frodo-wii/Src/1541job.cpp
2008-12-31 16:16:24 +00:00

463 lines
9.4 KiB
C++

/*
* 1541job.cpp - Emulation of 1541 GCR disk reading/writing
*
* Frodo (C) 1994-1997,2002 Christian Bauer
*
*
* Notes:
* ------
*
* - This is only used for processor-level 1541 emulation.
* It simulates the 1541 disk controller hardware (R/W head,
* GCR reading/writing).
* - The preferences settings for drive 8 are used to
* specify the .d64 file
*
* Incompatibilities:
* ------------------
*
* - No GCR writing possible (WriteSector is a ROM patch)
* - Programs depending on the exact timing of head movement/disk
* rotation don't work
* - The .d64 error info is unused
*/
#include "sysdeps.h"
#include "1541job.h"
#include "CPU1541.h"
#include "Prefs.h"
// Number of tracks/sectors
const int NUM_TRACKS = 35;
const int NUM_SECTORS = 683;
// Size of GCR encoded data
const int GCR_SECTOR_SIZE = 1+10+9+1+325+8; // SYNC Header Gap SYNC Data Gap (should be 5 SYNC bytes each)
const int GCR_TRACK_SIZE = GCR_SECTOR_SIZE * 21; // Each track in gcr_data has 21 sectors
const int GCR_DISK_SIZE = GCR_TRACK_SIZE * NUM_TRACKS;
// Job return codes
const int RET_OK = 1; // No error
const int RET_NOT_FOUND = 2; // Block not found
const int RET_NOT_READY = 15; // Drive not ready
// Number of sectors of each track
const int num_sectors[36] = {
0,
21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,
19,19,19,19,19,19,19,
18,18,18,18,18,18,
17,17,17,17,17
};
// Sector offset of start of track in .d64 file
const int sector_offset[36] = {
0,
0,21,42,63,84,105,126,147,168,189,210,231,252,273,294,315,336,
357,376,395,414,433,452,471,
490,508,526,544,562,580,
598,615,632,649,666
};
/*
* Constructor: Open .d64 file if processor-level 1541
* emulation is enabled
*/
Job1541::Job1541(uint8 *ram1541) : ram(ram1541)
{
the_file = NULL;
gcr_data = gcr_ptr = gcr_track_start = new uint8[GCR_DISK_SIZE];
gcr_track_end = gcr_track_start + GCR_TRACK_SIZE;
current_halftrack = 2;
disk_changed = true;
if (ThePrefs.Emul1541Proc)
open_d64_file(ThePrefs.DrivePath[0]);
}
/*
* Destructor: Close .d64 file
*/
Job1541::~Job1541()
{
close_d64_file();
delete[] gcr_data;
}
/*
* Preferences may have changed
*/
void Job1541::NewPrefs(Prefs *prefs)
{
// 1541 emulation turned off?
if (!prefs->Emul1541Proc)
close_d64_file();
// 1541 emulation turned on?
else if (!ThePrefs.Emul1541Proc && prefs->Emul1541Proc)
open_d64_file(prefs->DrivePath[0]);
// .d64 file name changed?
else if (strcmp(ThePrefs.DrivePath[0], prefs->DrivePath[0])) {
close_d64_file();
open_d64_file(prefs->DrivePath[0]);
disk_changed = true;
}
}
/*
* Open .d64 file
*/
void Job1541::open_d64_file(char *filepath)
{
long size;
uint8 magic[4];
uint8 bam[256];
// Clear GCR buffer
memset(gcr_data, 0x55, GCR_DISK_SIZE);
// Try opening the file for reading/writing first, then for reading only
write_protected = false;
the_file = fopen(filepath, "rb+");
if (the_file == NULL) {
write_protected = true;
the_file = fopen(filepath, "rb");
}
if (the_file != NULL) {
// Check length
fseek(the_file, 0, SEEK_END);
if ((size = ftell(the_file)) < NUM_SECTORS * 256) {
fclose(the_file);
the_file = NULL;
return;
}
// x64 image?
