Move sw to sw-old and hw to hw-altium, add kicad files

52 files changed, 2643 insertions, 0 deletions

diff --git a/sw-old/z80/TODO.txt b/sw-old/z80/TODO.txt
new file mode 100644
index 0000000..67be671
--- /dev/null
+++ b/sw-old/z80/TODO.txt
@@ -0,0 +1 @@
+- fix kernel makefile (currently broken)
diff --git a/sw-old/z80/arch/include/addresses.h b/sw-old/z80/arch/include/addresses.h
new file mode 100644
index 0000000..32f1997
--- /dev/null
+++ b/sw-old/z80/arch/include/addresses.h
@@ -0,0 +1,15 @@
+#ifndef __ADDRESSES_H__
+#define __ADDRESSES_H__
+
+#define ADDR_DEV_ROM_L      0x0000
+#define ADDR_DEV_ROM_H      0x2000
+
+#define ADDR_DEV_PIO        0x0010
+#define ADDR_DEV_CTC        0x0020
+#define ADDR_DEV_USART      0x0030
+
+#define ADDR_DEV_MMU
+
+#define ADDR_DEV_RAM        0x8000
+
+#endif
diff --git a/sw-old/z80/arch/include/sleep.h b/sw-old/z80/arch/include/sleep.h
new file mode 100644
index 0000000..bd4214b
--- /dev/null
+++ b/sw-old/z80/arch/include/sleep.h
@@ -0,0 +1,14 @@
+#ifndef __SLEEP_H__
+#define __SLEEP_H__
+
+#ifndef F_CPU
+#error undefined CPU clock speed
+#endif
+
+#define SLEEP_UNIT ((F_CPU/4)/2)
+
+#include <stdint.h>
+
+void usleep(uint16_t microseconds);
+
+#endif // __SLEEP_H__
\ No newline at end of file
diff --git a/sw-old/z80/arch/makefile b/sw-old/z80/arch/makefile
new file mode 100644
index 0000000..2763c10
--- /dev/null
+++ b/sw-old/z80/arch/makefile
@@ -0,0 +1,27 @@
+# Drivers library
+
+LIB     := build/arch.a
+SOURCES := $(wildcard *.c)
+OBJECTS := $(patsubst %.c,build/%.rel,$(SOURCES))
+
+F_CPU := 10000
+
+CC := sdcc
+AR := sdar
+CFLAGS := -mz80 \
+			-Iinclude \
+			-DDEBUG \
+			-DF_CPU=$(F_CPU)
+
+.PHONY: dirs clean
+$(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-old/z80/arch/sleep.c b/sw-old/z80/arch/sleep.c
new file mode 100644
index 0000000..154e7ec
--- /dev/null
+++ b/sw-old/z80/arch/sleep.c
@@ -0,0 +1,16 @@
+#include "sleep.h"
+
+void usleep(uint16_t microseconds)
+{
+    __asm
+    pop hl
+loop:
+    ld bc, #SLEEP_UNIT
+unit:
+    nop
+    dec bc
+    jr nz, unit
+    dec hl
+    jr nz,loop
+    __endasm;
+}
\ No newline at end of file
diff --git a/sw-old/z80/drivers/ctc.c b/sw-old/z80/drivers/ctc.c
new file mode 100644
index 0000000..5ac4254
--- /dev/null
+++ b/sw-old/z80/drivers/ctc.c
@@ -0,0 +1,6 @@
+#include "ctc.h"
+
+void ctc_control()
+{
+
+}
diff --git a/sw-old/z80/drivers/include/ctc.h b/sw-old/z80/drivers/include/ctc.h
new file mode 100644
index 0000000..80e8b4b
--- /dev/null
+++ b/sw-old/z80/drivers/include/ctc.h
@@ -0,0 +1,6 @@
+#ifndef __CTC_H__
+#define __CTC_H__
+
+void ctc_control();
+
+#endif /* __CTC_H__ */
diff --git a/sw-old/z80/drivers/include/pio.h b/sw-old/z80/drivers/include/pio.h
new file mode 100644
index 0000000..ee968d7
--- /dev/null
+++ b/sw-old/z80/drivers/include/pio.h
@@ -0,0 +1,52 @@
+#ifndef __PIO_H__
+#define __PIO_H__
+
+#include "addresses.h"
+#include <stdint.h>
+
+// DEBUG
+#define PIO_ASM_INTERFACE
+
+// ports
+#define PIO_A       0
+#define PIO_B       1
+
+// registers
+#define PIO_REG_DATA 0
+#define PIO_REG_CTRL 2
+
+#define PIO_REG_DATA_A 0    // (PIO_A | PIO_REG_PORT)
+#define PIO_REG_DATA_B 1    // (PIO_B | PIO_REG_PORT)
+#define PIO_REG_CTRL_A 2    // (PIO_A | PIO_REG_CTRL)
+#define PIO_REG_CTRL_B 3    // (PIO_B | PIO_REG_CTRL)
+
+#define PIO_MODE_BYTE_OUT  0 // mode 0
+#define PIO_MODE_BYTE_IN   1 // mode 1
+#define PIO_MODE_BYTE_BI   2 // mode 2
+#define PIO_MODE_BIT_IO    3 // mode 3
+
+#define PIO_INT_DISABLE         0 
+#define PIO_INT_ACTIVE_HIGH     2 
+#define PIO_INT_AND_MODE        4
+#define PIO_INT_ENABLE          8
+
+/* functions used internally to interface with the device */
+inline void _pio_write(uint8_t reg, uint8_t data);
+inline uint8_t _pio_read(uint8_t reg);
+
+/* 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);
+void pio_set_interrupts_mask(int port, int control, uint8_t mask);
+
+// uint8_t pio_read_data(int port);
+uint8_t pio_read(int port);
+void pio_write(int port, uint8_t data);
+
+inline int pio_read_pin(int port, uint8_t pin);
+inline void pio_write_pin(int port, uint8_t pin);
+
+// TODO: implement mode (in/out/both) and interrupt vector
+
+#endif /* __PIO_H__ */
diff --git a/sw-old/z80/drivers/include/usart.h b/sw-old/z80/drivers/include/usart.h
new file mode 100644
index 0000000..05aeb4a
--- /dev/null
+++ b/sw-old/z80/drivers/include/usart.h
@@ -0,0 +1,158 @@
+#ifndef __USART_H__
+#define __USART_H__
+
+#include "addresses.h"
+
+#include <stdint.h>
+#include <string.h>
+
+// baudrate clock divisors
+// values from TL16C550C datasheet (table 9 for 1.8432 MHz crystal)
+#define USART_BAUDRATE_50       2304
+#define USART_BAUDRATE_75       1536
+#define USART_BAUDRATE_110      1047
+#define USART_BAUDRATE_134_5    857
+#define USART_BAUDRATE_150      768
+#define USART_BAUDRATE_300      384
+#define USART_BAUDRATE_600      192
+#define USART_BAUDRATE_1200     96
+#define USART_BAUDRATE_1800     64
+#define USART_BAUDRATE_2000     58
+#define USART_BAUDRATE_2400     48
+#define USART_BAUDRATE_3600     32
+#define USART_BAUDRATE_4800     24
+#define USART_BAUDRATE_7200     16
+#define USART_BAUDRATE_9600     12
+#define USART_BAUDRATE_19200    6
+#define USART_BAUDRATE_38400    3
+#define USART_BAUDRATE_56000    3
+
+// parity
+#define USART_PARITY_NONE       0
+#define USART_PARITY_EVEN       1
+#define USART_PARITY_ODD        2
+
+// stop bits
+#define USART_STOP_BITS_1       10
+#define USART_STOP_BITS_15      15
+#define USART_STOP_BITS_2       20
+
+// word lenght
+#define USART_WORD_LENGTH_5     0
+#define USART_WORD_LENGTH_6     1
+#define USART_WORD_LENGTH_7     2
+#define USART_WORD_LENGTH_8     3
+
+// autoflow
+#define USART_AUTOFLOW_ALL      3
+#define USART_AUTOFLOW_CTS      2
+#define USART_AUTOFLOW_OFF      0
+
+typedef unsigned int        uint;
+typedef volatile uint8_t    register_t;
+
+/* stuctures for usart registers */
+struct IER 
+{
+    volatile uint received_data_interrupt :1;
+    volatile uint transmitter_empty_interrupt :1;
+    volatile uint receiver_line_status_interrupt :1;
+    volatile uint modem_status_interrupt :1;
+    volatile uint reserved :4;
+};
+
+struct IIR
+{
+    volatile uint interrupt_pending :1;
+    volatile uint interrupt_id :3;
+    volatile uint reserved :2;
+    volatile uint fifos :2;
+};
+
+struct FCR
+{
+    volatile uint fifo_enable :1;
+    volatile uint receiver_fifo_rst :1;
+    volatile uint trasmitter_fifo_rst :1;
+    volatile uint dma_mode_select :1;
+    volatile uint reserved :1;
+    volatile uint receiver_trigger :2;
+};
+
+struct LCR
+{
+    volatile uint word_length :2;
+    volatile uint stop_bits :1;
+    volatile uint parity :1;
+    volatile uint even_parity :1;
+    volatile uint stick_parity :1;
+    volatile uint break_control :1;
+    volatile uint divisor_latch_access :1;
+};
+
+struct MCR
+{
+    volatile uint data_terminal_ready :1;
+    volatile uint request_to_send :1;
+    volatile uint out1;
+    volatile uint out2;
+    volatile uint loop;
+    volatile uint autoflow :1;
+    volatile uint reserved :2;
+};
+
+struct LSR 
+{
+    volatile uint data_ready :1;
+    volatile uint overrun_error :1;
+    volatile uint parity_error :1;
+    volatile uint framing_error :1;
+    volatile uint break_interrupt :1;
+    volatile uint transmitter_holder_empty :1;
+    volatile uint transmitter_empty :1;
+    volatile uint fifo_recv_error :1;
+};
+
+struct MSR
+{
+    volatile uint delta_cts :1;
+    volatile uint delta_data_set_ready :1;
+    volatile uint trailing_edge_ring_indicator :1;
+    volatile uint delta_data_carrier_detect :1;
+    volatile uint clear_to_send :1;
+    volatile uint data_set_ready :1;
+    volatile uint ring_indicator :1;
+    volatile uint data_carrier_detect :1;
+};
+
