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disk.c
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/*
** Oricutron
** Copyright (C) 2009-2014 Peter Gordon
**
** This program 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, version 2
** of the License.
**
** This program 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 program; if not, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**
** WD17xx, Microdisc and Jasmin emulation
*/
/* The microdisc ROM has a bug where if no disk */
/* is inserted at boot, the disk detection routine */
/* has an unbalanced stack and there is a chance */
/* that it will end up executing garbage when you */
/* insert a disk. Euphoric has a fudge to work */
/* around this. It pretends a disk is in the drive */
/* but leaves the "read sector" command lingering */
/* until you insert a disk. Set this define to */
/* do the same fudge */
#define MICRODISC_FUDGE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "system.h"
#include "6502.h"
#include "via.h"
#include "8912.h"
#include "gui.h"
#include "disk.h"
#include "disk_pravetz.h"
#include "monitor.h"
#include "6551.h"
#include "machine.h"
#include "msgbox.h"
#include "filereq.h"
extern char diskfile[], diskpath[], filetmp[];
extern char telediskfile[], telediskpath[];
extern char pravdiskfile[], pravdiskpath[];
extern SDL_bool refreshdisks;
#define GENERAL_DISK_DEBUG 0
#define DEBUG_SECTOR_DUMP 0
#if DEBUG_SECTOR_DUMP
static char sectordumpstr[64];
static int sectordumpcount;
#endif
#ifdef MICRODISC_FUDGE
void microdisc_setintrq( void *md );
#endif
static Uint16 calc_crc( Uint16 crc, Uint8 value)
{
crc = ((unsigned char)(crc >> 8)) | (crc << 8);
crc ^= value;
crc ^= ((unsigned char)(crc & 0xff)) >> 4;
crc ^= (crc << 8) << 4;
crc ^= ((crc & 0xff) << 4) << 1;
return crc;
}
// Pop up disk image information for a couple of seconds
void disk_popup( struct machine *oric, int drive )
{
char tmp[40];
if( !oric->diskname[drive][0] )
{
do_popup( oric, "\x14\x15\x13" );
return;
}
sprintf( tmp, "\x14\x15""%d %-16s", drive, oric->diskname[drive] );
do_popup( oric, tmp );
}
// Free a disk image and clear the pointer to it
void diskimage_free( struct machine *oric, struct diskimage **dimg )
{
char *dpath, *dfile;
if( !(*dimg) ) return;
if( oric->type != MACH_TELESTRAT )
{
switch (oric->drivetype)
{
case DRV_PRAVETZ:
dpath = pravdiskpath;
dfile = pravdiskfile;
break;
default:
dpath = diskpath;
dfile = diskfile;
break;
}
} else {
dpath = telediskpath;
dfile = telediskfile;
}
if( (*dimg)->modified )
{
char modmsg[128];
sprintf( modmsg, "The disk in drive %d is modified.\nWould you like to save the changes?", (*dimg)->drivenum );
if( msgbox( oric, MSGBOX_YES_NO, modmsg ) )
{
sprintf( modmsg, "Save disk %d", (*dimg)->drivenum );
if( filerequester( oric, modmsg, dpath, dfile, FR_DISKSAVE ) )
{
joinpath( dpath, dfile );
diskimage_save( oric, filetmp, (*dimg)->drivenum );
}
}
}
if( (*dimg)->rawimage ) free( (*dimg)->rawimage );
free( *dimg );
(*dimg) = NULL;
}
// Read a raw integer from a disk image file
Uint32 diskimage_rawint( struct diskimage *dimg, Uint32 offset )
{
if( !dimg ) return 0;
if( ( !dimg->rawimage ) || ( dimg->rawimagelen < 4 ) ) return 0;
if( offset > (dimg->rawimagelen-4) ) return 0;
return (dimg->rawimage[offset+3]<<24)|(dimg->rawimage[offset+2]<<16)|(dimg->rawimage[offset+1]<<8)|dimg->rawimage[offset];
}
// Allocate and initialise a disk image structure
// If "rawimglen" isn't zero, it will also allocate
// ram for a raw disk image
struct diskimage *diskimage_alloc( Uint32 rawimglen )
{
struct diskimage *dimg;
Uint8 *buf=NULL;
if( rawimglen )
{
buf = malloc( rawimglen );
if( !buf ) return NULL;
}
dimg = malloc( sizeof( struct diskimage ) );
if( !dimg )
{
free( buf );
return NULL;
}
dimg->drivenum = -1;
dimg->numtracks = 0;
dimg->numsides = 0;
dimg->geometry = 0;
dimg->cachedtrack = -1;
dimg->cachedside = -1;
dimg->numsectors = 0;
dimg->rawimage = buf;
dimg->rawimagelen = rawimglen;
dimg->modified = SDL_FALSE;
dimg->modified_time = 0;
return dimg;
}
// Eject a disk from a drive
void disk_eject( struct machine *oric, int drive )
{
diskimage_free( oric, &oric->wddisk.disk[drive] );
oric->pravetz.drv[drive].pimg = NULL;
oric->pravetz.drv[drive].byte = 0;
oric->pravetz.drv[drive].dirty = SDL_FALSE;
oric->pravetz.drv[drive].half_track = 0;
oric->diskname[drive][0] = 0;
disk_popup( oric, drive );
}
// Whenever a seek operation occurs, the track where the head ends up
// is "cached". The track is located within the raw image file, and
// all the sector address and data markers are found, and pointers
// are remembered for each.
