEADER8 0x2
+DEF l__HEADER0 0x3
+DEF l__HEADER9 0x9
+DEF l__CODE 0xD
+DEF s__GSFINAL 0xD
+DEF s__GSINIT 0xD
+DEF s__HOME 0xD
+DEF s__INITIALIZER 0xD
+DEF s__BSEG 0x2000
+DEF s__BSS 0x2000
+DEF s__DATA 0x2000
+DEF s__HEAP 0x2000
+DEF s__INITIALIZED 0x2000
+DEF _exit 0x0
+DEF _main 0x3
+LOAD build/ram_test.ihx
diff --git a/sw/z80_tests/ram/build/test.lk b/sw/z80/tests/ram/build/test.lk
index 03a8db4..03a8db4 100644
--- a/sw/z80_tests/ram/build/test.lk
+++ b/sw/z80/tests/ram/build/test.lk
diff --git a/sw/z80_tests/ram/build/test.map b/sw/z80/tests/ram/build/test.map
index 07b953f..07b953f 100644
--- a/sw/z80_tests/ram/build/test.map
+++ b/sw/z80/tests/ram/build/test.map
diff --git a/sw/z80_tests/ram/build/test.noi b/sw/z80/tests/ram/build/test.noi
index 403beda..403beda 100644
--- a/sw/z80_tests/ram/build/test.noi
+++ b/sw/z80/tests/ram/build/test.noi
diff --git a/sw/z80_tests/ram/build/test.z80 b/sw/z80/tests/ram/build/test.z80
index 25a162a..25a162a 100644
--- a/sw/z80_tests/ram/build/test.z80
+++ b/sw/z80/tests/ram/build/test.z80
diff --git a/sw/z80_tests/ram/crt0.s b/sw/z80/tests/ram/crt0.s
index ac0698f..d775e66 100644
--- a/sw/z80_tests/ram/crt0.s
+++ b/sw/z80/tests/ram/crt0.s
@@ -21,7 +21,6 @@
 	.org	0x38
 	reti
     .org    0x66
-    ld hl,#BEEF
     reti
 
 	.org	0x100
diff --git a/sw/z80_tests/ram/main.c b/sw/z80/tests/ram/main.c
index 581072b..581072b 100644
--- a/sw/z80_tests/ram/main.c
+++ b/sw/z80/tests/ram/main.c
diff --git a/sw/z80_tests/ram/makefile b/sw/z80/tests/ram/makefile
index 35d7419..b8435a7 100644
--- a/sw/z80_tests/ram/makefile
+++ b/sw/z80/tests/ram/makefile
@@ -1,7 +1,7 @@
 ####
 # source code settings
 #
-OSNAME := test
+OSNAME := ram_test
  
 CSOURCES 	:=  $(wildcard *.c)
 
diff --git a/sw/z80_tests/usart/build/main.rel b/sw/z80_tests/usart/build/main.rel
deleted file mode 100644
index 2557016..0000000
--- a/sw/z80_tests/usart/build/main.rel
+++ /dev/null
@@ -1,41 +0,0 @@
-XL2
-H 9 areas 4 global symbols
-M main
-O -mz80
-S _usart_write Ref0000
-S .__.ABS. Def0000
-S _usart_init Ref0000
-A _CODE size 43 flags 0 addr 0
-S _main Def0000
-A _DATA size 0 flags 0 addr 0
-A _INITIALIZED size 0 flags 0 addr 0
-A _DABS size 0 flags 8 addr 0
-A _HOME size 0 flags 0 addr 0
-A _GSINIT size 0 flags 0 addr 0
-A _GSFINAL size 0 flags 0 addr 0
-A _INITIALIZER size 0 flags 0 addr 0
-A _CABS size 0 flags 8 addr 0
-T 00 00
-R 00 00 00 00
-T 00 00 21 0A 00 E5 2E 01 E5 2E 60 E5 CD 00 00 21
-R 00 00 00 00 02 0D 02 00
-T 0E 00 06 00 39 F9 21 0D 00 E5 21 2E 00 E5 CD
-R 00 00 00 00 00 0B 00 00
-T 1B 00 00 00 F1 F1
-R 00 00 00 00 02 02 00 00
-T 1F 00
-R 00 00 00 00
-T 1F 00 21 05 00 E5 21 3D 00 E5 CD 00 00 F1 F1 18