+/* this structure is only for internal use */
+struct _usart_device
+{
+    register_t buffer;  // also used as LSB for divisor latch
+    struct IER IER;
+    struct IIR IIR;
+    struct FCR FCR;
+    struct LCR LCR;
+    struct MCR MCR;
+    struct LSR LSR;
+    struct MSR MSR;
+    register_t scratch;
+};
+
+
+// setup functions (wrappers)
+void usart_set_baudrate(uint16_t baudrate);
+void usart_set_parity(int mode);
+void usart_set_stop_bits(int count);
+void usart_set_word_length(int length);
+void usart_set_autoflow(int mode);
+
+inline void usart_init(uint16_t baudrate, int parity, int stop_bits); 
+
+void usart_transmit(uint8_t data);
+uint8_t usart_receive();
+
+int usart_write(uint8_t *data, size_t size);
+int usart_read(uint8_t *buffer, size_t count);
+
+#endif // __USART__H__
diff --git a/sw-old/z80/drivers/makefile b/sw-old/z80/drivers/makefile
new file mode 100644
index 0000000..65ded58
--- /dev/null
+++ b/sw-old/z80/drivers/makefile
@@ -0,0 +1,24 @@
+# Drivers library
+
+LIB     := build/drivers.a
+SOURCES := $(wildcard *.c)
+OBJECTS := $(patsubst %.c,build/%.rel,$(SOURCES))
+
+CC := sdcc
+AR := sdar
+CFLAGS := -mz80 -Iinclude -I../arch/include -DDEBUG
+
+.PHONY: dirs rebuild clean
+$(LIB): $(OBJECTS)
+	$(AR) vrcs $@ $(OBJECTS)
+
+$(OBJECTS): build/%.rel: %.c $(SOURCES) dirs
+	$(CC) $(CFLAGS) -c $< -o $@
+
+rebuild: clean $(LIB)
+
+dirs:
+	mkdir -p build
+
+clean:
+	- rm -rd build
diff --git a/sw-old/z80/drivers/pio.c b/sw-old/z80/drivers/pio.c
new file mode 100644
index 0000000..f396e43
--- /dev/null
+++ b/sw-old/z80/drivers/pio.c
@@ -0,0 +1,84 @@
+#include "pio.h"
+
+#ifdef PIO_ASM_INTERFACE
+// TODO: set inline
+void _pio_write(uint8_t reg, uint8_t data)
+{
+    __asm
+    ;;  pop function arguments data in h, reg in a (l)
+    pop hl
+    ld a, l
+    ;; add ADDR_DEV_PIO to get the device address
+    add a, #ADDR_DEV_PIO
+    ld c, a
+    ;; load data
+    out (c), h
+    __endasm;
+}
+
+inline uint8_t _pio_read(uint8_t reg)
+{
+    // TODO: check "dec sp"
+    __asm
+    ;; pop function argument
+    dec sp
+    pop hl
+    ld a, l
+    ;; add ADDR_DEV_PIO to get the device address
+    add a, #ADDR_DEV_PIO
+    ld c, a
+    ;; read data
+    in l, (c)
+    ret
+    __endasm;
+}
+
+#else
+
+inline void _pio_write(uint8_t reg, uint8_t data)
+{
+    *((uint8_t *) (ADDR_DEV_PIO + reg)) = data;
+}
+
+inline uint8_t _pio_read(uint8_t reg)
+{
+    return *((uint8_t *) (ADDR_DEV_PIO + reg));
+}
+
+#endif
+
+void pio_set_mode(int port, int mode, uint8_t io)
+{
+    // 0x0F is a control sequence to set mode
+    _pio_write((PIO_REG_CTRL + port), ((mode << 6) | 0x0F));
+
+    // this mode requires an additional argument that sets
+    // a mode for each pin
+    if (mode == PIO_MODE_BIT_IO) {
+        _pio_write((PIO_REG_CTRL + port), io);
+    }
+}
+
+void pio_set_interrupts(int port, int control)
+{
+    // 0x07 is a control sequence to set interrupts
+    _pio_write((PIO_REG_CTRL + port), (control<<4 | 0x07));
+}
+
+void pio_set_interrupts_mask(int port, int control, uint8_t mask)
+{
+    // 0x17 is a control sequence to set interrupts
+    // AND interpret the next byte as a bitmask
+    _pio_write((PIO_REG_CTRL + port),(control | 0x97));
+    _pio_write((PIO_REG_CTRL + port), mask);
+}
+
+uint8_t pio_read(int port)
+{
+    return _pio_read((PIO_REG_DATA + port));
+}
+
+void pio_write(int port, uint8_t data)
+{
+    _pio_write((PIO_REG_DATA + port), data);
+}
diff --git a/sw-old/z80/drivers/usart.c b/sw-old/z80/drivers/usart.c
new file mode 100644
index 0000000..9a5ee38
--- /dev/null
+++ b/sw-old/z80/drivers/usart.c
@@ -0,0 +1,91 @@
+#include "usart.h"
+
+static volatile struct _usart_device *_usart = ((struct _usart_device *) ADDR_DEV_USART);
+
+void usart_set_baudrate(uint16_t baudrate)
+{
+    // enable latch access
+    _usart->LCR.divisor_latch_access = 1;
+    _usart->buffer = 0x00FF & baudrate; // LSBs
+    memcpy(&_usart->IER, &(baudrate >>8), 1);
+    // _usart->IER    = 0x00FF & (baudrate >> 8); // MSBs
+    _usart->LCR.divisor_latch_access = 0;
+}
+
+void usart_set_parity(int mode)
+{
+    if (mode == USART_PARITY_EVEN) {
+        _usart->LCR.even_parity = 1;
+    }
+    else if (mode == USART_PARITY_ODD) {
+        _usart->LCR.even_parity = 0;
+    }
+
+     _usart->LCR.parity = (mode == USART_PARITY_NONE) ? 0 : 1;
+}
+
+void usart_set_stop_bits(int count)
+{
+    _usart->LCR.stop_bits = (count == USART_STOP_BITS_1) ? 0 : 1;
+}
+
+void usart_word_length(int length)
+{
+    _usart->LCR.word_length = length;
+}
+
+void usart_set_autoflow(int mode)
+{
+    _usart->MCR.autoflow = (mode == USART_AUTOFLOW_OFF) ? 0 : 1;
+    _usart->MCR.data_terminal_ready = (mode == USART_AUTOFLOW_ALL);
+}
+
+inline void usart_init(uint16_t baudrate, int parity, int stop_bits)
+{
+    usart_set_baudrate(baudrate);
+    usart_set_parity(parity);
+    usart_set_stop_bits(stop_bits);
+    usart_set_autoflow(USART_AUTOFLOW_OFF);
+}
+
+void usart_transmit(uint8_t data)
+{
+    _usart->buffer = data;
+    while (_usart->LSR.transmitter_holder_empty == 0); // wait
+}
+
+uint8_t usart_receive()
+{
+    return _usart->buffer;
+}
+
+int usart_write(uint8_t *data, size_t size)
+{
+    uint8_t *dp = data;
+
+    while (size--) {
+        _usart->buffer = *(dp++);
+        while (_usart->LSR.transmitter_empty);
+    }
+
+    // TODO: do something that actually counts for sent bytes 
+    return size;
+}
+
+int usart_read(uint8_t *buffer, size_t count)
+{
+    uint8_t *bp = buffer;
+    size_t read_count = 0;
+
+    while (count--) {
+        *(bp++) = _usart->buffer;
+        // check for errors
+        if (_usart->LSR.framing_error || _usart->LSR.parity_error) {
+            bp--; // delete last byte (?)
+        } else {
+            read_count++;
+        }
+    }
+
+    return read_count;
+}
diff --git a/sw-old/z80/kernel/crt0.s b/sw-old/z80/kernel/crt0.s
new file mode 100644
index 0000000..00c7da1
--- /dev/null
+++ b/sw-old/z80/kernel/crt0.s
@@ -0,0 +1,103 @@
+;--------------------------------------------------------------------------
+;  crt0.s - Generic crt0.s for a Z80
+;
+;  Copyright (C) 2000, Michael Hope
+;
+;  This library is free software; you can redistribute it and/or modify it
+;  under the terms of the GNU General Public License as published by the
+;  Free Software Foundation; either version 2, or (at your option) any
+;  later version.
+;
+;  This library is distributed in the hope that it will be useful,
+;  but WITHOUT ANY WARRANTY; without even the implied warranty of
+;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;  GNU General Public License for more details.
+;
+;  You should have received a copy of the GNU General Public License 
+;  along with this library; see the file COPYING. If not, write to the
+;  Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
+;   MA 02110-1301, USA.
+;
+;  As a special exception, if you link this library with other files,
+;  some of which are compiled with SDCC, to produce an executable,
+;  this library does not by itself cause the resulting executable to
+;  be covered by the GNU General Public License. This exception does
+;  not however invalidate any other reasons why the executable file
+;   might be covered by the GNU General Public License.
+;--------------------------------------------------------------------------
+
+	.module crt0
+	.globl	_kmain
+
+	.area	_HEADER (ABS)
+	;; Reset vector
+	.org 	0
+	jp	init
+
+	.org	0x08
+	reti
+	.org	0x10
+	reti
+	.org	0x18
+	reti
+	.org	0x20
+	reti
+	.org	0x28
+	reti
+	.org	0x30
+	reti
+	.org	0x38
+	reti
+
+	.org	0x100
+init:
+	;; Set stack pointer directly above top of memory.
+	ld	sp,#0xFFFF
+
+	;; Initialise global variables
+	call	gsinit
+	call	_kmain
+	jp	    _exit
+
+	;; Ordering of segments for the linker.
