Raimon Zamora
90b34749d1
- [NEW] [zx_disk] SENSE INTERRUPT STATUS command (0x08) - [ONGOING] [zx_disk] SEEK command (0x0f)
284 lines
8.6 KiB
C++
284 lines
8.6 KiB
C++
#include "zx_disk.h"
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#include "z80.h"
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#include <stdio.h>
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#define ZX_FDC_MODE_IDLE 0
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#define ZX_FDC_MODE_COMMAND 1
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#define ZX_FDC_MODE_EXECUTION 2
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#define ZX_FDC_MODE_RESULT 3
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#define ZX_FDC_DATA_DIRECTION_INPUT 0x00
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#define ZX_FDC_DATA_DIRECTION_OUTPUT 0x40
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#define ZX_FDC_COMMAND_MASK 0x1F
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#define ZX_FDC_COMMAND_SPECIFY 0x03
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#define ZX_FDC_COMMAND_SENSE_DRIVE_STATUS 0x04
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#define ZX_FDC_COMMAND_RECALIBRATE 0x07
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#define ZX_FDC_COMMAND_SENSE_INTERRUPT_STATUS 0x08
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#define ZX_FDC_COMMAND_SEEK 0x0F
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#define ZX_FDC_MAIN_DRIVE0_BUSY 1
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#define ZX_FDC_MAIN_DRIVE1_BUSY 2
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#define ZX_FDC_MAIN_DRIVE2_BUSY 4
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#define ZX_FDC_MAIN_DRIVE3_BUSY 8
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#define ZX_FDC_MAIN_BUSY 16
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#define ZX_FDC_MAIN_EXEC_MODE 32
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#define ZX_FDC_MAIN_DATA_DIR 64 // 0: CPU->FDC 1: FDC->CPU
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#define ZX_FDC_MAIN_DATA_READY 128
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namespace zx_disk
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{
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uint8_t mode = ZX_FDC_MODE_IDLE;
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uint8_t call_count = 0;
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//uint8_t data_direction = 0x00; // 0x40
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uint8_t fdd0busy = 0;
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uint8_t srt, hlt, hut, nd;
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bool seeking = false;
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uint8_t current_head = 0;
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uint8_t current_drive = 0;
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uint8_t current_track = 0;
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int zx_fdc_main_status_port_in(int port);
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int zx_fdc_data_port_in(int port);
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void zx_fdc_data_port_out(int port, int val);
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void init()
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{
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z80::connect_port(0x2ffd, 0xf002, zx_fdc_main_status_port_in, nullptr);
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z80::connect_port(0x3ffd, 0xf002, zx_fdc_data_port_in, zx_fdc_data_port_out);
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}
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void reset()
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{
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}
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uint8_t main_status_register()
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{
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const uint8_t val = (fdd0busy) |
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((mode==ZX_FDC_MODE_IDLE) ? 0x00 : 0x10) |
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((mode==ZX_FDC_MODE_EXECUTION) ? 0x20 : 0x00) |
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((mode==ZX_FDC_MODE_RESULT) ? 0x40 : 0x00) |
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(0x80);
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return val;
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}
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int zx_fdc_main_status_port_in(int port)
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{
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printf("FDC port 0x2ffd IN\n");
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return main_status_register();
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}
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uint8_t ST0()
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{
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return current_drive | (current_head<<2) | (seeking ? 0x20 : 0x00) | (fdd0busy ? 0x00 : 0x40);
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}
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uint8_t ST3()
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{
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return current_drive | (current_head<<2) | 0x38; // ST3
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}
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void start_command(uint8_t command);
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uint8_t (*process_current_command)(uint8_t) = nullptr;
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uint8_t process_command_unknown(uint8_t command);
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uint8_t process_command_specify(uint8_t command);
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uint8_t process_command_sense_drive_status(uint8_t command);
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uint8_t process_command_recalibrate(uint8_t command);
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uint8_t process_command_sense_interrupt_status(uint8_t command);
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uint8_t process_command_seek(uint8_t command);
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int zx_fdc_data_port_in(int port)
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{
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printf("FDC port 0x3ffd IN\n");
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if (mode == ZX_FDC_MODE_COMMAND) {
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printf("IGNORED!\n");
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return 0;
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}
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if (process_current_command) return process_current_command(0);
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return 0;
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}
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void zx_fdc_data_port_out(int port, int val)
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{
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printf("FDC port 0x3ffd OUT: 0x%02x\n", val);
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if (mode == ZX_FDC_MODE_RESULT) {
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printf("IGNORED!\n");
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return;
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}
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if (process_current_command)
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process_current_command(val);
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else
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start_command(val & ZX_FDC_COMMAND_MASK);
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}
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void start_command(uint8_t command)
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{
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if ((fdd0busy) && (command != ZX_FDC_COMMAND_SENSE_INTERRUPT_STATUS)) return;
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mode = ZX_FDC_MODE_COMMAND;
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call_count = 1;
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switch(command)
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{
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case ZX_FDC_COMMAND_SPECIFY:
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process_current_command = process_command_specify;
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break;
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case ZX_FDC_COMMAND_SENSE_DRIVE_STATUS:
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process_current_command = process_command_sense_drive_status;
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break;
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case ZX_FDC_COMMAND_RECALIBRATE:
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process_current_command = process_command_recalibrate;
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fdd0busy = 1;
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break;
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case ZX_FDC_COMMAND_SENSE_INTERRUPT_STATUS:
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process_current_command = process_command_sense_interrupt_status;
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mode = ZX_FDC_MODE_RESULT;
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call_count = 0;
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break;
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case ZX_FDC_COMMAND_SEEK:
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process_current_command = process_command_seek;
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fdd0busy = 1;