fseek(the_file, 0, SEEK_SET);
fread(&magic, 4, 1, the_file);
if (magic[0] == 0x43 && magic[1] == 0x15 && magic[2] == 0x41 && magic[3] == 0x64)
image_header = 64;
else
image_header = 0;
// Preset error info (all sectors no error)
memset(error_info, 1, NUM_SECTORS);
// Load sector error info from .d64 file, if present
if (!image_header && size == NUM_SECTORS * 257) {
fseek(the_file, NUM_SECTORS * 256, SEEK_SET);
fread(&error_info, NUM_SECTORS, 1, the_file);
};
// Read BAM and get ID
read_sector(18, 0, bam);
id1 = bam[162];
id2 = bam[163];
// Create GCR encoded disk data from image
disk2gcr();
}
}
/*
* Close .d64 file
*/
void Job1541::close_d64_file(void)
{
if (the_file != NULL) {
fclose(the_file);
the_file = NULL;
}
}
/*
* Write sector to disk (1541 ROM patch)
*/
void Job1541::WriteSector(void)
{
int track = ram[0x18];
int sector = ram[0x19];
uint16 buf = ram[0x30] | (ram[0x31] << 8);
if (buf <= 0x0700)
if (write_sector(track, sector, ram + buf))
sector2gcr(track, sector);
}
/*
* Format one track (1541 ROM patch)
*/
void Job1541::FormatTrack(void)
{
int track = ram[0x51];
// Get new ID
uint8 bufnum = ram[0x3d];
id1 = ram[0x12 + bufnum];
id2 = ram[0x13 + bufnum];
// Create empty block
uint8 buf[256];
memset(buf, 1, 256);
buf[0] = 0x4b;
// Write block to all sectors on track
for(int sector=0; sector<num_sectors[track]; sector++) {
write_sector(track, sector, buf);
sector2gcr(track, sector);
}
// Clear error info (all sectors no error)
if (track == 35)
memset(error_info, 1, NUM_SECTORS);
// Write error_info to disk?
}
/*
* Read sector (256 bytes)
* true: success, false: error
*/
bool Job1541::read_sector(int track, int sector, uint8 *buffer)
{
int offset;
// Convert track/sector to byte offset in file
if ((offset = offset_from_ts(track, sector)) < 0)
return false;
#ifdef AMIGA
if (offset != ftell(the_file))
fseek(the_file, offset + image_header, SEEK_SET);
#else
fseek(the_file, offset + image_header, SEEK_SET);
#endif
fread(buffer, 256, 1, the_file);
return true;
}
/*
* Write sector (256 bytes) !! -> GCR
* true: success, false: error
*/
bool Job1541::write_sector(int track, int sector, uint8 *buffer)
{
int offset;
// Convert track/sector to byte offset in file
if ((offset = offset_from_ts(track, sector)) < 0)
return false;
#ifdef AMIGA
if (offset != ftell(the_file))
fseek(the_file, offset + image_header, SEEK_SET);
#else
fseek(the_file, offset + image_header, SEEK_SET);
#endif
fwrite(buffer, 256, 1, the_file);
return true;
}
/*
* Convert track/sector to offset
*/
int Job1541::secnum_from_ts(int track, int sector)
{
return sector_offset[track] + sector;
}
int Job1541::offset_from_ts(int track, int sector)
{
if ((track < 1) || (track > NUM_TRACKS) ||
(sector < 0) || (sector >= num_sectors[track]))
return -1;
return (sector_offset[track] + sector) << 8;
}
/*
* Convert 4 bytes to 5 GCR encoded bytes
*/
const uint16 gcr_table[16] = {
0x0a, 0x0b, 0x12, 0x13, 0x0e, 0x0f, 0x16, 0x17,
0x09, 0x19, 0x1a, 0x1b, 0x0d, 0x1d, 0x1e, 0x15
};
void Job1541::gcr_conv4(uint8 *from, uint8 *to)
{
uint16 g;