+	.area	_HOME
+	.area	_CODE
+	.area	_INITIALIZER
+	.area   _GSINIT
+	.area   _GSFINAL
+
+	.area	_DATA
+	.area	_INITIALIZED
+	.area	_BSEG
+	.area   _BSS
+	.area   _HEAP
+
+	.area   _CODE
+
+__clock::
+	ld	a,#2
+	rst	0x08
+	ret
+
+_exit::
+	;; Exit - special code to the emulator
+	ld	a,#0
+	rst	0x08
+1$:
+	halt
+	jr	1$
+
+	.area   _GSINIT
+gsinit::
+	; ld	bc, #l__INITIALIZER
+	ld	a, b
+	or	a, c
+	jr	Z, gsinit_next
+	; ld	de, #s__INITIALIZED
+	; ld	hl, #s__INITIALIZER
+	ldir
+gsinit_next:
+
+	.area   _GSFINAL
+	ret
+
diff --git a/sw-old/z80/kernel/fs/fd.c b/sw-old/z80/kernel/fs/fd.c
new file mode 100644
index 0000000..96603ad
--- /dev/null
+++ b/sw-old/z80/kernel/fs/fd.c
@@ -0,0 +1,255 @@
+#include "fs/fd.h"
+#include "fs/fdop.h"
+#include "fs/fs.h"
+
+/* from fd.h */
+struct file_desc fd_table[FD_TABLE_SIZE];
+struct uint8_t  fd_bmap[FD_TABLE_SIZE / 8];
+
+/* File descriptors implementation */
+
+int8_t open(const char *path, uint8_t flags)
+{
+    // TODO
+    return 0; 
+}
+
+size_t ls(int8_t fd, struct dirent *buf, uint8_t all)
+{
+    // TODO
+    return 0; 
+}
+
+size_t find(int8_t fd, struct dirent *buf, const char *name)
+{
+    // TODO
+    return 0; 
+}
+
+int8_t mkdir(int8_t fd, const char *name)
+{
+    // TODO
+    return 0; 
+}
+
+int8_t touch(int8_t fd, const char *name)
+{
+    // TODO
+    return 0; 
+}
+
+int8_t ln(int8_t fd, const char *name)
+{
+    // TODO
+    return 0; 
+}
+
+int8_t seek(int8_t fd, fsize_t pos)
+{
+    // TODO
+    return 0; 
+}
+
+size_t readline(int8_t fd, char *buf, char term)
+{
+    // TODO
+    return 0; 
+}
+
+int8_t print(int8_t fd, const char *str)
+{
+    // TODO
+    return 0; 
+}
+
+size_t read(int8_t fd, void *buf, size_t n)
+{
+    // TODO
+    return 0; 
+}
+
+int8_t write(int8_t fd, const void *buf, size_t n)
+{
+    // TODO
+    return 0; 
+}
+
+void close(int8_t fd)
+{
+    // TODO
+    return 0; 
+}
+
+/* Set of file descriptors operations */
+/* Determines if to use the serial interface or the address space */
+
+/* Address space section */
+
+/* File functions */
+
+size_t as_readline(inode_t inode, fsize_t seek, char *buf, char term)
+{
+    // TODO
+    return 0;
+}
+
+size_t as_print(inode_t inode, fsize_t seek, const char *str)
+{
+    // TODO
+    return 0;
+}
+
+size_t as_append(inode_t inode, fsize_t *seek_ptr, const char *str)
+{
+    // TODO
+    return 0;
+}
+
+size_t as_read(inode_t inode, fsize_t seek, void *buf, size_t n)
+{
+    // TODO
+    return 0;
+}
+
+size_t as_write(inode_t inode, fsize_t seek, const void *buf, size_t n)
+{
+    // TODO
+    return 0;
+}
+
+size_t as_bin_append(inode_t inode, fsize_t *seek_ptr, const void *buf, size_t
+n)
+{
+    // TODO
+    return 0;
+}
+
+/* Directory functions */
+
+size_t as_ls(inode_t inode, struct dirent *buf, uint8_t all)
+{
+    // TODO
+    return 0;
+}
+
+size_t as_find(inode_t inode, struct dirent *buf, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t as_mkdir(inode_t inode, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t as_rmdir(inode_t inode, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t as_touch(inode_t inode, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t as_rm(inode_t inode, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t as_ln(inode_t inode, const char *path, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+/* Serial Space section */
+/* Warning, it doesn't switch to the right driver */
+
+/* File functions */
+
+size_t ss_readline(inode_t inode, fsize_t seek, char *buf, char term)
+{
+    // TODO
+    return 0;
+}
+
+size_t ss_print(inode_t inode, fsize_t seek, const char *str)
+{
+    // TODO
+    return 0;
+}
+
+size_t ss_append(inode_t inode, fsize_t *seek_ptr, const char *str)
+{
+    // TODO
+    return 0;
+}
+
+size_t ss_read(inode_t inode, fsize_t seek, void *buf, size_t n)
+{
+    // TODO
+    return 0;
+}
+
+size_t ss_write(inode_t inode, fsize_t seek, const void *buf, size_t n)
+{
+    // TODO
+    return 0;
+}
+
+size_t ss_bin_append(inode_t inode, fsize_t *seek_ptr, const void *buf, size_t
+n)
+{
+    // TODO
+    return 0;
+}
+
+/* Directory functions */
+
+size_t ss_ls(inode_t inode, struct dirent *buf, uint8_t all)
+{
+    // TODO
+    return 0;
+}
+
+size_t ss_find(inode_t inode, struct dirent *buf, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t ss_mkdir(inode_t inode, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t ss_rmdir(inode_t inode, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t ss_touch(inode_t inode, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t ss_rm(inode_t inode, const char *name)
+{
+    // TODO
+    return 0;
+}
+
+int8_t ss_ln(inode_t, const char *path, const char *name)
+{
+    // TODO
+    return 0;
+}
diff --git a/sw-old/z80/kernel/fs/fs.c b/sw-old/z80/kernel/fs/fs.c
new file mode 100644
index 0000000..584f934
--- /dev/null
+++ b/sw-old/z80/kernel/fs/fs.c
@@ -0,0 +1,236 @@
+#include "fs/fs.h"
+#include "fs/users.h"
+#include "fs/dev.h"
+
+/* from users.h */
+struct fs_user c_user;
+
+/* from inode.h */
+inode_t c_inode;
+
+struct fs_dev devices[FS_MOUNT_LIMIT];
+
+/* filesystem basic implementation */
+
+devsize_t fs_block(blk_t block)
+{
+    // TODO
+    return 0;
+}
+
+devsize_t fs_inode(struct fs_inode *buf)
+{
+    struct fs_superblock * sb;
+    devsize_t seek;
+
+    if (FS_USE_ROM(c_inode))
+    {
+        seek = FS_ROM_SPACE;
+        sb = (struct fs_superblock*) seek; 
+
+    } else {
+
+        seek = 0;
+
+        if (c_inode.dev > 0x7)
+            panic("Invalid device");    // TODO, still to implement
+
+        sb = &devices[c_inode.dev].superblock; 
+    }
+
+    if (c_inode.inode >= sb->imap_size)
+    {
+        // TODO, set errno
+        return 0;   // inode doesn't exist
+    }
+
+    seek += sizeof(struct fs_superblock) + 
+            sizeof(struct fs_inode) * c_inode.inode;
+
+    if (FS_USE_ROM(c_inode))
+        *buf = *(struct fs_inode*)seek;
+    else
+    {
+        /* set sio port */
+        sio_port = devices[c_inode.dev].port_no;
+        sio_seek = seek;
+
+        if (sio_read((void *)buf, INODE_META_SIZE) < INODE_META_SIZE)
+        {
+            // TODO, set errno
+            return 0;   // cannot read to device
+        }
+    }
+
+    return seek + INODE_META_SIZE;
+}
+
+/* from fd.h */
+int8_t __fd_new()
+{
+    int8_t fd;
+    for (int8_t = 0; i < FD_TABLE_SIZE / 8; i++)
+    {
+        for (uint8_t bit = 0x80, j = 0; bit > 0; bit >>= 1, j++)
+        {
+            if (!(bit & fd_bmap[i]))
+                return i * 8 + j;
+        }
+    }
+
+    return -1;
+}
+
+/* from fd.h */
+int8_t __open_c_inode(uint8_t flags)
+{
+    /* read meta data */
+    struct fs_inode inode;
+
+    /* init file_desc buffer */
+    struct file_desc desc = {c_inode, 0};
+    
+    desc.begin = fs_inode(&inode);
+    
+    /* bind operations */
+
+    if (flags & OPEN_DIR)
+    {
+        /* dir handler */
+
+        if (inode.type == INODE_TYPE_DIR)
+        {
+            /* bind dir functions */
+            if (FS_USE_ROM(c_inode))
+                /* bind address space functions */
+                FD_BIND_AS_DIR(desc.opers)
+            else
+                /* bind serial space functions */
+                FD_BIND_SS_DIR(desc.opers)
+
+        } else {
+
+            // TODO, set errno
+            return -1;  // not a directory
+        }
+
+    } else if (flags & OPEN_LINK) {
+        
+        /* link handler */
+
+        if (inode.type == INODE_TYPE_LINK)
+        {
+            if (FS_USE_ROM(c_inode))
+                FD_BIND_AS_FILE(desc.opers, flags)
+            else
+                FD_BIND_SS_FILE(desc.opers, flags)
+
+            if (flags & OPEN_ERASE)
+                /* empty file content */
+                __inode_empty(desc.begin);
+
+        } else {
+            
+            // TODO, set errno
+            return -1;  // not a link
+        }
+
+    } else {
+
+        /* file */
+
+        if (inode.type == INODE_TYPE_FILE)
+            ;   // do nothing
+        else if (inode.type == INODE_TYPE_SPECIAL) {
+            
+            // TODO, bind special callbacks
+            
+        } else {
+
+            // TODO, set errno
+            return -1;
+        }
+
+        /* bind operations */
+