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seeking = true;
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break;
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default:
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{
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process_current_command = process_command_unknown;
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mode = ZX_FDC_MODE_RESULT;
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call_count = 0;
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}
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}
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}
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// ===================================================================
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// FDC COMMAND: UNKNOWN
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// ===================================================================
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uint8_t process_command_unknown(uint8_t command)
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{
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process_current_command = nullptr;
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mode = ZX_FDC_MODE_IDLE;
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const uint8_t val = ST0();
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printf("--> (returning 0x%02x)\n", val);
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return val;
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}
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// ===================================================================
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// FDC COMMAND: SPECIFY (0x03)
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// ===================================================================
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uint8_t process_command_specify(uint8_t command)
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{
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switch (call_count) {
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case 1:
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srt = (command & 0xf0) >> 4;
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hut = command & 0x0f;
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call_count++;
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break;
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case 2:
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hlt = (command & 0xfe) >> 1;
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nd = command & 0x01;
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call_count=0;
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process_current_command = nullptr;
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mode = ZX_FDC_MODE_IDLE;
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break;
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}
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return 0;
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}
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// ===================================================================
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// FDC COMMAND: SENSE DRIVE STATUS (0x04)
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// ===================================================================
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uint8_t process_command_sense_drive_status(uint8_t command)
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{
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switch (mode)
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{
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case ZX_FDC_MODE_COMMAND:
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current_head = (command & 0x4)>>2;
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current_drive = command & 0x3;
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call_count = 0;
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mode = ZX_FDC_MODE_RESULT;
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break;
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case ZX_FDC_MODE_RESULT:
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{
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process_current_command = nullptr;
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mode = ZX_FDC_MODE_IDLE;
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const uint8_t val = ST3();
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printf("--> (returning 0x%02x)\n", val);
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return val;
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}
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}
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return 0;
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}
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// ===================================================================
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// FDC COMMAND: RECALIBRATE (0x07)
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// ===================================================================
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uint8_t process_command_recalibrate(uint8_t command)
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{
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switch (mode)
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{
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case ZX_FDC_MODE_COMMAND:
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current_drive = command & 0x3;
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call_count = 0;
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current_track = 0;
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process_current_command = nullptr;
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mode = ZX_FDC_MODE_IDLE;
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break;
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}
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return 0;
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}
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// ===================================================================
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// FDC COMMAND: SENSE INTERRUPT STATUS (0x08)
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// ===================================================================
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uint8_t process_command_sense_interrupt_status(uint8_t command)
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{
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switch (call_count)
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{
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case 0:
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{
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call_count++;
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const uint8_t val = ST0();
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printf("--> (returning 0x%02x)\n", val);
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return val;
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}
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case 1:
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process_current_command = nullptr;
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fdd0busy = 0;
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seeking = false;
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call_count = 0;
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mode = ZX_FDC_MODE_IDLE;
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printf("--> (returning 0x%02x)\n", current_track);
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return current_track;
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}
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return 0;
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}
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// ===================================================================
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// FDC COMMAND: SEEK (0x0F)
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// ===================================================================
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uint8_t process_command_seek(uint8_t command)
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{
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switch (call_count)
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{
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case 1:
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{
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current_head = (command & 0x4)>>2;
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current_drive = command & 0x3;
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call_count++;
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break;
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}
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case 2:
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current_track = command;
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process_current_command = nullptr;
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call_count = 0;
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mode = ZX_FDC_MODE_IDLE;
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break;
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}
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return 0;
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}
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}
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