-R 00 00 00 00 00 07 00 00 02 0B 00 00
-T 2D 00 F1
-R 00 00 00 00
-T 2E 00
-R 00 00 00 00
-T 2E 00 48 65 6C 6C 6F 2C 20 57 6F 72 6C 64 21 0A
-R 00 00 00 00
-T 3C 00 00
-R 00 00 00 00
-T 3D 00
-R 00 00 00 00
-T 3D 00 64 6F 6E 65 0A 00
-R 00 00 00 00
diff --git a/sw/z80_tests/usart/build/pio.lst b/sw/z80_tests/usart/build/pio.lst
deleted file mode 100644
index fcafc2a..0000000
--- a/sw/z80_tests/usart/build/pio.lst
+++ /dev/null
@@ -1,194 +0,0 @@
-                              1 ;--------------------------------------------------------
-                              2 ; File Created by SDCC : free open source ANSI-C Compiler
-                              3 ; Version 3.6.0 #9615 (Linux)
-                              4 ;--------------------------------------------------------
-                              5 	.module pio
-                              6 	.optsdcc -mz80
-                              7 	
-                              8 ;--------------------------------------------------------
-                              9 ; Public variables in this module
-                             10 ;--------------------------------------------------------
-                             11 	.globl __pio_data
-                             12 	.globl __pio_control
-                             13 	.globl _pio_set_mode
-                             14 	.globl _pio_set_interrupts
-                             15 	.globl _pio_set_interrupts_mask
-                             16 ;--------------------------------------------------------
-                             17 ; special function registers
-                             18 ;--------------------------------------------------------
-                             19 ;--------------------------------------------------------
-                             20 ; ram data
-                             21 ;--------------------------------------------------------
-                             22 	.area _DATA
-                             23 ;--------------------------------------------------------
-                             24 ; ram data
-                             25 ;--------------------------------------------------------
-                             26 	.area _INITIALIZED
-   0000                      27 _pio_port:
-   0000                      28 	.ds 2
-   0002                      29 _pio_ctrl:
-   0002                      30 	.ds 2
-                             31 ;--------------------------------------------------------
-                             32 ; absolute external ram data
-                             33 ;--------------------------------------------------------