+        if (FS_USE_ROM(c_inode))
+        {
+            if (flags & OPEN_BIN)
+                FD_BIND_AS_BINFILE(desc.opers, flags)
+            else
+                FD_BIND_AS_FILE(desc.opers, flags) 
+
+        } else {
+            
+            if (flags & OPEN_BIN)
+                FD_BIND_SS_BINFILE(desc.opers, flags)
+            else
+                FD_BIND_SS_FILE(desc.opers, flags)
+        }
+    }
+
+    /* find a free fd space */
+    
+    int8_t fd = __fd_new();
+
+    if (fd < 0)
+    {
+        // TODO, set errno, fd not available
+
+    } else
+        fd_table[fd] = desc; // copy buffer into the table
+
+    return fd;
+}
+
+inode_t fs_rec_path(const char *path);
+
+inode_t fs_parse_path(const char *path)
+{
+    inode_t ino, cwd = c_inode;
+
+    switch (path[0])
+    {
+        case '0':
+        FS_INODE_NULL(ino)
+        return ino;
+
+        case '/':
+        FS_INODE_ROOT(ino)
+        c_inode = ino;       // set cwd to root
+        path++;
+        break;
+
+        case '~':
+
+        if (path[1] = '/')
+        {
+            c_inode.dev = FS_DEV_ROM;
+            c_inode.inode = c_user.home;  // set cwd to home
+            path += 2;
+        }
+            
+        break;
+   }
+
+   ino = fs_rec_path(path);
+   c_inode = cwd;
+   return ino;
+}
+
+inode_t fs_rec_path(const char *path)
+{
+    devsize_t inode = fs_inode(c_inode.inode); 
+    inode_t rel;
+
+    if (!inode)   // if not exists
+    {
+        FS_INODE_NULL(rel)
+        return rel;
+    }
+
+    // TODO, check if dir or file
+    // TODO, if dir, find name
+    // TODO, set fs_cwd to new inode
+    // TODO, recall fs_rec_path
+}
diff --git a/sw-old/z80/kernel/include/devices.h b/sw-old/z80/kernel/include/devices.h
new file mode 100644
index 0000000..a846f9b
--- /dev/null
+++ b/sw-old/z80/kernel/include/devices.h
@@ -0,0 +1,15 @@
+#ifndef __DEVICES_H__
+#define __DEVICES_H__
+
+#define ADDR_DEV_ROM_L      0x0000
+#define ADDR_DEV_ROM_H      0x2000
+
+#define ADDR_DEV_USART      0x4000
+#define ADDR_DEV_CTC        0x4100
+#define ADDR_DEV_PIO        0x4200
+
+#define ADDR_DEV_MMU
+
+#define ADDR_DEV_RAM        0x8000
+
+#endif
diff --git a/sw-old/z80/kernel/include/errno.h b/sw-old/z80/kernel/include/errno.h
new file mode 100644
index 0000000..7632269
--- /dev/null
+++ b/sw-old/z80/kernel/include/errno.h
@@ -0,0 +1,35 @@
+#ifndef ERRNO_H
+#define ERRNO_H
+
+extern int errno;
+
+#define EPERM       1       /* Operation not permitted */
+#define ENOENT      2       /* No such file or directory */
+#define ESRCH       3       /* No such process */
+#define EINTR       4       /* Interrupted system call */
+#define EIO         5       /* Input/output error */
+#define ENXIO       6       /* Device not configured */
+#define E2BIG       7       /* Argument list too long */
+#define ENOEXEC     8       /* Exec format error */
+#define EBADF       9       /* Bad file descriptor */
+#define ECHILD      10      /* No child processes */
+#define EDEADLK     11      /* Resource deadlock avoided */
+
+#define ENOMEM      12      /* Cannot allocate memory */
+#define EACCES      13      /* Permission denied */
+#define EFAULT      14      /* Bad address */
+
+#define ENOTBLK     15      /* Block device required */
+#define EBUSY       16      /* Device busy */
+#define EEXIST      17      /* File exists */
+
+#define EXDEV       18      /* Cross-device link */
+#define ENODEV      19      /* Operation not supported by device */
+#define ENOTDIR     20      /* Not a directory */
+#define EISDIR      21      /* Is a directory */
+#define EINVAL      22      /* Invalid argument */
+#define ENFILE      23      /* Too many open files in system */
+#define EMFILE      24      /* Too many open files */
+#define ENOTTY      25      /* Inappropriate ioctl for device */
+
+#endif
diff --git a/sw-old/z80/kernel/include/fs/dev.h b/sw-old/z80/kernel/include/fs/dev.h
new file mode 100644
index 0000000..8e550f3
--- /dev/null
+++ b/sw-old/z80/kernel/include/fs/dev.h
@@ -0,0 +1,29 @@
+#ifndef DEV_H
+#define DEV_H
+
+#include "types.h"
+
+#define FS_MOUNT_LIMIT 16
+
+struct fs_superblock
+{
+    uint8_t     magic;           // identifier
+
+    size_t      blk_size;           // size of a single block
+    size_t      imap_size;          // quantity of inodes
+    size_t      dmap_size;          // quantity of blocks
+};
+
+struct fs_dev
+{
+    uint                    enabled :1;     // in use
+    uint                    port_no :3;     // serial port number
+    uint                            :4; 
+    inode_t                 inode;          // dir mounted
+    struct fs_superblock    superblock;     // block informations
+};
+
+/* list of devices */ 
+extern struct fs_dev devices[FS_MOUNT_LIMIT];
+
+#endif
diff --git a/sw-old/z80/kernel/include/fs/dirent.h b/sw-old/z80/kernel/include/fs/dirent.h
new file mode 100644
index 0000000..2fd224a
--- /dev/null
+++ b/sw-old/z80/kernel/include/fs/dirent.h
@@ -0,0 +1,17 @@
+#ifndef __DIRENT_H__
+#define __DIRENT_H__
+
+#include "types.h"
+
+struct dirent
+{
+    ino_t       inode;       // inode referred
+    uint8_t     name_size;    // size of the name
+    char        name[];         // name of the referred inode
+};
+
+/* if inode is FS_INO_NULL, then the dirent is a memory leak */
+/* Warning: dirent leaks are generated by rm or rmdir operations */
+/* Filesystem must be periodically checked and cleaned */
+
+#endif  // __DIRENT_H__
diff --git a/sw-old/z80/kernel/include/fs/fd.h b/sw-old/z80/kernel/include/fs/fd.h
new file mode 100644
index 0000000..d2fea2a
--- /dev/null
+++ b/sw-old/z80/kernel/include/fs/fd.h
@@ -0,0 +1,102 @@
+#ifndef __FD_H__
+#define __FD_H__
+
+#include "types.h"
+
+#define FD_MAX 32
+
+#define OPEN_READ       0x1
+#define OPEN_WRITE      0x2 
+#define OPEN_BIN        0x4
+#define OPEN_APPEND     0x8
+#define OPEN_ERASE      0x10
+#define OPEN_DIR        0x20
+#define OPEN_LINK       0x40
+
+#define LS_ALL       0x1
+
+/* declare dirent, not include */
+#ifndef __DIRENT_H__
+struct dirent;
+#endif
+
+/* set of operations callback for fd */
+struct fd_operations
+{
+    size_t (*readline)(inode_t, fsize_t, char *, char term);
+    size_t (*print)(inode_t, fsize_t, const char *);
+    size_t (*append)(inode_t, fsize_t*, const char *);
+
+    size_t (*read)(inode_t, fsize_t, void *, size_t);
+    size_t (*write)(inode_t, fsize_t, const void *, size_t);
+    size_t (*bin_append)(inode_t, fsize_t*, const void *, size_t);
+
+    size_t (*ls)(inode_t, struct dirent *, uint8_t);
+    size_t (*find)(inode_t, struct dirent *, const char *);
+    int8_t (*mkdir)(inode_t, const char *);
+    int8_t (*rmdir)(inode_t, const char *);
+    int8_t (*touch)(inode_t, const char *);
+    int8_t (*rm)(inode_t, const char *);
+    int8_t (*ln)(inode_t, const char *, const char *);
+
+    int8_t (*special)(inode_t, void *, size_t);
+};
+
+/* file descriptor */
+struct file_desc
+{
+    inode_t                 inode;  // inode pointed
+    fsize_t                 seek;   // virtual seek
+    devsize_t               begin;  // beginning of blocks
+    struct fd_operations    opers;  // bound operations
+};
+
+/* bitmap of used file descriptors */
+extern struct uint8_t fd_bmap[FD_TABLE_SIZE / 8];
+
+/* table of file descriptors */
+extern struct file_desc fd_table[FD_TABLE_SIZE];
+
+/* returns a free file descriptor */
+int8_t __fd_new();
+
+/* opens a file streaming of the cwd */
+int8_t __open_c_inode(uint8_t flags);
+
+/* opens a file streaming by a path */
+int8_t open(const char *path, uint8_t flags); 
+
+/* list content of directory */
+size_t ls(int8_t fd, struct dirent *buf, uint8_t all);
+
+/* find name through the directory entries */
+size_t find(int8_t fd, struct dirent *buf, const char *name);
+
+/* creates a new directory inside fd with the specified name */
+int8_t mkdir(int8_t fd, const char *name);
+
+/* creates a new file inside fd with the specified name */
+int8_t touch(int8_t fd, const char *name);
+
+/* creates a new symlink inside fd with the specified name */
+int8_t ln(int8_t fd, const char *name);
+
+/* change virtual seek position of the fd */
+int8_t seek(int8_t fd, fsize_t pos);
+
+/* reads a string from the fd until the terminator is reached */
