Merge branch 'master' of github.com:NaoPross/z80uPC into atlas

Serial updates from NaoPross

13 files changed, 477 insertions, 8 deletions

diff --git a/sw/z80/coding_rules.txt b/sw/z80/coding_rules.txt
new file mode 100644
index 0000000..e5c11f0
--- /dev/null
+++ b/sw/z80/coding_rules.txt
@@ -0,0 +1,120 @@
+CODING STYLE FOR THIS PROJECT
+=============================
+
+In order to have a consistent codebase, there are the following rules on
+writing code in C (and assembly). For the most part they are similar to the
+Linux kernel coding rules by Torvalds.
+
+PROGRAM LOGIC
+-------------
+I expect a certain level of common sense from people so I won't mention the
+super-basic stuff. But I would like to point out a few thing I WON'T accept
+(unless there is a valid reason and an explanation of why).  First, I believe
+that code has to be aesthetically pleasing to watch and with a clear logic
+flow so:
+
+    - Avoid deeply nested code and recursive black magic
+
+    - No special cases: generally the code of a function should behave the
+      same with any argument. Avoid horrible exceptions for magic values
+
+    - No extreme modularization: do not write code that is extremely
+      encapsulated with dozens of helper functions to control every signal
+      that runs through the damn motherboard
+
+EDITOR (SPACES > TABS)
+----------------------
+You can use your favourite editor but spaces are better than tabs, no
+discussion. For this project every source file must have an indent of 4
+spaces. Since 80 characters is the standard terminal width, the code has to be
+hard wrapped at 80, 78 or 72 characters. Also there shouldn't be any markup on
+the source code for your editor, not even in the comments; just the code.
+
+    - use spaces, 1 indent - 4 spaces
+    - hard wrap at 80 / 78 / 72 characters
+    - no markup for folds or any other editor specific feature
+    
+
+C CODE INDENT AND BRACES
+------------------------
+I personally prefer the K&R coding style because it was used in 'The C
+Programming Language' book from Dennis Ritchie which is the 'standard' for
+learning C. But I also like Linus' kernel coding rules, so sometimes I might
+use some of his rules. Anyway, you can look them up if you want to or just
+look at the following example that sums most of the important stuff.
+
+    - K&R braces and function prototypes
+    - snake_case for variables and function names
+    - pointer asterisk in front of the variable ( ex: int *p; )
+
+Here's a short example that uses most of the stuff:
+
+    #include <stdio.h>
+    #include <stdlib.h>
+    
+    #define MY_DEVICE_MEMORY_ADDR   0x5020
+
+    #define MY_DEVICE_FLAG_RDY      1
+    #define MY_DEVICE_FLAG_ERR      2
+
+    // same for unions
+    struct my_device
+    {
+        volatile uint8_t buffer;
+        volatile uint8_t flags;
+    } *_my_dev = (struct my_device *) MY_DEVICE_MEMORY_ADDR;
+
+    
+    int my_device_write(uint8_t *data, size_t size);
+
+    /* This is the main function
+     * and this is a multiline comment to explain something if needed
+     */
+    int main(int argc, char *argv[])
+    {
+        int i;
+        int j = 0;
+        uint8_t data[2] = { 0xFF, 0xAB };
+        const char *string = "My magic string";
+
+        while (j < 100) {
+            j++;
+        }
+
+        printf("%s\n", string);
+
+        if (some_condition) {
+            // inline comment
+        } else {
+            my_device_write(data, 2);
+        }
+
+        switch (i) {
+        case 0:
+            some_function();
+            break;
+
+        case 1:
+            // ...
+            break;
+
+        default:
+            // ...
+        }
+    }
+
+    int my_device_write(uint8_t *data, size_t size) 
+    {
+        int i;
+
+        for (i = 0; i < size; i++) {
+            _my_dev.buffer = data;
+            while (!(_my_dev.flags & (1<<MY_DEVICE_FLAG_RDY)));
+
+            if (_my_dev.flags &  (1<<MY_DEVICE_FLAG_ERR)) {
+                return -1;
+            }
+        }
+
+        return i;
+    }
diff --git a/sw/z80/crt0.s b/sw/z80/crt0.s
index 7701ca6..00c7da1 100644
--- a/sw/z80/crt0.s
+++ b/sw/z80/crt0.s
@@ -27,7 +27,7 @@
 ;--------------------------------------------------------------------------
 