-                             34 	.area _DABS (ABS)
-                             35 ;--------------------------------------------------------
-                             36 ; global & static initialisations
-                             37 ;--------------------------------------------------------
-                             38 	.area _HOME
-                             39 	.area _GSINIT
-                             40 	.area _GSFINAL
-                             41 	.area _GSINIT
-                             42 ;--------------------------------------------------------
-                             43 ; Home
-                             44 ;--------------------------------------------------------
-                             45 	.area _HOME
-                             46 	.area _HOME
-                             47 ;--------------------------------------------------------
-                             48 ; code
-                             49 ;--------------------------------------------------------
-                             50 	.area _CODE
-                             51 ;pio.c:6: inline void _pio_data(int port, uint8_t data)
-                             52 ;	---------------------------------
-                             53 ; Function _pio_data
-                             54 ; ---------------------------------
-   0000                      55 __pio_data::
-                             56 ;pio.c:8: *(pio_port + port) = data;
-   0000 21 02 00      [10]   57 	ld	hl,#2
-   0003 39            [11]   58 	add	hl,sp
-   0004 FD 21r00r00   [14]   59 	ld	iy,#_pio_port
-   0008 FD 7E 00      [19]   60 	ld	a,0 (iy)
-   000B 86            [ 7]   61 	add	a, (hl)
-   000C 4F            [ 4]   62 	ld	c,a
-   000D FD 7E 01      [19]   63 	ld	a,1 (iy)
-   0010 23            [ 6]   64 	inc	hl
-   0011 8E            [ 7]   65 	adc	a, (hl)
-   0012 47            [ 4]   66 	ld	b,a
-   0013 21 04 00      [10]   67 	ld	hl, #4+0
-   0016 39            [11]   68 	add	hl, sp
-   0017 7E            [ 7]   69 	ld	a, (hl)
-   0018 02            [ 7]   70 	ld	(bc),a
-   0019 C9            [10]   71 	ret
-                             72 ;pio.c:11: inline void _pio_control(int port, uint8_t cmd)
-                             73 ;	---------------------------------
-                             74 ; Function _pio_control
-                             75 ; ---------------------------------
-   001A                      76 __pio_control::
-                             77 ;pio.c:13: *(pio_ctrl + port) = cmd;
-   001A 21 02 00      [10]   78 	ld	hl,#2
-   001D 39            [11]   79 	add	hl,sp