+size_t readline(int8_t fd, char *buf, char term);
+
+/* writes a string into the fd */
+int8_t print(int8_t fd, const char *str);
+
+/* reads n bytes from the fd */
+size_t read(int8_t fd, void *buf, size_t n);
+
+/* writes n bytes into the fd */
+int8_t write(int8_t fd, const void *buf, size_t n);
+
+/* frees fd space */
+void close(int8_t fd);
+
+#endif  // __FD_H__
diff --git a/sw-old/z80/kernel/include/fs/fdop.h b/sw-old/z80/kernel/include/fs/fdop.h
new file mode 100644
index 0000000..d4b1b77
--- /dev/null
+++ b/sw-old/z80/kernel/include/fs/fdop.h
@@ -0,0 +1,140 @@
+#ifndef __FDOP_H__
+#define __FDOP_H__
+
+#include "types.h"
+
+#ifndef __DIRENT_H__
+struct dirent;
+#endif
+
+/* macro for direct binding */
+
+#define FD_BIND_AS_DIR(oper)    {       \
+                                    oper.ls = &as_ls;   \
+                                    oper.find = &as_find; \
+                                    oper.mkdir = &as_mkdir; \
+                                    oper.rmdir = &as_rmdir; \
+                                    oper.touch = &as_touch; \
+                                    oper.rm = &as_rm; \
+                                    oper.ln = &as_ln; \
+                                }
+
+#define FD_BIND_SS_DIR(oper)    {       \
+                                    oper.ls = &ss_ls;   \
+                                    oper.find = &ss_find; \
+                                    oper.mkdir = &ss_mkdir; \
+                                    oper.rmdir = &ss_rmdir; \
+                                    oper.touch = &ss_touch; \
+                                    oper.rm = &ss_rm; \
+                                    oper.ln = &ss_ln; \
+                                }
+
+#define FD_BIND_AS_FILE(opers, flags) {      \
+                                    if (flags & OPEN_READ)  \
+                                        opers.readline = as_readline;   \
+                                    if (flags & OPEN_APPEND)    \
+                                        opers.append = as_append;   \
+                                    else if (flags & OPEN_WRITE)    \
+                                        opers.print = as_print;     \
+                                    }
+
+#define FD_BIND_SS_FILE(opers, flags) {      \
+                                    if (flags & OPEN_READ)  \
+                                        opers.readline = ss_readline;   \
+                                    if (flags & OPEN_APPEND)    \
+                                        opers.append = ss_append;   \
+                                    else if (flags & OPEN_WRITE)    \
+                                        opers.print = ss_print;     \
+                                     }
+
+#define FD_BIND_AS_BINFILE(opers, flags) {     \
+                                        if (flags & OPEN_READ)  \
+                                            opers.read = as_read;   \
+                                        if (flags & OPEN_APPEND)    \
+                                            opers.bin_append = as_bin_append;   \
+                                        else if (flags & OPEN_WRITE)    \
+                                            opers.write = as_write;     \
+                                        }
+
+#define FD_BIND_SS_BINFILE(opers, flags) {     \
+                                        if (flags & OPEN_READ)  \
+                                            opers.read = ss_read;   \
+                                        if (flags & OPEN_APPEND)    \
+                                            opers.bin_append = ss_bin_append;   \
+                                        else if (flags & OPEN_WRITE)    \
+                                            opers.write = ss_write;     \
+                                        }
+
+/* Set of file descriptors operations */
+/* Determines if to use the serial interface or the address space */
+
+/* Address space section */
+
+/* File functions */
+
+size_t as_readline(inode_t inode, fsize_t seek, char *buf, char term);
+
+size_t as_print(inode_t inode, fsize_t seek, const char *str);
+
+size_t as_append(inode_t inode, fsize_t *seek_ptr, const char *str);
+
+
+size_t as_read(inode_t inode, fsize_t seek, void *buf, size_t n);
+
+size_t as_write(inode_t inode, fsize_t seek, const void *buf, size_t n);
+
+size_t as_bin_append(inode_t inode, fsize_t *seek_ptr, const void *buf, size_t
+n);
+
+/* Directory functions */
+
+size_t as_ls(inode_t inode, struct dirent *buf, uint8_t all);
+
+size_t as_find(inode_t inode, struct dirent *buf, const char *name);
+
+int8_t as_mkdir(inode_t inode, const char *name);
+
+int8_t as_rmdir(inode_t inode, const char *name);
+
+int8_t as_touch(inode_t inode, const char *name);
+
+int8_t as_rm(inode_t inode, const char *name);
+
+int8_t as_ln(inode_t inode, const char *path, const char *name);
+
+/* Serial Space section */
+/* Warning, it doesn't switch to the right driver */
+
+/* File functions */
+
+size_t ss_readline(inode_t inode, fsize_t seek, char *buf, char term);
+
+size_t ss_print(inode_t inode, fsize_t seek, const char *str);
+
+size_t ss_append(inode_t inode, fsize_t *seek_ptr, const char *str);
+
+
+size_t ss_read(inode_t inode, fsize_t seek, void *buf, size_t n);
+
+size_t ss_write(inode_t inode, fsize_t seek, const void *buf, size_t n);
+
+size_t ss_bin_append(inode_t inode, fsize_t *seek_ptr, const void *buf, size_t
+n);
+
+/* Directory functions */
+
+size_t ss_ls(inode_t inode, struct dirent *buf, uint8_t all);
+
+size_t ss_find(inode_t inode, struct dirent *buf, const char *name);
+
+int8_t ss_mkdir(inode_t inode, const char *name);
+
+int8_t ss_rmdir(inode_t inode, const char *name);
+
+int8_t ss_touch(inode_t inode, const char *name);
+
+int8_t ss_rm(inode_t inode, const char *name);
+
+int8_t ss_ln(inode_t, const char *path, const char *name);
+
+#endif // __FDOP_H__
diff --git a/sw-old/z80/kernel/include/fs/fs.h b/sw-old/z80/kernel/include/fs/fs.h
new file mode 100644
index 0000000..ad20adb
--- /dev/null
+++ b/sw-old/z80/kernel/include/fs/fs.h
@@ -0,0 +1,63 @@
+#ifndef __FS_H__
+#define __FS_H__
+
+#include "types.h"
+
+#define FS_OFFSET 0x1000
+
+#define FS_BLOCKS_SIZE 512
+#define FS_BLOCKS_N     8
+#define FS_BLOCKS_IND   6
+
+#define INODE_TYPE_FILE   0x0
+#define INODE_TYPE_DIR    0x1
+#define INODE_TYPE_SLINK    0x2
+#define INODE_TYPE_SPECIAL  0x3
+
+#define INODE_META_SIZE 8
+
+/* inode basic structure */
+struct fs_inode
+{
+    /* inode meta data */
+
+    uint        mode :3;  // chmod
+    uint        uid :3;   // chown
+    uint        type :2;  // file, dir, sym-link, special
+
+    time_t      ctime;          // creation time
+
+    uint24_t     size;              // inode size
+
+    /* data storage informations */
+    /* it doesn't allocate memory, virtual size FS_BLOCKS_N */ 
+    blk_t     blocks[];
+};
+
+#define FS_DEV_ROM      0x7f    /* 01111111 */
+#define FS_DEV_NULL     0x80    /* 10000000 */
+
+#define FS_ROM_SPACE    0x2000  // second rom 
+
+#define FS_INO_ROOT   0x0       // first inode
+
+#define FS_INODE_ROOT(inode)   {inode.dev = 0xff; inode.inode = 0x0}
+#define FS_INODE_NULL(inode)   {inode.dev = 0x80; inode.inode = 0x0}
+
+#define FS_USE_ROM(inode)   {inode.dev == 0x7f}
+
+/* get block seek in current device */
+devsize_t fs_block(blk_t block);
+
+/* get common inode seek in current device */
+/* c_inode must be set first */
+/* returns seek at the beginning of blocks field */
+devsize_t fs_inode(struct fs_inode *buf);
+
+/* common inode for syscalls */
+extern inode_t c_inode;
+
+/* parse a path, absolute or relative to c_inode */
+inode_t fs_parse_path(const char *path);
+
+#endif  // __FS_H__
diff --git a/sw-old/z80/kernel/include/fs/iter.h b/sw-old/z80/kernel/include/fs/iter.h
new file mode 100644
index 0000000..41f011d
--- /dev/null
+++ b/sw-old/z80/kernel/include/fs/iter.h
@@ -0,0 +1,17 @@
+#ifndef __ITER_H__
+#define __ITER_H__
+
+struct inode_iter
+{
+    devsize_t   dev_seek;       /* seek position in the volume */
+    devsize_t   blk_end;        /* end of the block */
+
+    int16_t     blk_index;      /* index of the block */
+
+    int8_t      blk_level;      /* recursion level, indirect blocks */
+    
+    fsize_t     fseek;          /* virtual seek in the file */
