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b69da5652659dde88c4afd425962c7839b4a0133
z80/zx_disk.cpp
Raimon Zamora b69da56526 - Afegit lagueirtofile pa compilar FASTuosament 
- [NEW] [zx_disk] funcions de debug
- [FIX] current_byte era un uint8_t i tenia que ser al menys uint16_t, per això fallava el READ DATA.
2025-08-07 16:06:42 +02:00

679 lines
23 KiB
C++
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#include "zx_disk.h"
#include "z80.h"
#include <stdio.h>
#include <stdlib.h>
#define ZX_FDC_MODE_IDLE 0
#define ZX_FDC_MODE_COMMAND 1
#define ZX_FDC_MODE_EXECUTION 2
#define ZX_FDC_MODE_RESULT 3
#define ZX_FDC_DATA_DIRECTION_INPUT 0x00
#define ZX_FDC_DATA_DIRECTION_OUTPUT 0x40
#define ZX_FDC_COMMAND_MASK 0x1F
#define ZX_FDC_COMMAND_SPECIFY 0x03
#define ZX_FDC_COMMAND_SENSE_DRIVE_STATUS 0x04
#define ZX_FDC_COMMAND_RECALIBRATE 0x07
#define ZX_FDC_COMMAND_SENSE_INTERRUPT_STATUS 0x08
#define ZX_FDC_COMMAND_SEEK 0x0F
#define ZX_FDC_COMMAND_READ_ID 0x0A
#define ZX_FDC_COMMAND_READ_DATA 0x06
#define ZX_FDC_MAIN_DRIVE0_BUSY 1
#define ZX_FDC_MAIN_DRIVE1_BUSY 2
#define ZX_FDC_MAIN_DRIVE2_BUSY 4
#define ZX_FDC_MAIN_DRIVE3_BUSY 8
#define ZX_FDC_MAIN_BUSY 16
#define ZX_FDC_MAIN_EXEC_MODE 32
#define ZX_FDC_MAIN_DATA_DIR 64 // 0: CPU->FDC 1: FDC->CPU
#define ZX_FDC_MAIN_DATA_READY 128
namespace zx_disk
{
struct sector_t
{
uint8_t id { 0 };
uint8_t size { 0 };
uint8_t st1 { 0 };
uint8_t st2 { 0 };
uint16_t data_length{ 0 };
uint8_t *data { nullptr };
};
struct track_t
{
uint8_t size { 0 };
uint8_t sector_size { 0 };
uint8_t num_sectors { 0 };
uint8_t filler_byte { 0x35 };
sector_t *sectors { nullptr };
};
struct disk_t
{
uint8_t num_tracks { 0 };
uint8_t num_sides { 0 };
track_t *tracks { nullptr };
};
disk_t disk;
uint8_t mode = ZX_FDC_MODE_IDLE;
uint8_t call_count = 0;
//uint8_t data_direction = 0x00; // 0x40
uint8_t fdd0busy = 0;
bool command_success = false;
uint8_t srt, hlt, hut, nd;
bool seeking = false;
uint8_t current_head = 0;
uint8_t current_drive = 0;
uint8_t current_track = 0;
uint8_t current_sector = 0;
uint16_t current_byte = 0;
uint16_t bytes_to_read = 0;
uint8_t eot = 0;
uint8_t st1 = 0;
uint8_t st2 = 0;
int zx_fdc_main_status_port_in(int port);
int zx_fdc_data_port_in(int port);
void zx_fdc_data_port_out(int port, int val);
void init()
{
z80::connect_port(0x2ffd, 0xf002, zx_fdc_main_status_port_in, nullptr);
z80::connect_port(0x3ffd, 0xf002, zx_fdc_data_port_in, zx_fdc_data_port_out);
load("goldenaxe1.dsk");
}
void reset()
{
}
void load(const char *filename)
{
FILE *f = fopen(filename, "rb");
if (!f) return;
fseek(f, 0, SEEK_END);
const int file_size = ftell(f);
fseek(f, 0, SEEK_SET);
uint8_t *buffer = (uint8_t*)malloc(file_size);
fread(buffer, file_size, 1, f);
fclose(f);
if (disk.tracks) {
for (int i=0; i<disk.num_tracks; ++i) {
for (int j=0; j<disk.tracks[i].num_sectors; ++j) {
free(disk.tracks[i].sectors[i].data);
}
free(disk.tracks[i].sectors);
}
free(disk.tracks);
}
// Hardcoded to read extended disks. Also, no security checks at all. Fuck the police.