-   001E FD 21r02r00   [14]   80 	ld	iy,#_pio_ctrl
-   0022 FD 7E 00      [19]   81 	ld	a,0 (iy)
-   0025 86            [ 7]   82 	add	a, (hl)
-   0026 4F            [ 4]   83 	ld	c,a
-   0027 FD 7E 01      [19]   84 	ld	a,1 (iy)
-   002A 23            [ 6]   85 	inc	hl
-   002B 8E            [ 7]   86 	adc	a, (hl)
-   002C 47            [ 4]   87 	ld	b,a
-   002D 21 04 00      [10]   88 	ld	hl, #4+0
-   0030 39            [11]   89 	add	hl, sp
-   0031 7E            [ 7]   90 	ld	a, (hl)
-   0032 02            [ 7]   91 	ld	(bc),a
-   0033 C9            [10]   92 	ret
-                             93 ;pio.c:16: void pio_set_mode(int port, int mode, uint8_t io)
-                             94 ;	---------------------------------
-                             95 ; Function pio_set_mode
-                             96 ; ---------------------------------
-   0034                      97 _pio_set_mode::
-                             98 ;pio.c:19: _pio_control(port, ((mode << 6) | 0x0F));
-   0034 21 04 00      [10]   99 	ld	hl, #4+0
-   0037 39            [11]  100 	add	hl, sp
-   0038 7E            [ 7]  101 	ld	a, (hl)
-   0039 0F            [ 4]  102 	rrca
-   003A 0F            [ 4]  103 	rrca
-   003B E6 C0         [ 7]  104 	and	a,#0xc0
-   003D F6 0F         [ 7]  105 	or	a, #0x0f
-   003F 4F            [ 4]  106 	ld	c,a
-   0040 D1            [10]  107 	pop	de
-   0041 E1            [10]  108 	pop	hl
-   0042 E5            [11]  109 	push	hl
-   0043 D5            [11]  110 	push	de
-                            111 ;pio.c:13: *(pio_ctrl + port) = cmd;
-   0044 FD 2Ar02r00   [20]  112 	ld	iy,(_pio_ctrl)
-   0048 5D            [ 4]  113 	ld	e, l
-   0049 54            [ 4]  114 	ld	d, h
-   004A FD 19         [15]  115 	add	iy, de
-   004C FD 71 00      [19]  116 	ld	0 (iy), c
-                            117 ;pio.c:23: if (mode == PIO_MODE_BIT_IO) {
-   004F FD 21 04 00   [14]  118 	ld	iy,#4
-   0053 FD 39         [15]  119 	add	iy,sp
-   0055 FD 7E 00      [19]  120 	ld	a,0 (iy)
-   0058 D6 03         [ 7]  121 	sub	a, #0x03
-   005A C0            [11]  122 	ret	NZ
-   005B FD 7E 01      [19]  123 	ld	a,1 (iy)
-   005E B7            [ 4]  124 	or	a, a
-   005F C0            [11]  125 	ret	NZ
-                            126 ;pio.c:24: _pio_control(port, io);
-   0060 FD 21 06 00   [14]  127 	ld	iy,#6
-   0064 FD 39         [15]  128 	add	iy,sp
-   0066 FD 4E 00      [19]  129 	ld	c,0 (iy)
-                            130 ;pio.c:13: *(pio_ctrl + port) = cmd;
-   0069 ED 5Br02r00   [20]  131 	ld	de,(_pio_ctrl)
-   006D 19            [11]  132 	add	hl,de
-   006E 71            [ 7]  133 	ld	(hl),c