+    fsize_t     size;           /* file size */
+};
+
+#endif  // __ITER_H__
diff --git a/sw-old/z80/kernel/include/fs/users.h b/sw-old/z80/kernel/include/fs/users.h
new file mode 100644
index 0000000..83980e5
--- /dev/null
+++ b/sw-old/z80/kernel/include/fs/users.h
@@ -0,0 +1,21 @@
+#ifndef USERS_H
+#define USERS_H
+
+#include "types.h"
+
+#define USERS_MAX   8
+#define USER_ROOT   0 
+
+/* current user in use */
+extern struct fs_user c_user;
+
+struct fs_user
+{
+    char        name[32];
+    ino_t       home;
+    uint8_t     perm;       // TODO, permissions 
+};
+
+/* all users are in rom device */
+
+#endif
diff --git a/sw-old/z80/kernel/include/memory.h b/sw-old/z80/kernel/include/memory.h
new file mode 100644
index 0000000..67c4b88
--- /dev/null
+++ b/sw-old/z80/kernel/include/memory.h
@@ -0,0 +1,50 @@
+#ifndef __MEMORY_H__
+#define __MEMORY_H__
+
+#include "types.h"
+#include "devices.h"
+
+/* maximum number of pages on the system */
+#define PAGES_MAX_COUNT 32
+#define PAGE_SIZE     1000
+
+/* in our system there are only 16 pages since only 64KB can be addressed
+ * to optimize the memory management in ROM and RAM only pages from this set
+ * shall be used
+ */
+// ROM
+#define ADDR_PAGE_0  0x0000
+#define ADDR_PAGE_1  0x1000
+#define ADDR_PAGE_2  0x2000
+#define ADDR_PAGE_3  0x3000
+// IOSPACE
+#define ADDR_PAGE_4  0x4000
+#define ADDR_PAGE_5  0x5000
+#define ADDR_PAGE_6  0x6000
+#define ADDR_PAGE_7  0x7000
+// RAM
+#define ADDR_PAGE_8  0x8000
+#define ADDR_PAGE_9  0x9000
+#define ADDR_PAGE_10 0xA000
+#define ADDR_PAGE_11 0xB000
+#define ADDR_PAGE_12 0xC000
+#define ADDR_PAGE_13 0xD000
+#define ADDR_PAGE_14 0xE000
+#define ADDR_PAGE_15 0xF000
+
+#define ADDR_PAGE_FIRST  ADDR_PAGE_8
+#define ADDR_PAGE_LAST   ADDR_PAGE_15
+
+struct page
+{
+	pid_t pid;       // process owner of the page (0 if free)
+    uint16_t addr;   // physical address
+};
+
+int mmu_write_table(void);
+
+int page_new(void);
+int page_map(int page, int pid, uint16_t addr);
+int page_unmap(int page);
+
+#endif // __MEMORY_H__
diff --git a/sw-old/z80/kernel/include/process.h b/sw-old/z80/kernel/include/process.h
new file mode 100644
index 0000000..3b0c843
--- /dev/null
+++ b/sw-old/z80/kernel/include/process.h
@@ -0,0 +1,43 @@
+#ifndef __PROCESS_H__
+#define __PROCESS_H__
+
+#include "types.h"
+#include "memory.h"
+
+ /* maximum number of processes (i.e. pages in ram)
+  * since each program can use only one page in ram
+  */
+#define PROC_COUNT 2 
+
+/* the pid is defined with a single byte (pid_t is uint8_t), because of that 
+ * there cannot be more than 255 processes open at the same time. this is a
+ * limitation but for our purposes is more than enough
+ */
+#define PID_COUNT_MAX 255
+
+struct executable
+{
+    void *text;
+    size_t text_size;
+    void *bss;
+    size_t bss_size;
+};
+
+struct process
+{
+    uint blocked :1;      // process is waiting for hardware or locked
+    uint running :1;      // pid is used
+    uint pages;           // number of pages used by the process
+    struct page page[4];  // pages used by the process
+};
+
+pid_t newpid(void);
+
+int fork(void);
+int exec(char *path, char *args);
+int spawn(char *path, char *args);
+
+pid_t getpid(void);
+int kill(pid_t pid);
+
+#endif // __PROCESS_H__
diff --git a/sw-old/z80/kernel/include/sio.h b/sw-old/z80/kernel/include/sio.h
new file mode 100644
index 0000000..276b99c
--- /dev/null
+++ b/sw-old/z80/kernel/include/sio.h
@@ -0,0 +1,43 @@
+#ifndef __SIO_H__
+#define __SIO_H__
+
+#include "types.h"
+
+#define SIO_PORT_0 0x0
+#define SIO_PORT_1 0x1
+#define SIO_PORT_2 0x2
+#define SIO_PORT_3 0x3
+#define SIO_PORT_4 0x4
+#define SIO_PORT_5 0x5
+#define SIO_PORT_6 0x6
+#define SIO_PORT_7 0x7
+
+/* current port in use */
+extern uint8_t      sio_port;
+
+/* current seek in the device */
+extern devsize_t    sio_seek;
+
+struct dev_buffer
+{
+   // TODO, bytes needed to the device buffer interface
+};
+
+/* points to the buffers mapped in the I/O space */
+/* to be defined precisely in assembly */
+extern volatile struct dev_buffer sio_buffers[8];
+
+/* initialize serial interface */
+void sio_init();
+
+/* syscall: read one byte from the current device */
+uint8_t sio_recv();
+/* syscall: write one byte into the current device */
+void sio_send(uint8_t value);
+
+/* read n bytes from the current port */
+size_t sio_read(void *buffer, size_t n);
+/* write n bytes into the current port */
+int8_t sio_write(const void *buffer, size_t n);
+
+#endif  // __SIO_H__
diff --git a/sw-old/z80/kernel/include/stat.h b/sw-old/z80/kernel/include/stat.h
new file mode 100644
index 0000000..44c0f63
--- /dev/null
+++ b/sw-old/z80/kernel/include/stat.h
@@ -0,0 +1,24 @@
+#ifndef __STAT_H__
+#define __STAT_H__
+
+#include "types.h"
+
+struct stat
+{
+    inode_t     inode;      /* inode reference */
+
+    uint        mode :3;    /* mode */
+    uint        uid :3;     /* owner id */
+    uint        type :2;    /* file, dir or link */
+
+    devsize_t   size;       /* file size */
+
+    size_t      blk_size;   /* single block size */
+    size_t      blk_used;   /* blocks used by the file */
+
+    time_t      ctime;      /* creation time */
+}
+
+struct stat * stat(const char *path, struct stat *buffer);
+
+#endif  // __STAT_H__
diff --git a/sw-old/z80/kernel/include/types.h b/sw-old/z80/kernel/include/types.h
new file mode 100644
index 0000000..c6e620b
--- /dev/null
+++ b/sw-old/z80/kernel/include/types.h
@@ -0,0 +1,62 @@
+#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-old/z80/kernel/kernel.c b/sw-old/z80/kernel/kernel.c
new file mode 100644
index 0000000..3d5aeb6
--- /dev/null
+++ b/sw-old/z80/kernel/kernel.c
@@ -0,0 +1,7 @@
+#include "types.h"
+#include "usart.h"
+
+void kmain(void)
+{
+    usart_init(USART_BAUDRATE_9600, USART_PARITY_EVEN, USART_STOP_BITS_1);
+}
diff --git a/sw-old/z80/kernel/makefile b/sw-old/z80/kernel/makefile
new file mode 100644
index 0000000..be8eed4
--- /dev/null
+++ b/sw-old/z80/kernel/makefile
@@ -0,0 +1,53 @@
+####
+# source code settings
+#
+OSNAME := helvetiOS
+ 
+CSOURCES 	:=  $(wildcard *.c) \
+				$(wildcard drivers/*.c)
+
+OBJECTS 	:= $(patsubst %.c,build/%.rel,$(CSOURCES))
+HEXFILE		:= build/$(OSNAME).hex
+BINARY  	:= build/$(OSNAME).bin
+
+### 
+# compiler settings
+
+CC 		:= sdcc
+
+CFLAGS	:= -mz80 \
+			-I include \
+			-I include/drivers \
+			-I libc/include \
+			--opt-code-size \
+			-DDEBUG
+
+LDFLAGS := -mz80 --no-std-crt0 build/crt0.rel \
+			--std-c89 -pedantic \
+			--code-loc 0x0800 --data-loc 0x8000
+
+.PHONY: dirs dis clean
+all: $(BINARY)
+
+# build binary
+$(BINARY): $(OBJECTS) dirs
+	$(CC) $(LDFLAGS) $(OBJECTS) -o $(HEXFILE)
+	makebin -s 16384 $(HEXFILE) $(BINARY)
+
+$(OBJECTS): build/%.rel : %.c $(CSOURCES) dirs build/crt0.rel
+	@printf "\n"
+	$(CC) $(CFLAGS) -c $< -o $@
+
+build/crt0.rel: crt0.s
+	sdasz80 -o $<
+	@mv crt0.rel build
+
+dirs:
+	mkdir -p build build/kernel build/libc build/kernel/drivers
+
+dis: $(BINARY)
+	dz80 -b -n $<
+
+clean:
+	- rm -rd build/*
+	- rm crt0.rel
diff --git a/sw-old/z80/kernel/memory.c b/sw-old/z80/kernel/memory.c
new file mode 100644
index 0000000..1b2cc76
--- /dev/null
+++ b/sw-old/z80/kernel/memory.c
@@ -0,0 +1,94 @@
+#include "memory.h"
+
+static struct page pages_table[PAGES_MAX_COUNT];
+
+int mmu_write_table(void)
+{
+    int i;
+
+    for (i = 0; i < PAGES_MAX_COUNT; i++) {
+        if (pages_table[i].pid != 0) {
+            // write to mmu table
+        }
+    }
+
+    return 0;
+}
+
+int page_new(void)
+{
+    int i, used;
+    uint16_t addr;
+
+    for (addr = ADDR_PAGE_FIRST; addr < ADDR_PAGE_LAST; addr += PAGE_SIZE) {
+        used = 0;
+
+        for (i = 0; i < PAGES_MAX_COUNT; i++) {
+            if (pages_table[i].addr == addr) {
+                used = 1;
+                break;
+            }
+        }
+
+        if (!used)
+            return i;
+    }
+
+    return -1;
+}
+
+int page_map(int page, int pid, uint16_t addr)
+{
+    if (page >= PAGES_MAX_COUNT)
+        return -1;
+
+    if (pages_table[page].pid != 0)
+        return -2;
+
+    pages_table[page].addr = addr;
+    pages_table[page].pid = pid;
+
+    return 0;
+}
+
+int page_unmap(int page)
+{
+    if (page >= PAGES_MAX_COUNT)
+        return -1;
+
