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Mac Magazin/MacEasy 19
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Mac Magazin and MacEasy Magazine CD - Issue 19.iso
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Utilities
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uae-0.4
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Source Code
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disk.c
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1996-02-05
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448 lines
/*
* UAE - The Un*x Amiga Emulator
*
* Floppy disk emulation
*
* (c) 1995 Bernd Schmidt, Hannu Rummukainen
*/
#include <string.h>
#include <stdio.h>
#include "config.h"
#include "amiga.h"
#include "options.h"
#include "memory.h"
#include "ersatz.h"
#include "disk.h"
int indexpulse = 0;
UWORD* mfmwrite;
static UWORD mfmwrbuffer[16384]; /* space for maximum disk DMA transfer */
static int side, direction, step;
static UBYTE selected = 15;
static bool dskready;
static bool need_read = false;
typedef struct {
UWORD sync;
UWORD len;
ULONG offs;
} trackid;
typedef enum { ADF_NORMAL, ADF_EXT1 } drive_filetype;
typedef struct {
FILE *diskfile;
drive_filetype filetype;
trackid trackdata[164];
unsigned int track;
bool motoroff;
bool wrprot;
unsigned int trackoffs,insecpos;
bool secok;
UBYTE secbuf[544];
UWORD mfmbuf[544];
} drive;
drive floppy[4];
static void drive_insert(drive *drv, char *fname)
{
unsigned char buffer[10];
drv->diskfile = fopen(fname,"r+b");
if (drv->diskfile) {
drv->wrprot = false;
} else {
drv->wrprot = true;
drv->diskfile = fopen(fname, "rb");
if (!drv->diskfile) return;
}
fread(buffer,sizeof(char),8,drv->diskfile);
if (strncmp((char *)buffer,"UAE--ADF",8) == 0) {
int offs = 160*4+8;
int i;
drv->filetype = ADF_EXT1;
drv->wrprot = true; /* write to adf_ext1 not implemented */
for(i=0; i<160; i++) {
fread(buffer, 4, 1, drv->diskfile);
drv->trackdata[i].sync = buffer[0]*256 + buffer[1];
drv->trackdata[i].len = buffer[2]*256 + buffer[3];
drv->trackdata[i].offs = offs;
offs += drv->trackdata[i].len;
}
} else {
int i;
drv->filetype = ADF_NORMAL;
for(i=0; i<160; i++) {
drv->trackdata[i].len = 512 * 11;
drv->trackdata[i].sync = 0;
drv->trackdata[i].offs = i*512*11;
}
}
}
static void drive_step(drive *drv)
{
if (direction) {
if (drv->track) drv->track--;
} else {
if (drv->track < 85) drv->track++;
}
}
static bool drive_track0(drive *drv)
{
return drv->track == 0;
}
static bool drive_writeprotected(drive *drv)
{
return drv->wrprot || drv->diskfile == NULL;
}
static bool drive_empty(drive *drv)
{
return drv->diskfile == 0;
}
static bool drive_running(drive *drv)
{
return !drv->motoroff;
}
static void drive_index(drive *drv)
{
drv->trackoffs = 0;
drv->insecpos = 0;
}
static void drive_motor(drive *drv, bool off)
{
if (drv->motoroff && !off) {
drv->trackoffs = 0;