-                            134 ;pio.c:24: _pio_control(port, io);
-   006F C9            [10]  135 	ret
-                            136 ;pio.c:28: void pio_set_interrupts(int port, int control)
-                            137 ;	---------------------------------
-                            138 ; Function pio_set_interrupts
-                            139 ; ---------------------------------
-   0070                     140 _pio_set_interrupts::
-                            141 ;pio.c:31: _pio_control(port, (control | 0x07));
-   0070 21 04 00      [10]  142 	ld	hl, #4+0
-   0073 39            [11]  143 	add	hl, sp
-   0074 7E            [ 7]  144 	ld	a, (hl)
-   0075 F6 07         [ 7]  145 	or	a, #0x07
-   0077 4F            [ 4]  146 	ld	c,a
-   0078 D1            [10]  147 	pop	de
-   0079 E1            [10]  148 	pop	hl
-   007A E5            [11]  149 	push	hl
-   007B D5            [11]  150 	push	de
-                            151 ;pio.c:13: *(pio_ctrl + port) = cmd;
-   007C ED 5Br02r00   [20]  152 	ld	de,(_pio_ctrl)
-   0080 19            [11]  153 	add	hl,de
-   0081 71            [ 7]  154 	ld	(hl),c
-                            155 ;pio.c:31: _pio_control(port, (control | 0x07));
-   0082 C9            [10]  156 	ret
-                            157 ;pio.c:34: void pio_set_interrupts_mask(int port, int control, uint8_t mask)
-                            158 ;	---------------------------------
-                            159 ; Function pio_set_interrupts_mask
-                            160 ; ---------------------------------
-   0083                     161 _pio_set_interrupts_mask::
-                            162 ;pio.c:38: _pio_control(port, (control | 0x17));
-   0083 21 04 00      [10]  163 	ld	hl, #4+0
-   0086 39            [11]  164 	add	hl, sp
-   0087 7E            [ 7]  165 	ld	a, (hl)
-   0088 F6 17         [ 7]  166 	or	a, #0x17
-   008A 4F            [ 4]  167 	ld	c,a
-   008B D1            [10]  168 	pop	de
-   008C E1            [10]  169 	pop	hl
-   008D E5            [11]  170 	push	hl
-   008E D5            [11]  171 	push	de
-                            172 ;pio.c:13: *(pio_ctrl + port) = cmd;
-   008F FD 2Ar02r00   [20]  173 	ld	iy,(_pio_ctrl)
-   0093 5D            [ 4]  174 	ld	e, l
-   0094 54            [ 4]  175 	ld	d, h
-   0095 FD 19         [15]  176 	add	iy, de
-   0097 FD 71 00      [19]  177 	ld	0 (iy), c
-                            178 ;pio.c:39: _pio_control(port, mask);
-   009A FD 21 06 00   [14]  179 	ld	iy,#6
-   009E FD 39         [15]  180 	add	iy,sp
-   00A0 FD 4E 00      [19]  181 	ld	c,0 (iy)
-                            182 ;pio.c:13: *(pio_ctrl + port) = cmd;