 	.module crt0
-	.globl	_main
+	.globl	_kmain
 
 	.area	_HEADER (ABS)
 	;; Reset vector
@@ -56,7 +56,7 @@ init:
 
 	;; Initialise global variables
 	call	gsinit
-	call	_main
+	call	_kmain
 	jp	    _exit
 
 	;; Ordering of segments for the linker.
diff --git a/sw/z80/kernel/include/devices.h b/sw/z80/kernel/include/devices.h
new file mode 100644
index 0000000..e8c183f
--- /dev/null
+++ b/sw/z80/kernel/include/devices.h
@@ -0,0 +1,13 @@
+#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_RAM        0x8000
+
+#endif
diff --git a/sw/z80/kernel/include/pio.h b/sw/z80/kernel/include/pio.h
new file mode 100644
index 0000000..5d289ca
--- /dev/null
+++ b/sw/z80/kernel/include/pio.h
@@ -0,0 +1,35 @@
+#ifndef __PIO_H__
+#define __PIO_H__
+
+#include "devices.h"
+#include "types.h"
+
+#define PIO_A       0
+#define PIO_B       1
+
+#define PIO_MODE_0  0
+#define PIO_MODE_1  1
+#define PIO_MODE_2  2
+#define PIO_MODE_3  3
+
+#define PIO_INT_ACTIVE_HIGH     (1<<5)
+#define PIO_INT_AND_MODE        (1<<6)
+#define PIO_INT_ENABLE          (1<<7)
+
+
+void _pio_data(int port, uint8_t data);
+void _pio_command(int port, uint8_t cmd);
+
+void pio_set_mode(int port, int mode);
+void pio_set_interrupts(int port, int control);
+void pio_set_interrupts_mask(int port, uint8_t mask);
+void pio_set_io(int port, uint8_t io);
+
+// uint8_t pio_read_data(int port);
+
+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/z80/kernel/include/types.h b/sw/z80/kernel/include/types.h
index c24b311..552b7e9 100644
--- a/sw/z80/kernel/include/types.h
+++ b/sw/z80/kernel/include/types.h
@@ -1,6 +1,8 @@
 #ifndef __TYPES_H__
 #define __TYPES_H__
 
+#define register_t  volatile unsigned char
+
 #define int8_t      char
 #define uint8_t     unsigned char
 #define int16_t     int
diff --git a/sw/z80/kernel/include/usart.h b/sw/z80/kernel/include/usart.h
new file mode 100644
index 0000000..3e5c070
--- /dev/null
+++ b/sw/z80/kernel/include/usart.h
@@ -0,0 +1,149 @@
+#ifndef __USART_H__
+#define __USART_H__
+
+#include "types.h"
+#include "devices.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
+
+
+/* this structure is only for internal usage */
+struct _usart_device
+{
+    register_t buffer;  // also used as LSB for divisor latch
+
+    struct IER 
+    {
+        volatile int received_data_interrupt :1;
+        volatile int transmitter_empty_interrupt :1;
+        volatile int receiver_line_status_interrupt :1;
+        volatile int modem_status_interrupt :1;
+        volatile int reserved :4;
+    } IER;
+
+    struct IIR
+    {
+        volatile int interrupt_pending :1;
+        volatile int interrupt_id :3;
+        volatile int reserved :2;
+        volatile int fifos :2;
+    } IIR;
+
+    struct FCR
+    {
+        volatile int fifo_enable :1;
+        volatile int receiver_fifo_rst :1;
+        volatile int trasmitter_fifo_rst :1;
+        volatile int dma_mode_select :1;
+        volatile int reserved :1;
+        volatile int receiver_trigger :2;
+    } FCR;
+
+    struct LCR
+    {
+        volatile int word_length :2;
+        volatile int stop_bits :1;
+        volatile int parity :1;
+        volatile int even_parity :1;
+        volatile int stick_parity :1;
+        volatile int break_control :1;
+        volatile int divisor_latch_access :1;
+    } LCR;
+
+    struct MCR
+    {
+        volatile int data_terminal_ready :1;
+        volatile int request_to_send :1;
+        volatile int out1;
+        volatile int out2;
+        volatile int loop;
+        volatile int autoflow :1;
+        volatile int reserved :2;
+    } MCR;
+
+    struct LSR 
+    {
+        volatile int data_ready :1;
+        volatile int overrun_error :1;
+        volatile int parity_error :1;
+        volatile int framing_error :1;
+        volatile int break_interrupt :1;
+        volatile int transmitter_holder_empty :1;
+        volatile int transmitter_empty :1;
+        volatile int fifo_recv_error :1;
+    } LSR;
+
+    struct MSR
+    {
+        volatile int delta_cts :1;
+        volatile int delta_data_set_ready :1;
+        volatile int trailing_edge_ring_indicator :1;
+        volatile int delta_data_carrier_detect :1;
+        volatile int clear_to_send :1;
+        volatile int data_set_ready :1;
+        volatile int ring_indicator :1;
+        volatile int data_carrier_detect :1;
+    } 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/z80/kernel/kernel.c b/sw/z80/kernel/kernel.c
index fe87c3d..3d5aeb6 100644
--- a/sw/z80/kernel/kernel.c
+++ b/sw/z80/kernel/kernel.c
@@ -1,10 +1,7 @@
 #include "types.h"
+#include "usart.h"
 