+    if (pages_table[page].pid == 0)
+        return -2;
+
+    pages_table[page].pid = 0;
+    pages_table[page].addr = 0;
+    return 0;
+}
+
+/* k_malloc manager */
+/*
+struct k_buf_entry k_buf_table[K_BUF_MAX_COUNT];
+
+struct k_buf k_buffers[K_BUF_MAX_COUNT];
+
+void * k_malloc()
+{
+    for (uint8_t i = 0; i < K_BUF_TABLE_COUNT; i++)
+    {
+        for (uint8_t bit = 0x80, j = 0; j < 8; bit >>= 1, j++)
+        {
+            if (bit & k_buf_table[i])
+            {
+                k_buf_table[i] |= bit;
+                return &k_buffers[8 * i + j];
+            }
+        }
+    }
+}
+
+void k_free(void * ptr)
+{
+    uint8_t index = (ptr - &k_buffers[0]) / K_BUF_SIZE;
+
+    if (index < K_BUF_MAX_COUNT)
+        k_buf_table[index / 8] ^= 0x80 >> index % 8;
+}*/
diff --git a/sw-old/z80/kernel/process.c b/sw-old/z80/kernel/process.c
new file mode 100644
index 0000000..7d8db89
--- /dev/null
+++ b/sw-old/z80/kernel/process.c
@@ -0,0 +1,58 @@
+#include "process.h"
+
+static struct process proc_table[PID_COUNT_MAX];
+static struct process *current_proc;
+
+pid_t newpid(void)
+{
+    int i;
+    static pid_t last_pid = 0;
+
+    for (i = 0; i < PID_COUNT_MAX; i++, last_pid++) {
+        if (last_pid == PID_COUNT_MAX) {
+            last_pid = 0;
+            continue;            
+        }
+
+        if (!proc_table[last_pid].running)
+            break;
+    }
+
+    if (i >= PID_COUNT_MAX)
+        return 0;
+
+    return last_pid;
+}
+
+int fork(void)
+{
+    int i, p;
+    pid_t child_pid = newpid();
+
+    if (child_pid == 0)
+        return -1;
+
+
+    for (i = 0; i < current_proc->pages; i++) {
+        p = page_new();
+
+        if (p == -1) {
+            return -2;
+        }
+
+        // TODO: use memcpy()
+        // SDCC does not allow assignemnts of structs
+
+        // proc_table[child_pid].page[i] = p;
+    }
+}
+
+int exec(char *path, char *args)
+{
+    
+}
+
+int spawn(char *path, char *args)
+{
+    
+}
diff --git a/sw-old/z80/libc/include/stdint.h b/sw-old/z80/libc/include/stdint.h
new file mode 100644
index 0000000..5e8caf3
--- /dev/null
+++ b/sw-old/z80/libc/include/stdint.h
@@ -0,0 +1,13 @@
+#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;
+typedef long int                    int32_t;
+typedef unsigned long int           uint32_t;
+
+#endif // __STDINT_H__
\ No newline at end of file
diff --git a/sw-old/z80/libc/include/stdio.h b/sw-old/z80/libc/include/stdio.h
new file mode 100644
index 0000000..b31cdfd
--- /dev/null
+++ b/sw-old/z80/libc/include/stdio.h
@@ -0,0 +1,11 @@
+#ifndef __STDIO_H__
+#define __STDIO_H__
+
+#include "types.h"
+
+extern uint8_t *stdout, stderr;
+
+void putc(char ch, uint8_t *buffer);
+int printf(const char *fmt, ...);
+
+#endif 
diff --git a/sw-old/z80/libc/include/stdlib.h b/sw-old/z80/libc/include/stdlib.h
new file mode 100644
index 0000000..c69f573
--- /dev/null
+++ b/sw-old/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-old/z80/libc/include/string.h b/sw-old/z80/libc/include/string.h
new file mode 100644
index 0000000..9c002e3
--- /dev/null
+++ b/sw-old/z80/libc/include/string.h
@@ -0,0 +1,12 @@
+#ifndef __STRING_H__
+#define __STRING_H__
+
+#include "types.h"
+
+void * memset(void *dest, const int8_t src, size_t n);
+
+void *memcpy(void *dest, const void *src, size_t n);
+
+int8_t memcmp(const void *s1, const void *s2, size_t n);
+
+#endif
diff --git a/sw-old/z80/libc/include/sysio.h b/sw-old/z80/libc/include/sysio.h
new file mode 100644
index 0000000..5d1f5ae
--- /dev/null
+++ b/sw-old/z80/libc/include/sysio.h
@@ -0,0 +1,55 @@
+#ifndef __SYSIO_H__
+#define __SYSIO_H__
+
+#include "types.h"
+
+/*
+* 	Memory management
+*/
+
+void * malloc(uint16_t size);
+uint16_t malloc_size(void * address);
+void free(void * address);
+
+/*
+*	File management
+*/
+
+#define F_WRITE "w"
+#define F_READ "r"
+#define F_BIN_WRITE "wb"
+#define F_BIN_READ "rb"
+
+#define F_READ_CODE 0x0
+#define F_WRITE_CODE 0x1
+#define F_BIN_READ_CODE 0x2
+#define F_BIN_WRITE_CODE 0x3
+
+#define F_PERM_READ 0x0
+#define F_PERM_WRITE 0x1
+#define F_PERM_RW 0x2
+
+struct file {
+
+	const char * path;
+	unsigned int mode:4;
+	unsigned int permission:4;
+};
+
+#define FILE struct file
+
+FILE * fopen(const char * path, const char * mode);
+uint8_t fclose(FILE * file);
+
+// TODO: other functions
+
+/*
+*	Processes management
+*/
+
+#define PID uint16_t
+
+void exit();	// exit this program
+void interrupt(PID)
+
+#endif
\ No newline at end of file
diff --git a/sw-old/z80/libc/include/types.h b/sw-old/z80/libc/include/types.h
new file mode 100644
index 0000000..a083bfe
--- /dev/null
+++ b/sw-old/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-old/z80/libc/stdio.c b/sw-old/z80/libc/stdio.c
new file mode 100644
index 0000000..c2548d6
--- /dev/null
+++ b/sw-old/z80/libc/stdio.c
@@ -0,0 +1,12 @@
+#include "stdio.h"
+
+void putc(char ch, uint8_t *buffer)
+{
+    *buffer = ch;
+    *(++buffer) = '\0';
+}
+
+
+int printf(const char *fmt, ...)
+{
+}
diff --git a/sw-old/z80/libc/string.c b/sw-old/z80/libc/string.c
new file mode 100644
index 0000000..57b3a7f
--- /dev/null
+++ b/sw-old/z80/libc/string.c
@@ -0,0 +1,37 @@
+#include "string.h"
+
+void *memset(void *dest, const int8_t src, size_t n) {
+
+    char *dp = (char *) dest;
+
+    while (n--)
+        *(dp++) = src;
+
+    return dest;
+}
+
+void *memcpy(void *dest, void *src, size_t n)
+{
+    char *dp = dest;
+    char *sp = src;
+
+    while (n--) {
+        *dp++ = *sp++;
+    }
+
+    return dest;
+}
+
+int8_t memcmp(void *s1, void *s2, size_t n)
+{
+    char *u1 = (char *) s1;
+    char *u2 = (char *) s2;
+
+    for ( ; n--; u1++, u2++) {
+
+        if (*u1 != *u2)
+            return u1 - u2;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/sw-old/z80/tests/asm/main.s b/sw-old/z80/tests/asm/main.s
new file mode 100644
index 0000000..8cf4df0
--- /dev/null
+++ b/sw-old/z80/tests/asm/main.s
@@ -0,0 +1,40 @@
+    .module crt0
+    .area   _HEADER (ABS)
+
+;; Reset vectors
+    .org    0
+    jp  init
+
+    .org    0x38 ; the instruction 0xff (not written) resets to this location
+    jp init
+
+;; main code
+    .org    0x100
+    .globl  _main
+
+init:
+    ;; Set stack pointer directly above top of memory.
+    ld  sp,#0xffff
+
+    ;; Start of the program
+    call    _main
+    jp      _exit
+
+_exit:
+    halt
+    ; jp  _exit
+
+;; Ordering of segments for the linker.
+    .area   _HOME
+    .area   _CODE
+_main:
+    ret
+    .area   _INITIALIZER
+    .area   _GSINIT
+    .area   _GSFINAL
+
+    .area   _DATA
+    .area   _INITIALIZED
+    .area   _BSEG
+    .area   _BSS
+    .area   _HEAP
diff --git a/sw-old/z80/tests/asm/makefile b/sw-old/z80/tests/asm/makefile
new file mode 100644
index 0000000..413b0fe
--- /dev/null
+++ b/sw-old/z80/tests/asm/makefile
@@ -0,0 +1,47 @@
+####
+# source code settings
+#
+OSNAME := ram_test
+ 
+CSOURCES 	:=  $(wildcard *.s)
+
+OBJECTS 	:= $(patsubst %.s,build/%.rel,$(SOURCES))
+HEXFILE		:= build/$(OSNAME).hex
+BINARY  	:= build/$(OSNAME).bin
+
+### 
+# compiler settings
+#
+ASM		:= sdasz80
+LD		:= sdldz80
+
+FLAGS	:= 
+LDFLAGS :=
+
+.PHONY: flash dirs dis clean
+all: $(BINARY)
+
+flash: $(BINARY)
+	minipro -p M28C64 -w $< 
+
+# build binary
+$(BINARY): $(OBJECTS) dirs
+	$(LD) $(LDFLAGS) $(OBJECTS) -o $(HEXFILE)
+	makebin -s 8192 -yo 1 $(HEXFILE) $(BINARY)
+
+$(OBJECTS): build/%.rel : %.s $(SOURCES) dirs
+	@printf "\n"
+	$(ASM) $(FLAGS) $< -o
+
+build/crt0.rel: crt0.s
+	sdasz80 -o $<
+	@mv crt0.rel build/
+
+dirs:
+	mkdir -p build
+
+dis: $(BINARY)
+	r2 -a z80 $< -c 'pd 0x10; s 0x100; pd 10; s 0x200; pd 10'
+
+clean:
+	- rm -rd build
diff --git a/sw-old/z80/tests/pio/crt0.s b/sw-old/z80/tests/pio/crt0.s
new file mode 100644
index 0000000..c900065
--- /dev/null
+++ b/sw-old/z80/tests/pio/crt0.s
@@ -0,0 +1,38 @@
+    .module crt0
+    .area   _HEADER (ABS)
+
+;; Reset vectors
+    .org    0
+    jp  init
+
+    .org    0x38 ; the instruction 0xff (not written) resets to this location
+    jp init
+
+;; main code
+    .org    0x100
+    .globl  _main
+
+init:
+    ;; Set stack pointer directly above top of memory.
+    ld  sp,#0xffff
+
+    ;; Start of the program
+    call    _main
+    jp      _exit
+
+_exit:
+    halt
+    ; jp  _exit
+
+;; Ordering of segments for the linker.