void diskimage_cachetrack( struct diskimage *dimg, int track, int side )
{
Uint8 *ptr, *eot;
Uint32 sectorcount, n;
// If this track is already cached, don't waste time doing it again
if( ( dimg->cachedtrack == track ) &&
( dimg->cachedside == side ) )
return;
// reset cached info
for( n=0; n<32; n++ )
{
dimg->sector[n].id_ptr = NULL;
dimg->sector[n].data_ptr = NULL;
}
dimg->numsectors = 0;
dimg->cachedtrack = -1;
dimg->cachedside = -1;
if( side >= dimg->numsides )
return;
// Find the start and end locations of the track within the disk image
ptr = &dimg->rawimage[(side*dimg->numtracks+track)*6400+256];
eot = &ptr[6400];
// Scan through the track looking for sectors
sectorcount = 0;
while( ptr < eot )
{
// Search for ID mark
while( (ptr<eot) && (ptr[0]!=0xfe) ) ptr++;
// Don't exceed the bounds of this track
if( ptr >= eot ) break;
// Store ID pointer
dimg->sector[sectorcount].id_ptr = ptr;
dimg->sector[sectorcount].data_ptr = NULL;
sectorcount++;
// Get N value
n = ptr[4];
// Skip ID field and CRC
ptr+=7;
// Search for data ID
while( (ptr<eot) && (ptr[0]!=0xfb) && (ptr[0]!=0xf8) ) ptr++;
if( ptr >= eot ) break;
// Store pointer
dimg->sector[sectorcount-1].data_ptr = ptr;
// Skip data field and ID
ptr += (1<<(n+7))+3;
}
if( 0 < sectorcount )
{
// Remember how many sectors we have successfully cached
dimg->numsectors = sectorcount;
dimg->cachedtrack = track;
dimg->cachedside = side;
}
}
// This saves a diskimage back to disk.
// Since the disk image is always kept in standard format, there is
// no processing of the image in this routine, it is just dumped from
// memory back to disk.
SDL_bool diskimage_save( struct machine *oric, char *fname, int drive )
{
FILE *f;
// Make sure there is a disk in the drive!
if( !oric->wddisk.disk[drive] ) return SDL_FALSE;
if( oric->drivetype == DRV_PRAVETZ )
disk_pravetz_write_image(&oric->pravetz.drv[drive]);
// Open the file for writing
f = fopen( fname, "wb" );
if( !f )
{
do_popup( oric, "\x14\x15Save failed" );
return SDL_FALSE;
}
// Dump it to disk
if( fwrite( oric->wddisk.disk[drive]->rawimage, oric->wddisk.disk[drive]->rawimagelen, 1, f ) != 1 )
{
fclose( f );
do_popup( oric, "\x14\x15Save failed" );
return SDL_FALSE;
}
// All done!