disk.num_tracks = buffer[0x30];
disk.num_sides = buffer[0x31];
disk.tracks = (track_t*)malloc(disk.num_tracks*sizeof(track_t));
for (int i=0; i<disk.num_tracks; ++i) disk.tracks[i].size = buffer[0x34+i];
uint32_t pos = 0x100;
for (int i=0; i<disk.num_tracks; ++i)
{
track_t &track = disk.tracks[i];
track.sector_size = buffer[pos+0x14];
track.num_sectors = buffer[pos+0x15];
track.filler_byte = buffer[pos+0x17];
track.sectors = (sector_t*)malloc(track.num_sectors*sizeof(sector_t));
pos += 0x18;
for (int j=0; j<track.num_sectors; ++j)
{
sector_t &sector = track.sectors[j];
sector.id = buffer[pos+0x02];
sector.size = buffer[pos+0x03];
sector.st1 = buffer[pos+0x04];
sector.st2 = buffer[pos+0x05];
sector.data_length = buffer[pos+0x06] + uint16_t((buffer[pos+0x07])<<8);
if (sector.data_length==0) sector.data_length = uint16_t(sector.size)<<8;
pos += 8;
}
if (pos&0xff) pos = (pos & 0xffffff00) + 0x100;
for (int j=0; j<track.num_sectors; ++j)
{
sector_t &sector = track.sectors[j];
const uint16_t size = uint16_t(sector.size)<<8;
sector.data = (uint8_t*)malloc(size);
for (int k=0; k<size; ++k) sector.data[k] = buffer[pos++];
}
}
}
uint8_t main_status_register()
{
const uint8_t val = (fdd0busy) |
((mode==ZX_FDC_MODE_IDLE) ? 0x00 : 0x10) |
((mode==ZX_FDC_MODE_EXECUTION) ? 0x20 : 0x00) |
((mode==ZX_FDC_MODE_RESULT) ? 0x40 : 0x00) |
(0x80);
return val;
}
int zx_fdc_main_status_port_in(int port)
{
//if (mode != ZX_FDC_MODE_EXECUTION) printf("FDC port 0x2ffd IN\n");
return main_status_register();
}
uint8_t ST0()
{
return current_drive | (current_head<<2) | (seeking ? 0x20 : 0x00) | (fdd0busy ? 0x00 : 0x80);
}
uint8_t ST3()
{
const bool ready = (current_head==0) && (current_drive==0);
return current_drive | (current_head<<2) | ((current_track==0)?0x10:0) |
(ready?0x20:0) | 0x00; // TS
}
void start_command(uint8_t command);
uint8_t (*process_current_command)(uint8_t) = nullptr;
uint8_t process_command_unknown(uint8_t command);
uint8_t process_command_specify(uint8_t command);
uint8_t process_command_sense_drive_status(uint8_t command);
uint8_t process_command_recalibrate(uint8_t command);
uint8_t process_command_sense_interrupt_status(uint8_t command);
uint8_t process_command_seek(uint8_t command);
uint8_t process_command_read_id(uint8_t command);
uint8_t process_command_read_data(uint8_t command);
int zx_fdc_data_port_in(int port)
{
//if (mode != ZX_FDC_MODE_EXECUTION) printf("FDC port 0x3ffd IN\n");
if (mode == ZX_FDC_MODE_COMMAND) {
printf("IGNORED!\n");
return 0;
}
if (process_current_command) return process_current_command(0);
return 0;
}
void zx_fdc_data_port_out(int port, int val)
{
//printf("FDC port 0x3ffd OUT: 0x%02x\n", val);
if (mode == ZX_FDC_MODE_RESULT) {
printf("IGNORED!\n");
return;
}
if (process_current_command)
process_current_command(val);
else
start_command(val);
}
void start_command(uint8_t command)
{
if ((fdd0busy) && ((command & ZX_FDC_COMMAND_MASK) != ZX_FDC_COMMAND_SENSE_INTERRUPT_STATUS)) return;
mode = ZX_FDC_MODE_COMMAND;
call_count = 1;
debug::composeCommand(command);
switch(command & ZX_FDC_COMMAND_MASK)
{
case ZX_FDC_COMMAND_SPECIFY:
process_current_command = process_command_specify;
break;
case ZX_FDC_COMMAND_SENSE_DRIVE_STATUS:
process_current_command = process_command_sense_drive_status;
break;
case ZX_FDC_COMMAND_RECALIBRATE:
process_current_command = process_command_recalibrate;
fdd0busy = 1;
break;
case ZX_FDC_COMMAND_SENSE_INTERRUPT_STATUS:
process_current_command = process_command_sense_interrupt_status;
mode = ZX_FDC_MODE_RESULT;
call_count = 0;
break;
case ZX_FDC_COMMAND_SEEK:
process_current_command = process_command_seek;
fdd0busy = 1;
seeking = true;
break;
case ZX_FDC_COMMAND_READ_ID:
process_current_command = process_command_read_id;
break;
case ZX_FDC_COMMAND_READ_DATA:
process_current_command = process_command_read_data;
break;
default:
{
debug::printCommand();
process_current_command = process_command_unknown;