g = (gcr_table[*from >> 4] << 5) | gcr_table[*from & 15];
*to++ = g >> 2;
*to = (g << 6) & 0xc0;
from++;
g = (gcr_table[*from >> 4] << 5) | gcr_table[*from & 15];
*to++ |= (g >> 4) & 0x3f;
*to = (g << 4) & 0xf0;
from++;
g = (gcr_table[*from >> 4] << 5) | gcr_table[*from & 15];
*to++ |= (g >> 6) & 0x0f;
*to = (g << 2) & 0xfc;
from++;
g = (gcr_table[*from >> 4] << 5) | gcr_table[*from & 15];
*to++ |= (g >> 8) & 0x03;
*to = g;
}
/*
* Create GCR encoded disk data from image
*/
void Job1541::sector2gcr(int track, int sector)
{
uint8 block[256];
uint8 buf[4];
uint8 *p = gcr_data + (track-1) * GCR_TRACK_SIZE + sector * GCR_SECTOR_SIZE;
read_sector(track, sector, block);
// Create GCR header
*p++ = 0xff; // SYNC
buf[0] = 0x08; // Header mark
buf[1] = sector ^ track ^ id2 ^ id1; // Checksum
buf[2] = sector;
buf[3] = track;
gcr_conv4(buf, p);
buf[0] = id2;
buf[1] = id1;
buf[2] = 0x0f;
buf[3] = 0x0f;
gcr_conv4(buf, p+5);
p += 10;
memset(p, 0x55, 9); // Gap
p += 9;
// Create GCR data
uint8 sum;
*p++ = 0xff; // SYNC
buf[0] = 0x07; // Data mark
sum = buf[1] = block[0];
sum ^= buf[2] = block[1];
sum ^= buf[3] = block[2];
gcr_conv4(buf, p);
p += 5;
for (int i=3; i<255; i+=4) {
sum ^= buf[0] = block[i];
sum ^= buf[1] = block[i+1];
sum ^= buf[2] = block[i+2];
sum ^= buf[3] = block[i+3];
gcr_conv4(buf, p);
p += 5;
}
sum ^= buf[0] = block[255];
buf[1] = sum; // Checksum
buf[2] = 0;
buf[3] = 0;
gcr_conv4(buf, p);
p += 5;
memset(p, 0x55, 8); // Gap
}
void Job1541::disk2gcr(void)
{
// Convert all tracks and sectors
for (int track=1; track<=NUM_TRACKS; track++)
for(int sector=0; sector<num_sectors[track]; sector++)
sector2gcr(track, sector);
}
/*
* Move R/W head out (lower track numbers)
*/
void Job1541::MoveHeadOut(void)
{
if (current_halftrack == 2)
return;
current_halftrack--;
#ifndef __riscos__
printf("Head move %d\n", current_halftrack);
#endif
gcr_ptr = gcr_track_start = gcr_data + ((current_halftrack >> 1) - 1) * GCR_TRACK_SIZE;
gcr_track_end = gcr_track_start + num_sectors[current_halftrack >> 1] * GCR_SECTOR_SIZE;
}
/*
* Move R/W head in (higher track numbers)
*/
void Job1541::MoveHeadIn(void)
{
if (current_halftrack == NUM_TRACKS*2)
return;
current_halftrack++;
#ifndef __riscos__
printf("Head move %d\n", current_halftrack);
#endif
gcr_ptr = gcr_track_start = gcr_data + ((current_halftrack >> 1) - 1) * GCR_TRACK_SIZE;
gcr_track_end = gcr_track_start + num_sectors[current_halftrack >> 1] * GCR_SECTOR_SIZE;
}
/*
* Get state
*/
void Job1541::GetState(Job1541State *state)
{
state->current_halftrack = current_halftrack;
state->gcr_ptr = gcr_ptr - gcr_data;
state->write_protected = write_protected;
state->disk_changed = disk_changed;
}
/*
* Set state
*/
void Job1541::SetState(Job1541State *state)
{
current_halftrack = state->current_halftrack;
gcr_ptr = gcr_data + state->gcr_ptr;
gcr_track_start = gcr_data + ((current_halftrack >> 1) - 1) * GCR_TRACK_SIZE;
gcr_track_end = gcr_track_start + num_sectors[current_halftrack >> 1] * GCR_SECTOR_SIZE;
write_protected = state->write_protected;
disk_changed = state->disk_changed;
}