fclose( f );
// If we are not just overwriting the original file, remember the new filename
if( fname != oric->wddisk.disk[drive]->filename )
{
strncpy( oric->wddisk.disk[drive]->filename, fname, 4096+512 );
oric->wddisk.disk[drive]->filename[4096+511] = 0;
}
// The image in memory is no longer different to the last saved version
oric->wddisk.disk[drive]->modified = SDL_FALSE;
oric->wddisk.disk[drive]->modified_time = 0;
// Remember to update the GUI
refreshdisks = SDL_TRUE;
return SDL_TRUE;
}
// This routine "inserts" a disk image into a virtual drive
SDL_bool diskimage_load( struct machine *oric, char *fname, int drive )
{
FILE *f;
Uint32 len;
// Open the file
f = fopen( fname, "rb" );
if( !f ) return SDL_FALSE;
// The file exists, so eject any currently inserted disk
disk_eject( oric, drive );
// Determine the size of the disk image
fseek( f, 0, SEEK_END );
len = (int)ftell( f );
fseek( f, 0, SEEK_SET );
// Empty file!?
if( len <= 0 )
{
fclose( f );
return SDL_FALSE;
}
// Allocate a new disk image structure and space for the raw image
oric->wddisk.disk[drive] = diskimage_alloc( len );
if( !oric->wddisk.disk[drive] )
{
do_popup( oric, "\x14\x15""Out of memory" );
fclose( f );
return SDL_FALSE;
}
// Read the image file into memory
if( fread( oric->wddisk.disk[drive]->rawimage, len, 1, f ) != 1 )
{
fclose( f );
disk_eject( oric, drive );
do_popup( oric, "\x14\x15""Read error" );
return SDL_FALSE;
}
fclose( f );
if( oric->drivetype == DRV_PRAVETZ )
{
Uint16 t_idx;
Uint16 s_idx;
Uint16 sb_idx;
Uint16 tb_idx;
oric->pravetz.drv[drive].pimg = oric->wddisk.disk[drive];
if( drive >= 2 )
{
disk_eject( oric, drive );
do_popup( oric, "\x14\x15""Invalid drive number" );
return SDL_FALSE;
}
if( len != 143360 )
{
disk_eject( oric, drive );
do_popup( oric, "\x14\x15""Invalid pravetz disk image" );
return SDL_FALSE;
}
// Get some basic image info
for (t_idx = 0; t_idx < PRAV_TRACKS_PER_DISK; t_idx++)
{
tb_idx = 0;
for (s_idx = 0; s_idx < PRAV_SECTORS_PER_TRACK; s_idx++)
{
for (sb_idx = 0; sb_idx < PRAV_RAW_BYTES_PER_SECTOR; sb_idx++, tb_idx++)
{
oric->pravetz.drv[drive].image[t_idx][tb_idx] =
disk_pravetz_image_raw_byte(oric, drive, t_idx, s_idx, sb_idx);
}
}
while (tb_idx < PRAV_RAW_TRACK_SIZE)
{
oric->pravetz.drv[drive].image[t_idx][tb_idx] = 0xFF;
tb_idx++;
}
}
oric->pravetz.drv[drive].byte = 0;
oric->pravetz.drv[drive].half_track = 0;
}
else
{
// Check for the header ID
if( strncmp( (char *)oric->wddisk.disk[drive]->rawimage, "MFM_DISK", 8 ) != 0 )
{
disk_eject( oric, drive );
do_popup( oric, "\x14\x15""Invalid disk image" );
return SDL_FALSE;
}
// Get some basic image info
oric->wddisk.disk[drive]->drivenum = drive;
oric->wddisk.disk[drive]->numsides = diskimage_rawint( oric->wddisk.disk[drive], 8 );
oric->wddisk.disk[drive]->numtracks = diskimage_rawint( oric->wddisk.disk[drive], 12 );
oric->wddisk.disk[drive]->geometry = diskimage_rawint( oric->wddisk.disk[drive], 16 );
// Is the disk sane!?
if( ( oric->wddisk.disk[drive]->numsides < 1 ) ||
( oric->wddisk.disk[drive]->numsides > 2 ) )
{
disk_eject( oric, drive );
do_popup( oric, "\x14\x15""Invalid disk image" );
return SDL_FALSE;
}
}
// Nobody has written to this disk yet
oric->wddisk.disk[drive]->modified = SDL_FALSE;
oric->wddisk.disk[drive]->modified_time = 0;
// Remember the filename of the image for this drive
strncpy( oric->wddisk.disk[drive]->filename, fname, 4096+512 );
oric->wddisk.disk[drive]->filename[4096+511] = 0;
// Come up with a suitable short name for popups etc.