drv->insecpos = 0;
drv->secok = false;
}
drv->motoroff = off;
}
static ULONG drive_getmfmulong(drive *drv, unsigned int offs)
{
return (drv->mfmbuf[offs] << 16) | drv->mfmbuf[offs+1];
}
static ULONG drive_getseculong(drive *drv, unsigned int offs)
{
return ((drv->secbuf[offs] << 24) | (drv->secbuf[offs+1] << 16)
| (drv->secbuf[offs+2] << 8) | (drv->secbuf[offs+3]));
}
static void drive_readsec(drive *drv)
{
ULONG deven,dodd;
ULONG hck=0,dck=0;
int i;
if (!drv->diskfile) return;
drv->secbuf[0] = drv->secbuf[1] = 0x00;
drv->secbuf[2] = drv->secbuf[3] = 0xa1;
drv->secbuf[4] = 0xff;
drv->secbuf[5] = drv->track*2 + side;
drv->secbuf[6] = drv->trackoffs;
drv->secbuf[7] = 11-drv->trackoffs;
for(i = 8; i < 24; i++)
drv->secbuf[i] = 0;
fseek(drv->diskfile,
drv->trackdata[drv->track*2 + side].offs + drv->trackoffs*512,
SEEK_SET);
fread(&drv->secbuf[32],sizeof(UBYTE),512,drv->diskfile);
drv->mfmbuf[0] = drv->mfmbuf[1] = 0xaaaa;
drv->mfmbuf[2] = drv->mfmbuf[3] = 0x4489;
deven = drive_getseculong(drv, 4); dodd = deven >> 1;
deven &= 0x55555555; dodd &= 0x55555555;
drv->mfmbuf[4] = dodd >> 16;
drv->mfmbuf[5] = dodd;
drv->mfmbuf[6] = deven>> 16;
drv->mfmbuf[7] = deven;
for (i = 8; i < 48; i++)
drv->mfmbuf[i] = 0;
for (i = 0; i < 512; i += 4){
deven = drive_getseculong(drv, i + 32);
dodd = deven >> 1;
deven &= 0x55555555; dodd &= 0x55555555;
drv->mfmbuf[(i>>1)+32] = dodd >> 16;
drv->mfmbuf[(i>>1)+33] = dodd;
drv->mfmbuf[(i>>1)+256+32] = deven>> 16;
drv->mfmbuf[(i>>1)+256+33] = deven;
}
for(i = 4; i < 24; i += 2)
hck ^= drive_getmfmulong(drv, i);
deven = dodd = hck; dodd >>= 1;
drv->mfmbuf[24] = dodd >> 16; drv->mfmbuf[25] = dodd;
drv->mfmbuf[26] = deven>> 16; drv->mfmbuf[27] = deven;
for(i = 32; i < 544; i += 2)
dck ^= drive_getmfmulong(drv, i);
deven = dodd = dck; dodd >>= 1;
drv->mfmbuf[28] = dodd >> 16; drv->mfmbuf[29] = dodd;
drv->mfmbuf[30] = deven>> 16; drv->mfmbuf[31] = deven;
drv->secok = true;
need_read = false;
drv->insecpos = 0;
}
static void drive_get_data(drive *drv, UWORD *mfm, UWORD *byt)
{
if (drv->trackdata[drv->track*2 + side].sync == 0) {
/* Normal AmigaDOS format track */
if (!drv->secok || need_read)
drive_readsec(drv);
*mfm = drv->mfmbuf[drv->insecpos];
*byt = drv->secbuf[drv->insecpos++];
if (drv->insecpos == 544){
drv->insecpos = 0;
drv->secok = false;
if (++drv->trackoffs == 11)
drv->trackoffs = 0;
}
} else {
/* Raw MFM track */
if (drv->insecpos > drv->trackdata[drv->track*2+side].len)
drv->insecpos = 0;
if (drv->insecpos == 0) {
*mfm = drv->trackdata[drv->track*2 + side].sync;
} else {
unsigned char data[2];
fseek(drv->diskfile,
drv->insecpos*2 - 2 + drv->trackdata[drv->track*2+side].offs,
SEEK_SET);
fread(data, 2, 1, drv->diskfile);
*mfm = data[0]*256 + data[1];
/* ??? how does this work? */
*byt = (data[0] & 0x55) | ((data[1] & 0x55)*2);
}
drv->insecpos++;
}
}
#define MFMMASK 0x55555555