-   00A3 ED 5Br02r00   [20]  183 	ld	de,(_pio_ctrl)
-   00A7 19            [11]  184 	add	hl,de
-   00A8 71            [ 7]  185 	ld	(hl),c
-                            186 ;pio.c:39: _pio_control(port, mask);
-   00A9 C9            [10]  187 	ret
-                            188 	.area _CODE
-                            189 	.area _INITIALIZER
-   0000                     190 __xinit__pio_port:
-   0000 00 42               191 	.dw #0x4200
-   0002                     192 __xinit__pio_ctrl:
-   0002 02 42               193 	.dw #0x4202
-                            194 	.area _CABS (ABS)
diff --git a/sw/z80_tests/usart/build/sample.z80 b/sw/z80_tests/usart/build/sample.z80
deleted file mode 100644
index 965a0d8..0000000
--- a/sw/z80_tests/usart/build/sample.z80
+++ /dev/null
@@ -1,558 +0,0 @@
-;
-;  DZ80 V3.4.1 Z80 Disassembly of build/sample.bin
-;  2017/09/25 17:08
-;
-	org	0x0
-;
-X0000:	jp	X0100
-;
-	org	0x4
-;
-X0004:	rst	0x38
-X0005:	rst	0x38
-X0006:	rst	0x38
-;
-	org	0x8
-;
-	reti
-;
-X000a:	rst	0x38
-;
-	org	0xc
-;
-X000c:	rst	0x38
-X000d:	rst	0x38
-;
-	org	0x10
-;
-	reti
-;
-	rst	0x38
-;
-	org	0x18
-;
-	reti
-;
-	rst	0x38
-;
-	org	0x20
-;
-	reti
-;
-	rst	0x38
-;
-	org	0x28
-;
-	reti
-;
-	rst	0x38
-;
-	org	0x30
-;
-	reti
-;
-	rst	0x38
-;
-	org	0x38
-;
-	reti
-;
-	rst	0x38
-;
-	org	0x100
-;
-X0100:	ld	sp,X0000
-	call	X0b15
-	call	X08b4
-	jp	X0804
-;
-	org	0x800
-;
-	ld	a,0x2
-	rst	8
-	ret
-;
-X0804:	ld	a,0x0
-	rst	8
-X0807:	halt
-;
-	jr	X0807
-;
-	ld	hl,X0002
-	add	hl,sp
-	ld	iy,X2000
-	ld	a,(iy+0x0)
-	add	a,(hl)
-	ld	c,a
-	ld	a,(iy+0x1)
-	inc	hl
-	adc	a,(hl)
-	ld	b,a
-	ld	hl,X0004
-	add	hl,sp
-	ld	a,(hl)
-	ld	(bc),a
-	ret
-;
-	ld	hl,X0002
-	add	hl,sp
-	ld	iy,X2002
-	ld	a,(iy+0x0)
-	add	a,(hl)
-	ld	c,a
-	ld	a,(iy+0x1)
-	inc	hl
-	adc	a,(hl)
-	ld	b,a
-	ld	hl,X0004
-	add	hl,sp
-	ld	a,(hl)
-	ld	(bc),a
-	ret
-;
-	ld	hl,X0004
-	add	hl,sp
-	ld	a,(hl)
-	rrca
-	rrca
-	and	0xc0
-	or	0xf
-	ld	c,a
-	pop	de
-	pop	hl
-	push	hl
-	push	de
-	ld	iy,(X2002)
-	ld	e,l
-	ld	d,h
-	add	iy,de
-	ld	(iy+0x0),c
-	ld	iy,X0004
-	add	iy,sp
-	ld	a,(iy+0x0)
-	sub	0x3
-	ret	nz
-	ld	a,(iy+0x1)
-	or	a
-	ret	nz
-	ld	iy,X0006
-	add	iy,sp
-	ld	c,(iy+0x0)
-	ld	de,(X2002)
-	add	hl,de
-	ld	(hl),c
-	ret
-;
-	ld	hl,X0004
-	add	hl,sp
-	ld	a,(hl)
-	or	0x7
-	ld	c,a
-	pop	de
-	pop	hl
-	push	hl
-	push	de
-	ld	de,(X2002)
-	add	hl,de
-	ld	(hl),c
-	ret
-;
-	ld	hl,X0004
-	add	hl,sp
-	ld	a,(hl)
-	or	0x17
-	ld	c,a
-	pop	de
-	pop	hl
-	push	hl
-	push	de
-	ld	iy,(X2002)
-	ld	e,l
-	ld	d,h
-	add	iy,de
-	ld	(iy+0x0),c
-	ld	iy,X0006
-	add	iy,sp
-	ld	c,(iy+0x0)
-	ld	de,(X2002)
-	add	hl,de
-	ld	(hl),c
-	ret
-;
-X08b4:	ld	hl,X000a
-	push	hl
-	ld	l,0x1
-	push	hl