if( strlen( fname ) > 31 )
{
strncpy( oric->diskname[drive], &fname[strlen(fname)-31], 32 );
oric->diskname[drive][0] = 22;
} else {
strncpy( oric->diskname[drive], fname, 32 );
}
oric->diskname[drive][31] = 0;
// Do the popup
disk_popup( oric, drive );
// Mark the disk status icons as needing a refresh
refreshdisks = SDL_TRUE;
return SDL_TRUE;
};
// This routine does nothing. It is just used as a default for the callback routines
// and is usually replaced by the microdisc/jasmin/whatever implementations.
void wd17xx_dummy( void *nothing )
{
}
// Initialise a WD17xx controller instance
void wd17xx_init( struct wd17xx *wd )
{
wd->r_status = 0;
wd->r_track = 0;
wd->r_sector = 0;
wd->r_data = 0;
wd->c_drive = 0;
wd->c_side = 0;
wd->c_track = 0;
wd->c_sector = 0;
wd->last_step_in = SDL_FALSE;
wd->setintrq = wd17xx_dummy;
wd->clrintrq = wd17xx_dummy;
wd->intrqarg = NULL;
wd->setdrq = wd17xx_dummy;
wd->clrdrq = wd17xx_dummy;
wd->drqarg = NULL;
wd->currentop = COP_NUFFINK;
wd->delayedint = 0;
wd->delayeddrq = 0;
wd->distatus = -1;
wd->ddstatus = -1;
refreshdisks = SDL_TRUE;
}
// This routine emulates some cycles of disk activity.
void wd17xx_ticktock( struct wd17xx *wd, int cycles )
{
#ifdef MICRODISC_FUDGE
if ((wd->currentop == COP_READ_SECTORS_FUDGE) ||
(wd->currentop == COP_READ_SECTOR_FUDGE))
{
if (wd->disk[wd->c_drive])
{
wd->curroffs = 0;
wd->currsector = wd17xx_find_sector( wd, wd->r_sector );
if( !wd->currsector )
{
wd->r_status = WSF_RNF;
wd->clrdrq( wd->drqarg );
wd->setintrq( wd->intrqarg );
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: Sector %d not found.", wd->r_sector );
#endif
}
else
{
wd->currseclen = 1<<(wd->currsector->id_ptr[4]+7);
wd->r_status = WSF_BUSY|WSF_NOTREADY;
wd->delayeddrq = 60;
wd->currentop = (wd->currentop == COP_READ_SECTORS_FUDGE) ? COP_READ_SECTORS : COP_READ_SECTOR;
wd->crc = 0xe295;
refreshdisks = SDL_TRUE;
#if DEBUG_SECTOR_DUMP
sectordumpcount = 0;
sectordumpstr[0] = 0;
#endif
}
}
}
#endif
// Is there a pending INTRQ?
if( wd->delayedint > 0 )
{
// Count down the INTRQ timer!
wd->delayedint -= cycles;
// Time to assert INTRQ?
if( wd->delayedint <= 0 )
{
// Yep! Stop timing.
wd->delayedint = 0;
// Need to update the status register?
if( wd->distatus != -1 )
{
// Yep. Do so.
wd->r_status = wd->distatus;
wd->distatus = -1;
}
// Assert INTRQ (this function pointer is set up by the microdisc/jasmin/whatever controller)
wd->setintrq( wd->intrqarg );
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: Delayed INTRQ" );
#endif
}
}
// Is there a pending DRQ?
if( wd->delayeddrq > 0 )
{
// Count down the DRQ timer!
wd->delayeddrq -= cycles;
// Time to assert DRQ?
if( wd->delayeddrq <= 0 )
{
// Yep! Stop timing.
wd->delayeddrq = 0;
// Need to update the status register?
if( wd->ddstatus != -1 )
{
// Yep. Do so.
wd->r_status = wd->ddstatus;
wd->ddstatus = -1;
}
// Assert DRQ
wd->r_status |= WSF_DRQ;
wd->setdrq( wd->drqarg );
}
}
}
// This routine seeks to the specified track. It is used by the SEEK and STEP commands.
void wd17xx_seek_track( struct wd17xx *wd, Uint8 track, SDL_bool dofudge )
{
// Is there a disk in the drive?