mode = ZX_FDC_MODE_RESULT;
call_count = 0;
}
}
}
// ===================================================================
// FDC COMMAND: UNKNOWN
// ===================================================================
uint8_t process_command_unknown(uint8_t command)
{
process_current_command = nullptr;
mode = ZX_FDC_MODE_IDLE;
const uint8_t val = ST0();
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
debug::printResult();
return val;
}
// ===================================================================
// FDC COMMAND: SPECIFY (0x03)
// ===================================================================
uint8_t process_command_specify(uint8_t command)
{
debug::composeCommand(command);
switch (call_count) {
case 1:
srt = (command & 0xf0) >> 4;
hut = command & 0x0f;
call_count++;
break;
case 2:
hlt = (command & 0xfe) >> 1;
nd = command & 0x01;
call_count=0;
process_current_command = nullptr;
mode = ZX_FDC_MODE_IDLE;
debug::printCommand();
break;
}
return 0;
}
// ===================================================================
// FDC COMMAND: SENSE DRIVE STATUS (0x04)
// ===================================================================
uint8_t process_command_sense_drive_status(uint8_t command)
{
switch (mode)
{
case ZX_FDC_MODE_COMMAND:
current_head = (command & 0x4)>>2;
current_drive = command & 0x3;
call_count = 0;
mode = ZX_FDC_MODE_RESULT;
debug::composeCommand(command);
debug::printCommand();
break;
case ZX_FDC_MODE_RESULT:
{
process_current_command = nullptr;
mode = ZX_FDC_MODE_IDLE;
const uint8_t val = ST3();
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
debug::printResult();
return val;
}
}
return 0;
}
// ===================================================================
// FDC COMMAND: RECALIBRATE (0x07)
// ===================================================================
uint8_t process_command_recalibrate(uint8_t command)
{
switch (mode)
{
case ZX_FDC_MODE_COMMAND:
current_drive = command & 0x3;
call_count = 0;
current_track = 0;
seeking = true;
process_current_command = nullptr;
mode = ZX_FDC_MODE_IDLE;
debug::composeCommand(command);
debug::printCommand();
break;
}
return 0;
}
// ===================================================================
// FDC COMMAND: SENSE INTERRUPT STATUS (0x08)
// ===================================================================
uint8_t process_command_sense_interrupt_status(uint8_t command)
{
switch (call_count)
{
case 0:
{
debug::printCommand();
call_count++;
const uint8_t val = ST0();
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 1:
process_current_command = nullptr;
fdd0busy = 0;
seeking = false;
call_count = 0;
mode = ZX_FDC_MODE_IDLE;
//printf("--> (returning 0x%02x)\n", current_track);
debug::composeResult(current_track);
debug::printResult();
return current_track;
}
return 0;
}
// ===================================================================
// FDC COMMAND: SEEK (0x0F)
// ===================================================================
uint8_t process_command_seek(uint8_t command)
{
debug::composeCommand(command);
switch (call_count)
{
case 1:
{
current_head = (command & 0x4)>>2;
current_drive = command & 0x3;
call_count++;
break;
}
case 2:
current_track = command;
process_current_command = nullptr;
call_count = 0;
mode = ZX_FDC_MODE_IDLE;
debug::printCommand();
break;
}
return 0;
}
// ===================================================================
// FDC COMMAND: READ ID (0x0A)
// ===================================================================
uint8_t process_command_read_id(uint8_t command)
{
switch (mode)
{
case ZX_FDC_MODE_COMMAND:
current_head = (command & 0x4)>>2;
current_drive = command & 0x3;
call_count = 0;
current_sector = 0;
mode = ZX_FDC_MODE_RESULT;
debug::composeCommand(command);
debug::printCommand();
break;
case ZX_FDC_MODE_RESULT:
{
switch (call_count)
{
case 0:
{
call_count++;
fdd0busy = 1;
const uint8_t val = ST0();