-	ld	l,0x60
-	push	hl
-	call	X0a00
-	ld	hl,X0006
-	add	hl,sp
-	ld	sp,hl
-	ld	hl,X000d
-	push	hl
-	ld	hl,X08e2
-	push	hl
-	call	X0a49
-	pop	af
-	pop	af
-X08d3:	ld	hl,X0005
-	push	hl
-	ld	hl,X08f1
-	push	hl
-	call	X0a49
-	pop	af
-	pop	af
-	jr	X08d3
-;
-X08e2:	ld	c,b
-	ld	h,l
-	ld	l,h
-	ld	l,h
-	ld	l,a
-	inc	l
-	jr	nz,X0941
-	ld	l,a
-	ld	(hl),d
-	ld	l,h
-	ld	h,h
-	ld	hl,X000a
-X08f1:	ld	h,h
-	ld	l,a
-	ld	l,(hl)
-	ld	h,l
-	ld	a,(bc)
-	nop
-	ret
-;
-X08f8:	push	ix
-	ld	ix,X0000
-	add	ix,sp
-	ld	hl,(X2004)
-	ld	bc,X0004
-	add	hl,bc
-	ld	a,(hl)
-	or	0x80
-	ld	(hl),a
-	ld	hl,(X2004)
-	ld	c,(ix+0x4)
-	ld	(hl),c
-	ld	de,(X2004)
-	inc	de
-	ld	l,(ix+0x5)
-	ld	h,0x0
-	ld	a,(hl)
-	ld	(de),a
-	ld	hl,(X2004)
-	ld	bc,X0004
-	add	hl,bc
-	ld	a,(hl)
-	and	0x7f
-	ld	(hl),a
-	pop	ix
-	ret
-;
-X092c:	ld	hl,(X2004)
-	ld	bc,X0004
-	add	hl,bc
-	ld	iy,X0002
-	add	iy,sp
-	ld	a,(iy+0x0)
-	dec	a
-	jr	nz,X094b
-	ld	a,(iy+0x1)
-	or	a
-	jr	nz,X094b
-	ld	a,(hl)
-	or	0x10
-	ld	(hl),a
-	jr	X0962
-;
-X094b:	ld	iy,X0002
-	add	iy,sp
-	ld	a,(iy+0x0)
-	sub	0x2
-	jr	nz,X0962
-	ld	a,(iy+0x1)
-	or	a
-	jr	nz,X0962
-	ld	a,(hl)
-	and	0xef
-	ld	(hl),a
-X0962:	ld	hl,(X2004)
-	ld	bc,X0004
-	add	hl,bc
-	ld	iy,X0002
-	add	iy,sp
-	ld	a,(iy+0x0)
-	rlca
-	rlca
-	rlca
-	and	0xf8
-	and	0x8
-	ld	c,a
-	ld	a,(hl)
-	and	0xf7
-	or	c
-	ld	(hl),a
-	ret
-;
-X0980:	ld	bc,(X2004)
-	inc	bc
-	inc	bc
-	inc	bc
-	inc	bc
-	ld	iy,X0002
-	add	iy,sp
-	ld	a,(iy+0x0)
-	sub	0xa
-	jr	nz,X099f
-	ld	a,(iy+0x1)
-	or	a
-	jr	nz,X099f
-	ld	a,0x1
-	jr	X09a0
-;
-X099f:	xor	a
-X09a0:	xor	0x1
-	add	a,a
-	add	a,a
-	and	0x4
-	ld	l,a
-	ld	a,(bc)
-	and	0xfb
-	or	l
-	ld	(bc),a
-	ret
-;
-	ld	hl,(X2004)
-	ld	bc,X0004
-	add	hl,bc
-	ld	iy,X0002
-	add	iy,sp
-	ld	a,(iy+0x0)
-	and	0x3
-	ld	c,a
-	ld	a,(hl)
-	and	0xfc
-	or	c
-	ld	(hl),a
-	ret
-;
-X09c6:	ld	hl,(X2004)
-	ld	bc,X000c
-	add	hl,bc
-	ld	iy,X0002
-	add	iy,sp
-	ld	a,(iy+0x0)
-	and	0x1
-	ld	c,a
-	ld	a,(hl)
-	and	0xfe
-	or	c
-	ld	(hl),a
-	ld	hl,(X2004)
-	ld	bc,X0005
-	add	hl,bc
-	ld	a,(iy+0x0)
-	sub	0x3
-	jr	nz,X09f6
-	ld	a,(iy+0x1)
-	or	a
-	jr	nz,X09f6
-	ld	a,0x1
-	jr	X09f7
-;
-X09f6:	xor	a
-X09f7:	and	0x1
-	ld	c,a
-	ld	a,(hl)
-	and	0xfe
-	or	c
-	ld	(hl),a
-	ret
-;
-X0a00:	pop	bc
-	pop	hl
-	push	hl
-	push	bc
-	push	hl
-	call	X08f8
-	pop	af
-	ld	hl,X0004
-	add	hl,sp
-	ld	c,(hl)
-	inc	hl
-	ld	b,(hl)
-	push	bc
-	call	X092c
-	pop	af
-	ld	hl,X0006
-	add	hl,sp
-	ld	c,(hl)
-	inc	hl
-	ld	b,(hl)
-	push	bc
-	call	X0980
-	ld	hl,X0000
-	ex	(sp),hl
-	call	X09c6
-	pop	af
-	ret
-;
-	ld	hl,(X2004)
-	ld	iy,X0002
-	add	iy,sp
-	ld	a,(iy+0x0)
-	ld	(hl),a
-X0a36:	ld	hl,(X2004)
-	ld	bc,X000d
-	add	hl,bc
-	ld	a,(hl)
-	rlca
-	rlca
-	rlca
-	jr	nc,X0a36
-	ret
-;
-	ld	hl,(X2004)