-
-void main(void)
+void kmain(void)
 {
-    int i, j = 20;
-    for (i = 0; i < 10; i++) {
-        j--;
-    }
+    usart_init(USART_BAUDRATE_9600, USART_PARITY_EVEN, USART_STOP_BITS_1);
 }
diff --git a/sw/z80/kernel/pio.c b/sw/z80/kernel/pio.c
new file mode 100644
index 0000000..4b9caee
--- /dev/null
+++ b/sw/z80/kernel/pio.c
@@ -0,0 +1,18 @@
+#include "pio.h"
+
+static uint8_t *pio_port = (uint8_t *) ADDR_DEV_PIO;
+static uint8_t *pio_ctrl = (uint8_t *) (ADDR_DEV_PIO + 2);
+
+void _pio_data(int port, uint8_t data)
+{
+    *(pio_port + port) = data;
+}
+
+void _pio_command(int port, uint8_t cmd)
+{
+    *(pio_ctrl + port) = cmd;
+}
+
+void pio_set_mode(int port, int mode)
+{
+}
diff --git a/sw/z80/kernel/usart.c b/sw/z80/kernel/usart.c
new file mode 100644
index 0000000..9ec6dbd
--- /dev/null
+++ b/sw/z80/kernel/usart.c
@@ -0,0 +1,91 @@
+#include "usart.h"
+
+static 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/z80/libc/include/stdio.h b/sw/z80/libc/include/stdio.h
new file mode 100644
index 0000000..b31cdfd
--- /dev/null
+++ b/sw/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/z80/libc/include/string.h b/sw/z80/libc/include/string.h
new file mode 100644
index 0000000..f224c87
--- /dev/null
+++ b/sw/z80/libc/include/string.h
@@ -0,0 +1,8 @@
+#ifndef __STRING_H__
+#define __STRING_H__
+
+#include "types.h"
+
+void *memcpy(void *dest, const void *src, size_t n);
+
+#endif
diff --git a/sw/z80/libc/stdio.c b/sw/z80/libc/stdio.c
new file mode 100644
index 0000000..c2548d6
--- /dev/null
+++ b/sw/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/z80/libc/string.c b/sw/z80/libc/string.c
new file mode 100644
index 0000000..fd6a7ff
--- /dev/null
+++ b/sw/z80/libc/string.c
@@ -0,0 +1,13 @@
+#include "string.h"
+
+void *memcpy(void *dest, void *src, size_t n)
+{
+    char *dp = dest;
+    char *sp = src;
+
+    while (n--) {
+        *dp++ = *sp++;
+    }
+
+    return dest;
+}