if( wd->disk[wd->c_drive] )
{
// Yes. If we are trying to seek to a non-existant track, just seek as far as we can
if( track >= wd->disk[wd->c_drive]->numtracks )
{
track = (wd->disk[wd->c_drive]->numtracks>0)?wd->disk[wd->c_drive]->numtracks-1:0;
wd->distatus = WSFI_HEADL|WSFI_SEEKERR;
}
else
{
wd->distatus = WSFI_HEADL|WSFI_PULSE;
}
// Cache the new track
diskimage_cachetrack( wd->disk[wd->c_drive], track, wd->c_side );
// Update our status
wd->c_track = track;
wd->c_sector = 0;
wd->r_track = track;
// Assert INTRQ in 20 cycles time and update the status accordingly
// (note: 20 cycles is waaaaaay faster than any real drive could seek. The actual
// delay would depend how far the head had to seek, and what stepping speed was
// currently set).
wd->delayedint = 20;
if( wd->c_track == 0 ) wd->distatus |= WSFI_TRK0;
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: At track %u (%u sectors)", track, wd->disk[wd->c_drive]->numsectors );
#endif
return;
}
// No disk in drive
// Set INTRQ because the operation has finished.
wd->setintrq( wd->intrqarg );
wd->r_track = 0;
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: Seek fail" );
#endif
#ifdef MICRODISC_FUDGE
// Euphoric style workaround for the sedoric bug...
if ((dofudge) && (wd->setintrq == microdisc_setintrq))
{
wd->r_status = 0x44;
return;
}
#endif
// Set error state
wd->r_status = WSF_NOTREADY|WSFI_SEEKERR;
}
// This routine looks for the sector with the specified ID in the current track.
// It returns NULL if there is no such sector, or a structure with pointers to
// the ID and data fields if the sector is found.
struct mfmsector *wd17xx_find_sector( struct wd17xx *wd, Uint8 secid )
{
int revs=0;
struct diskimage *dimg;
// Save some typing...
dimg = wd->disk[wd->c_drive];
// No disk image? No sectors!
if( !dimg ) return NULL;
// Make sure the current track is cached
diskimage_cachetrack( dimg, wd->c_track, wd->c_side );
// No sectors on this track? Someone needs to format their disk...
if( dimg->numsectors < 1 )
return NULL;
// We do this more realistically than we need to since this is not
// a super-accurate emulation (for now). Never mind. Lets go
// around the track up to two times.
while( revs < 2 )
{
// Move on to the next sector
wd->c_sector = (wd->c_sector+1)%dimg->numsectors;
// If we passed through the start of the track, set the pulse bit in the status register
if( !wd->c_sector )
{
revs++;
wd->r_status |= WSFI_PULSE;
}
// Found the required sector?
if( dimg->sector[wd->c_sector].id_ptr[3] == secid )
return &dimg->sector[wd->c_sector];
}
// The search failed :-(
#if GENERAL_DISK_DEBUG
dbg_printf( "Couldn't find sector %u", secid );
#endif
return NULL;
}
// This returns the first valid sector in the current track, or NULL if
// there aren't any sectors.
struct mfmsector *wd17xx_first_sector( struct wd17xx *wd )
{
struct diskimage *dimg;
dimg = wd->disk[wd->c_drive];
// No disk? no sector...
if( !dimg ) return NULL;
// Make sure the current track is cached
diskimage_cachetrack( dimg, wd->c_track, wd->c_side );
// No sectors?!
if( dimg->numsectors < 1 )
return NULL;
// We're at the first sector!
wd->c_sector = 0;
wd->r_status = WSFI_PULSE;
// Return the sector pointers
return &dimg->sector[wd->c_sector];
}
// Move on to the next sector
struct mfmsector *wd17xx_next_sector( struct wd17xx *wd )
{
struct diskimage *dimg;
dimg = wd->disk[wd->c_drive];
// No disk? No sectors!
if( !dimg ) return NULL;
// Make sure the current track is cached
diskimage_cachetrack( dimg, wd->c_track, wd->c_side );
// No sectors?
if( dimg->numsectors < 1 )
return NULL;
// Get the next sector number
wd->c_sector = (wd->c_sector+1)%dimg->numsectors;
// If we are at the start of the track, set the pulse bit
if( !wd->c_sector ) wd->r_status |= WSFI_PULSE;
// Return the sector pointers
return &dimg->sector[wd->c_sector];
}
// Perform a read operation on a WD17xx register
unsigned char wd17xx_read( struct wd17xx *wd, unsigned short addr )
{
// Which register?!