+    .area   _HOME
+    .area   _CODE
+    .area   _INITIALIZER
+    .area   _GSINIT
+    .area   _GSFINAL
+
+    .area   _DATA
+    .area   _INITIALIZED
+    .area   _BSEG
+    .area   _BSS
+    .area   _HEAP
diff --git a/sw-old/z80/tests/pio/main.c b/sw-old/z80/tests/pio/main.c
new file mode 100644
index 0000000..7ac64bc
--- /dev/null
+++ b/sw-old/z80/tests/pio/main.c
@@ -0,0 +1,50 @@
+// #include "pio.h"
+
+#include <stdint.h>
+
+#define PIO_A_DATA  0x10
+#define PIO_B_DATA  0x11
+#define PIO_A_CMD   0x12
+#define PIO_B_CMD   0x13
+
+void main(void)
+{
+    __asm
+    ;; output variable
+    ld h, #0x00
+
+    ;; set bit mode
+    ld c, #PIO_B_CMD
+
+    ld a, #0xCF
+    out (c), a
+
+    ;; set all pins to output
+    ld a, #0x00
+    out (c), a
+
+    ;; disable interrupts
+    ld a, #0x0C
+    out (c), a
+
+    ;; load data addr
+    ld c, #PIO_B_DATA
+loop:
+    out (c), h
+    ld a, h
+
+    cpl
+    ld h, a
+    jr loop
+    __endasm; 
+
+    // uint8_t i = 0;
+
+    // pio_set_mode(PIO_A, PIO_MODE_BIT_IO, 0x00);
+    // pio_set_interrupts(PIO_A, PIO_INT_DISABLE);
+
+    // while (1) {
+    //     pio_write(PIO_A, i);
+    //     i = ~i;
+    // }
+}
\ No newline at end of file
diff --git a/sw-old/z80/tests/pio/makefile b/sw-old/z80/tests/pio/makefile
new file mode 100644
index 0000000..1213902
--- /dev/null
+++ b/sw-old/z80/tests/pio/makefile
@@ -0,0 +1,72 @@
+####
+# source code settings
+#
+OSNAME := pio_test
+ 
+CSOURCES 	:=  $(wildcard *.c)
+LIBS 		:= ../../arch/build/arch.a \
+			   ../../drivers/build/drivers.a
+
+OBJECTS 	:= $(patsubst %.c,build/%.rel,$(CSOURCES))
+HEXFILE		:= build/$(OSNAME).hex
+BINARY  	:= build/$(OSNAME).bin
+
+### 
+# compiler settings
+#
+CC 		:= sdcc
+
+CFLAGS	:= -mz80 \
+			--no-std-crt0 build/crt0.rel \
+			--allow-unsafe-read \
+			-I . \
+			-I ../../arch/include \
+			-I ../../drivers/include \
+			-DDEBUG
+
+LDFLAGS := -mz80 \
+			--no-std-crt0 build/crt0.rel \
+			-L ../../drivers/build \
+			-l drivers.a \
+			-pedantic \
+			--code-loc 0x0200
+			# --data-loc 0x2000
+
+.PHONY: flash dirs dis clean
+all: $(BINARY)
+
+flash: $(BINARY)
+	minipro -p M28C64 -w $< 
+
+# build binary
+$(BINARY): $(OBJECTS) dirs
+	$(CC) $(LDFLAGS) $(OBJECTS) -o $(HEXFILE)
+	makebin -s 8192 -yo 1 $(HEXFILE) $(BINARY)
+
+$(OBJECTS): build/%.rel : %.c $(CSOURCES) dirs build/crt0.rel $(LIBS)
+	@printf "\n"
+	$(CC) $(CFLAGS) -c $< -o $@
+
+$(LIBS): %.a:
+	@printf "\n"
+	make -C $(shell printf $@ | sed 's:build.*.::')
+
+build/crt0.rel: crt0.s
+	sdasz80 -o $<
+	@mv crt0.rel build/
+
+dirs:
+	mkdir -p build
+
+dis: $(BINARY)
+	dz80 -b -n -t $(BINARY)
+	r2 -a z80 $< \
+	-c 'afn main 0x200; \
+		pd 0x10; \
+		s 0x100; \
+		pd 10; \
+		s 0x200; \
+		pd 0x95' | tee build/dis.txt
+
+clean:
+	- rm -rd build
diff --git a/sw-old/z80/tests/ram/crt0.s b/sw-old/z80/tests/ram/crt0.s
new file mode 100644
index 0000000..b0caa8c
--- /dev/null
+++ b/sw-old/z80/tests/ram/crt0.s
@@ -0,0 +1,40 @@
+	.module crt0
+	.area	_HEADER (ABS)
+
+;; Reset vectors
+	.org 	0
+	jp	init
+
+	.org	0x38 ; the instruction 0xff (not written) resets to this location
+    jp init
+
+;; main code
+	.org	0x100
+    .globl  _main
+
+init:
+	;; Set stack pointer directly above top of memory.
+	ld	sp,#0xffff
+
+	;; Start of the program
+	call	_main
+	jp	    _exit
+
+_exit:
+    halt
+    jp  _exit
+
+;; Ordering of segments for the linker.
+	.area	_HOME
+	.area	_CODE
+	.area	_INITIALIZER
+	.area   _GSINIT
+	.area   _GSFINAL
+
+	.area	_DATA
+	.area	_INITIALIZED
+	.area	_BSEG
+	.area   _BSS
+	.area   _HEAP
+
+	.area   _CODE
\ No newline at end of file
diff --git a/sw-old/z80/tests/ram/main.c b/sw-old/z80/tests/ram/main.c
new file mode 100644
index 0000000..581072b
--- /dev/null
+++ b/sw-old/z80/tests/ram/main.c
@@ -0,0 +1,13 @@
+
+void main(void)
+{
+    unsigned char j;
+    unsigned char *mem;
+    
+    j = 0;
+    mem = (unsigned char *) 0x8200; // somwhere in ram
+
+    while (1) {
+        *mem = j++;
+    }
+}
diff --git a/sw-old/z80/tests/ram/makefile b/sw-old/z80/tests/ram/makefile
new file mode 100644
index 0000000..f8eb9fc
--- /dev/null
+++ b/sw-old/z80/tests/ram/makefile
@@ -0,0 +1,54 @@
+####
+# source code settings
+#
+OSNAME := ram_test
+ 
+CSOURCES 	:=  $(wildcard *.c)
+
+OBJECTS 	:= $(patsubst %.c,build/%.rel,$(CSOURCES))
+HEXFILE		:= build/$(OSNAME).hex
+BINARY  	:= build/$(OSNAME).bin
+
+### 
+# compiler settings
+#
+CC 		:= sdcc
+
+CFLAGS	:= -mz80 \
+			-I . \
+			-DDEBUG
+
+LDFLAGS := -mz80 \
+			--no-std-crt0 build/crt0.rel \
+			-pedantic 
+
+			# --code-loc 0x0120 \
+			# --data-loc 0x2000
+
+.PHONY: flash dirs dis clean
+all: $(BINARY)
+
+flash: $(BINARY)
+	minipro -p M28C64 -w $< 
+
+# build binary
+$(BINARY): $(OBJECTS) dirs
+	$(CC) $(LDFLAGS) $(OBJECTS) -o $(HEXFILE)
+	makebin -s 8192 -yo 1 $(HEXFILE) $(BINARY)
+
+$(OBJECTS): build/%.rel : %.c $(CSOURCES) dirs build/crt0.rel
+	@printf "\n"
+	$(CC) $(CFLAGS) -c $< -o $@
+
+build/crt0.rel: crt0.s
+	sdasz80 -o $<
+	@mv crt0.rel build/
+
+dirs:
+	mkdir -p build
+
+dis: $(BINARY)
+	r2 -a z80 $< -c 'pd 0x10; s 0x100; pd 10; s 0x200; pd 10'
+
+clean:
+	- rm -rd build
diff --git a/sw-old/z80/tests/usart/crt0.s b/sw-old/z80/tests/usart/crt0.s
new file mode 100644
index 0000000..c900065
--- /dev/null
+++ b/sw-old/z80/tests/usart/crt0.s
@@ -0,0 +1,38 @@
+    .module crt0
+    .area   _HEADER (ABS)
+
+;; Reset vectors
+    .org    0
+    jp  init
+
+    .org    0x38 ; the instruction 0xff (not written) resets to this location
+    jp init
+
+;; main code
+    .org    0x100
+    .globl  _main
+
+init:
+    ;; Set stack pointer directly above top of memory.
+    ld  sp,#0xffff
+
+    ;; Start of the program
+    call    _main
+    jp      _exit
+
+_exit:
+    halt
+    ; jp  _exit
+
+;; Ordering of segments for the linker.
+    .area   _HOME
+    .area   _CODE
+    .area   _INITIALIZER
+    .area   _GSINIT
+    .area   _GSFINAL
+
+    .area   _DATA
+    .area   _INITIALIZED
+    .area   _BSEG
+    .area   _BSS
+    .area   _HEAP
diff --git a/sw-old/z80/tests/usart/main.c b/sw-old/z80/tests/usart/main.c
new file mode 100644
index 0000000..a905df2
--- /dev/null
+++ b/sw-old/z80/tests/usart/main.c
@@ -0,0 +1,11 @@
+#include "usart.h"
+#include <stdint.h>
+
+void main(void)
+{
+    usart_init(USART_BAUDRATE_1200, USART_PARITY_NONE, USART_STOP_BITS_1);
+
+    while (1) {
+        usart_write("Hello World!\n", 13);
+    }
+}
diff --git a/sw-old/z80/tests/usart/makefile b/sw-old/z80/tests/usart/makefile
new file mode 100644
index 0000000..8aaf6b1
--- /dev/null
+++ b/sw-old/z80/tests/usart/makefile
@@ -0,0 +1,72 @@
+####
+# source code settings
+#
+OSNAME := usart_test
+ 
+CSOURCES 	:=  $(wildcard *.c)
+LIBS 		:= ../../arch/build/arch.a \
+			   ../../drivers/build/drivers.a
+
+OBJECTS 	:= $(patsubst %.c,build/%.rel,$(CSOURCES))
+HEXFILE		:= build/$(OSNAME).hex
+BINARY  	:= build/$(OSNAME).bin
+
+### 
+# compiler settings
+#
+CC 		:= sdcc
+
+CFLAGS	:= -mz80 \
+			--no-std-crt0 build/crt0.rel \
+			--allow-unsafe-read \
+			-I . \
+			-I ../../arch/include \
+			-I ../../drivers/include \
+			-DDEBUG
+
+LDFLAGS := -mz80 \
+			--no-std-crt0 build/crt0.rel \
+			-L ../../drivers/build \
+			-l drivers.a \
+			-pedantic \
+			--code-loc 0x0200
+			# --data-loc 0x2000
+
+.PHONY: flash dirs dis clean
+all: $(BINARY)
+
+flash: $(BINARY)
+	minipro -p M28C64 -w $< 
+
+# build binary
+$(BINARY): $(OBJECTS) dirs
+	$(CC) $(LDFLAGS) $(OBJECTS) -o $(HEXFILE)
+	makebin -s 8192 -yo 1 $(HEXFILE) $(BINARY)
+
+$(OBJECTS): build/%.rel : %.c $(CSOURCES) dirs build/crt0.rel $(LIBS)
+	@printf "\n"
+	$(CC) $(CFLAGS) -c $< -o $@
+
+$(LIBS): %.a:
+	@printf "\n"
+	make -C $(shell printf $@ | sed 's:build.*.::')
+
+build/crt0.rel: crt0.s
+	sdasz80 -o $<
+	@mv crt0.rel build/
+
+dirs:
+	mkdir -p build
+
+dis: $(BINARY)
+	dz80 -b -n -t $(BINARY)
+	r2 -a z80 $< \
+	-c 'afn main 0x200; \
+		pd 0x10; \
+		s 0x100; \
+		pd 10; \
+		s 0x200; \
+		pd 0x95'
+
+clean:
+	- rm -rd build