fdd0busy = 0;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 1:
{
call_count++;
const uint8_t val = 0x00; // ST1
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 2:
{
call_count++;
const uint8_t val = 0x00; // ST2
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 3:
{
call_count++;
const uint8_t val = current_track;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 4:
{
call_count++;
const uint8_t val = current_head;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 5:
{
call_count++;
const uint8_t val = current_sector+1;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 6:
{
call_count = 0;
process_current_command = nullptr;
mode = ZX_FDC_MODE_IDLE;
const uint8_t val = disk.tracks[current_track].sectors[current_sector].size;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
debug::printResult();
return val;
}
}
}
}
return 0;
}
// ===================================================================
// FDC COMMAND: READ DATA (0x06)
// ===================================================================
uint8_t process_command_read_data(uint8_t command)
{
switch (mode)
{
case ZX_FDC_MODE_COMMAND:
debug::composeCommand(command);
switch (call_count)
{
case 1:
call_count++;
current_head = (command & 0x4)>>2;
current_drive = command & 0x3;
break;
case 2:
call_count++;
current_track = command;
break;
case 3:
call_count++;
current_head = command;
break;
case 4:
call_count++;
current_sector = command-1;
break;
case 5:
call_count++;
bytes_to_read = command;
break;
case 6:
call_count++;
eot = command;
break;
case 7:
call_count++;
break;
case 8:
if ( (bytes_to_read==0) && (command != 0xff) ) bytes_to_read = command;
bytes_to_read = bytes_to_read << 8;
current_byte = 0;
call_count = 0;
mode = ZX_FDC_MODE_EXECUTION;
debug::printCommand();
break;
}
break;
case ZX_FDC_MODE_EXECUTION:
{
const uint8_t val = disk.tracks[current_track].sectors[current_sector].data[current_byte];
current_byte++;
if (current_byte == disk.tracks[current_track].sectors[current_sector].data_length) {
current_byte = 0;
current_sector++;
if (current_sector == disk.tracks[current_track].num_sectors) {
current_track++;
current_sector = 0;
}
}
bytes_to_read--;
if (bytes_to_read==0) {
st1 = disk.tracks[current_track].sectors[current_sector].st1;
st2 = disk.tracks[current_track].sectors[current_sector].st2;
mode = ZX_FDC_MODE_RESULT;
}
return val;
break;
}
case ZX_FDC_MODE_RESULT:
{
switch (call_count)
{
case 0:
{
call_count++;
fdd0busy = 1;
const uint8_t val = ST0();
fdd0busy = 0;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 1:
{
call_count++;
const uint8_t val = st1;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 2:
{
call_count++;
const uint8_t val = st2;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 3:
{
call_count++;
const uint8_t val = current_track;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 4:
{
call_count++;
const uint8_t val = current_head;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 5:
{
call_count++;
const uint8_t val = current_sector+1;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
return val;
}
case 6:
{
call_count = 0;
process_current_command = nullptr;
mode = ZX_FDC_MODE_IDLE;
const uint8_t val = disk.tracks[current_track].sectors[current_sector].size;
//printf("--> (returning 0x%02x)\n", val);
debug::composeResult(val);
debug::printResult();
return val;
}
}
break;
}
}
return 0;
}
namespace debug
{
uint8_t values[9];
uint8_t num_values = 0;
void composeCommand(const uint8_t value)
{
values[num_values++] = value;
}
void composeResult(const uint8_t value)
{
values[num_values++] = value;
}
void printCommand()
{
printf("FDC COMMAND %02x: ( ", values[0] & 0x1f);
for (int i=0; i<num_values; ++i) printf("%02x ", values[i]);
printf(")\n");
num_values = 0;
}
void printResult()
{
printf("FDC RESULT: ( ");
for (int i=0; i<num_values; ++i) printf("%02x ", values[i]);
printf(")\n");
num_values = 0;
}
}
}
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