switch( addr )
{
case 0: // Status register
wd->clrintrq( wd->intrqarg ); // Reading the status register clears INTRQ
return wd->r_status;
case 1: // Track register
return wd->r_track;
case 2: // Sector register
return wd->r_sector;
case 3: // Data register
// What are we currently doing?
switch( wd->currentop )
{
#ifdef MICRODISC_FUDGE
case COP_READ_SECTOR_FUDGE:
case COP_READ_SECTORS_FUDGE:
return 0;
#endif
case COP_READ_SECTOR:
case COP_READ_SECTORS:
// We somehow started a sector read operation without a valid sector.
if( !wd->currsector )
{
// Abort.
wd->r_status &= ~WSF_DRQ;
wd->r_status |= WSF_RNF;
wd->clrdrq( wd->drqarg );
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
break;
}
// If this is the first read of a read operation, remember the record type for later
if( wd->curroffs == 0 ) wd->sectype = (wd->currsector->data_ptr[wd->curroffs++]==0xf8)?WSFR_RECTYP:0x00;
// Get the next byte from the sector
wd->r_data = wd->currsector->data_ptr[wd->curroffs++];
wd->crc = calc_crc( wd->crc, wd->r_data );
// Clear any previous DRQ
wd->r_status &= ~WSF_DRQ;
wd->clrdrq( wd->drqarg );
#if DEBUG_SECTOR_DUMP
sprintf( §ordumpstr[sectordumpcount*2], "%02X", wd->r_data );
sectordumpstr[34+sectordumpcount] = ((wd->r_data>31)&&(wd->r_data<127)) ? wd->r_data : '.';
sectordumpcount++;
if( sectordumpcount >= 16 )
{
sectordumpstr[32] = ' ';
sectordumpstr[33] = '\'';
sectordumpstr[50] = '\'';
sectordumpstr[51] = 0;
dbg_printf( "%s", sectordumpstr );
sectordumpcount = 0;
}
#endif
// Has the whole sector been read?
if( wd->curroffs > wd->currseclen )
{
// If you want to do CRC checking, wd->crc should equal (wd->currsector->data_ptr[wd_curroffs]<<8)|wd->currsector->data_ptr[wd_curroffs+1] right here
#if DEBUG_SECTOR_DUMP
if( sectordumpcount )
{
sectordumpstr[33] = '\'';
sectordumpstr[34+sectordumpcount] = '\'';
sectordumpstr[35+sectordumpcount] = 0;
for( sectordumpcount*=2; sectordumpcount<33; sectordumpcount++ )
sectordumpstr[sectordumpcount*2] = ' ';
dbg_printf( "%s", sectordumpstr );
sectordumpcount = 0;
}
#endif
// We've got to the end of the current sector. IF it is a multiple sector
// operation, we need to move on!
if( wd->currentop == COP_READ_SECTORS )
{
#if GENERAL_DISK_DEBUG
dbg_printf( "Next sector..." );
#endif
// Get the next sector, and carry on!
wd->r_sector++;
wd->curroffs = 0;
wd->currsector = wd17xx_find_sector( wd, wd->r_sector );
wd->crc = 0xe295;
// If we hit the end of the track, thats fine, it just means the operation
// is finished.
if( !wd->currsector )
{
wd->delayedint = 20; // Assert INTRQ in 20 cycles time
wd->distatus = wd->sectype; // ...and when doing so, set the status to reflect the record type
wd->currentop = COP_NUFFINK; // No longer in the middle of an operation
wd->r_status &= (~WSF_DRQ); // Clear DRQ (no data to read)
wd->clrdrq( wd->drqarg );
refreshdisks = SDL_TRUE; // Turn off the disk LED in the status bar
break;
}
// We've got the next sector lined up. Assert DRQ in 180 cycles time (simulate a bit of a delay
// between sectors. Note that most of these values have been pulled out of thin air and might need
// adjusting for some pickier loaders).
wd->delayeddrq = 180;
break;
}
// Just reading one sector so..
wd->delayedint = 32; // INTRQ in a little while because we're finished
wd->distatus = wd->sectype; // Set the status accordingly
wd->currentop = COP_NUFFINK; // Finished the op
wd->r_status &= (~WSF_DRQ); // Clear DRQ (no more data)
wd->clrdrq( wd->drqarg );
refreshdisks = SDL_TRUE; // Turn off disk LED
} else {
wd->delayeddrq = 32; // More data ready. DRQ to let them know!