-	ld	l,(hl)
-	ret
-;
-X0a49:	push	ix
-	ld	ix,X0000
-	add	ix,sp
-	push	af
-	ld	a,(ix+0x4)
-	ld	(ix+0xfe),a
-	ld	a,(ix+0x5)
-	ld	(ix+0xff),a
-	ld	c,(ix+0x6)
-	ld	b,(ix+0x7)
-X0a64:	ld	e,c
-	ld	d,b
-	dec	bc
-	ld	a,d
-	or	e
-	jr	z,X0a89
-	ld	de,(X2004)
-	pop	hl
-	push	hl
-	ld	a,(hl)
-	inc	(ix+0xfe)
-	jr	nz,X0a7a
-	inc	(ix+0xff)
-X0a7a:	ld	(de),a
-X0a7b:	ld	hl,(X2004)
-	ld	de,X000d
-	add	hl,de
-	ld	a,(hl)
-	rlca
-	rlca
-	jr	nc,X0a64
-	jr	X0a7b
-;
-X0a89:	ld	l,c
-	ld	h,b
-	ld	sp,ix
-	pop	ix
-	ret
-;
-	push	ix
-	ld	ix,X0000
-	add	ix,sp
-	ld	hl,Xfffa
-	add	hl,sp
-	ld	sp,hl
-	ld	a,(ix+0x4)
-	ld	(ix+0xfa),a
-	ld	a,(ix+0x5)
-	ld	(ix+0xfb),a
-	ld	c,(ix+0x6)
-	ld	b,(ix+0x7)
-	ld	(ix+0xfc),0x0
-	ld	(ix+0xfd),0x0
-X0ab7:	ld	e,c
-	ld	d,b
-	dec	bc
-	ld	a,d
-	or	e
-	jr	z,X0b06
-	ld	hl,(X2004)
-	ld	e,(hl)
-	pop	hl
-	push	hl
-	ld	(hl),e
-	inc	(ix+0xfa)
-	jr	nz,X0acd
-	inc	(ix+0xfb)
-X0acd:	ld	de,(X2004)
-	ld	hl,X000d
-	add	hl,de
-	ld	(ix+0xfe),l
-	ld	(ix+0xff),h
-	ld	l,(ix+0xfe)
-	ld	h,(ix+0xff)
-	ld	a,(hl)
-	rrca
-	rrca
-	rrca
-	and	0x1
-	jr	nz,X0af6
-	ld	l,(ix+0xfe)
-	ld	h,(ix+0xff)
-	ld	a,(hl)
-	rrca
-	rrca
-	and	0x1
-	jr	z,X0afc
-X0af6:	pop	hl
-	push	hl
-	dec	hl
-	ex	(sp),hl
-	jr	X0ab7
-;
-X0afc:	inc	(ix+0xfc)
-	jr	nz,X0ab7
-	inc	(ix+0xfd)
-	jr	X0ab7
-;
-X0b06:	pop	bc
-	pop	hl
-	push	hl
-	push	bc
-	ld	sp,ix
-	pop	ix
-	ret
-;
-X0b0f:	nop
-	ld	b,d
-	ld	(bc),a
-	ld	b,d
-	nop
-	ld	b,b
-X0b15:	ld	bc,X0006
-	ld	a,b
-	or	c
-	jr	z,X0b24
-	ld	de,X2000
-	ld	hl,X0b0f
-	ldir
-X0b24:	ret
-;
-	rst	0x38
-;
-;	Miscellaneous equates
-;
-;  These are addresses referenced in the code but
-;  which are in the middle of a multibyte instruction
-;  or are addresses outside the initialized space
-;
-X0002	equ	0x2
-X2002	equ	0x2002
-X2004	equ	0x2004
-Xfffa	equ	0xfffa
-;
-	end
-;
-
diff --git a/sw/z80_tests/usart/main.c b/sw/z80_tests/usart/main.c
deleted file mode 100644
index d2e1d8e..0000000
--- a/sw/z80_tests/usart/main.c
+++ /dev/null
@@ -1,11 +0,0 @@
-#include "usart.h"
-
-void main(void)
-{
-    usart_init(USART_BAUDRATE_1200, USART_PARITY_EVEN, USART_STOP_BITS_1);
-    usart_write("Hello, World!\n", 13);
-
-    while(1) {
-        usart_write("done\n", 5);
-    }
-}
diff --git a/sw/z80_tests/usart/usart.c b/sw/z80_tests/usart/usart.c
deleted file mode 120000
index 2927470..0000000
--- a/sw/z80_tests/usart/usart.c
+++ /dev/null
@@ -1 +0,0 @@
-../../z80/kernel/drivers/usart.c
\ No newline at end of file
diff --git a/sw/z80_tests/usart/usart.h b/sw/z80_tests/usart/usart.h
deleted file mode 120000
index 84ee24d..0000000
--- a/sw/z80_tests/usart/usart.h
+++ /dev/null
@@ -1 +0,0 @@
-../../z80/kernel/include/drivers/usart.h
\ No newline at end of file