}
break;
case COP_READ_ADDRESS:
if( !wd->currsector )
{
wd->r_status &= ~WSF_DRQ;
wd->clrdrq( wd->drqarg );
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
break;
}
if( wd->curroffs == 0 ) wd->r_sector = wd->currsector->id_ptr[1];
wd->r_data = wd->currsector->id_ptr[++wd->curroffs];
wd->r_status &= ~WSF_DRQ;
wd->clrdrq( wd->drqarg );
if( wd->curroffs >= 6 )
{
wd->delayedint = 20;
wd->distatus = 0;
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
} else {
wd->delayeddrq = 32;
}
break;
}
return wd->r_data;
}
return 0; // ??
}
static SDL_bool last_step_in = SDL_FALSE;
void wd17xx_write( struct machine *oric, struct wd17xx *wd, unsigned short addr, unsigned char data )
{
switch( addr )
{
case 0: // Command register
wd->clrintrq( wd->intrqarg );
switch( data & 0xe0 )
{
case 0x00: // Restore or seek
switch( data & 0x10 )
{
case 0x00: // Restore (Type I)
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: (%04X) Restore", oric->cpu.pc-1 );
#endif
wd->r_status = WSF_BUSY;
if( data & 8 ) wd->r_status |= WSFI_HEADL;
wd17xx_seek_track( wd, 0, oric->cpu.calcpc == 0xe3a1 );
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
break;
case 0x10: // Seek (Type I)
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: (%04X) Seek", oric->cpu.pc-1 );
#endif
wd->r_status = WSF_BUSY;
if( data & 8 ) wd->r_status |= WSFI_HEADL;
wd17xx_seek_track( wd, wd->r_data, SDL_FALSE );
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
break;
}
break;
case 0x20: // Step (Type I)
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: (%04X) Step", oric->cpu.pc-1 );
#endif
wd->r_status = WSF_BUSY;
if( data & 8 ) wd->r_status |= WSFI_HEADL;
if( last_step_in )
wd17xx_seek_track( wd, wd->c_track+1, SDL_FALSE );
else
wd17xx_seek_track( wd, wd->c_track > 0 ? wd->c_track-1 : 0, SDL_FALSE );
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
break;
case 0x40: // Step-in (Type I)
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: (%04X) Step-In (%d,%d)", oric->cpu.pc-1, wd->c_track, wd->c_track+1 );
#endif
wd->r_status = WSF_BUSY;
if( data & 8 ) wd->r_status |= WSFI_HEADL;
wd17xx_seek_track( wd, wd->c_track+1, SDL_FALSE );
last_step_in = SDL_TRUE;
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
break;
case 0x60: // Step-out (Type I)
#if GENERAL_DISK_DEBUG
dbg_printf( "DISK: Step-Out" );
#endif
wd->r_status = WSF_BUSY;
if( data & 8 ) wd->r_status |= WSFI_HEADL;
if( wd->c_track > 0 )
wd17xx_seek_track( wd, wd->c_track-1, SDL_FALSE );
last_step_in = SDL_FALSE;
wd->currentop = COP_NUFFINK;
refreshdisks = SDL_TRUE;
break;
case 0x80: // Read sector (Type II)
#if GENERAL_DISK_DEBUG
switch( oric->drivetype )
{
case DRV_MICRODISC:
dbg_printf( "DISK: (%04X) Read sector %u (CODE=%02X,ROM=%s,EPROM=%s)", oric->cpu.pc-1, wd->r_sector, data, oric->romdis?"OFF":"ON", oric->md.diskrom?"ON":"OFF" );
break;
default:
dbg_printf( "DISK: (%04X) Read sector %u (CODE=%02X)", oric->cpu.pc-1, wd->r_sector, data );
break;
}
#endif
#ifdef MICRODISC_FUDGE
if (!wd->disk[wd->c_drive])
{
wd->currentop = (data&0x10) ? COP_READ_SECTORS_FUDGE : COP_READ_SECTOR_FUDGE;
break;
}
#endif
wd->curroffs = 0;