static __inline__ ULONG getmfmlong(UWORD* mbuf)
{
return ((*mbuf << 16) | *(mbuf + 1)) & MFMMASK;
}
static void drive_write_data(drive *drv, UWORD *mbuf, UWORD *mend)
{
int i, secwritten = 0;
ULONG odd, even, chksum, id, dlong;
UBYTE* secdata;
if (drive_writeprotected(drv)) return;
mend -= (4 + 16 + 8 + 512);
while (mbuf < mend) {
do {
while (*mbuf++ != 0x4489) {
if (mbuf >= mend) return;
}
} while (*mbuf++ != 0x4489);
odd = getmfmlong(mbuf);
even = getmfmlong(mbuf+2);
mbuf += 4;
id = (odd << 1) | even;
drv->trackoffs = (id & 0xff00) >> 8;
if (drv->trackoffs > 10) {
printf("Disk write: weird sector number %d\n", drv->trackoffs);
continue;
}
chksum = odd ^ even;
for (i=0; i<4; i++) {
odd = getmfmlong(mbuf);
even = getmfmlong(mbuf+8);
mbuf += 2;
dlong = (odd << 1) | even;
if (dlong) secwritten = -200;
chksum ^= odd ^ even;
} /* could check here if the label is nonstandard */
mbuf += 8;
odd = getmfmlong(mbuf); even = getmfmlong(mbuf+2); mbuf += 4;
if ((((odd << 1) | even) != chksum) ||
(((id & 0x00ff0000) >> 16) != drv->track*2 + side)) {
printf("Disk write: checksum error on sector header\n");
continue;
}
odd = getmfmlong(mbuf); even = getmfmlong(mbuf+2); mbuf += 4;
chksum = (odd << 1) | even;
secdata = drv->secbuf + 32;
for (i=0; i<128; i++) {
odd = getmfmlong(mbuf); even = getmfmlong(mbuf+256); mbuf += 2;
dlong = (odd << 1) | even;
*secdata++ = dlong >> 24; *secdata++ = (dlong >> 16) & 0xff;
*secdata++ = dlong >> 8; *secdata++ = dlong;
chksum ^= odd ^ even;
}
mbuf += 256;
if (chksum) {
printf("Disk write: data checksum error\n");
continue;
}
secwritten++;
fseek(drv->diskfile,
drv->trackdata[drv->track*2 + side].offs + drv->trackoffs*512,
SEEK_SET);
fwrite(drv->secbuf+32, sizeof(UBYTE), 512, drv->diskfile);
}
if (++drv->trackoffs == 11) drv->trackoffs = 0;
drv->insecpos = 0;
drv->secok = false;
if (secwritten == 0)
printf("Disk write in unsupported format\n");
if (secwritten < 0)
printf("Disk write: sector labels ignored\n");
}
static void drive_init(drive *drv, char *fname)
{
drv->diskfile = 0;
if (fname != 0) drive_insert(drv, fname);
drv->track = 0;
drv->motoroff = true;
}
static void drive_eject(drive *drv)
{
if (!drive_empty(drv)) fclose(drv->diskfile);
drv->diskfile = 0;
}
/* We use this function if we have no Kickstart ROM. */
void DISK_ersatz_read (int tr, int sec, CPTR dest)
{
int i;
floppy[0].trackoffs = sec;
floppy[0].insecpos = 0;
side = tr & 1;
floppy[0].track = tr >> 1;
drive_readsec(floppy);
for (i = 0; i < 512; i++) {
put_byte (dest + i, floppy[0].secbuf[32+i]);
}
}
void DISK_init()
{
drive_insert(floppy, "df0.adf");
drive_insert(floppy + 1, "df1.adf");
drive_insert(floppy + 2, "df2.adf");
drive_insert(floppy + 3, "df3.adf");
}
void DISK_Index()
{
int i;
for(i=0; i<4; i++) {
drive_index(floppy + i);
}
}
void DISK_select(UBYTE data)
{
int step_pulse;
int dr;
if (selected != ((data >> 3) & 15)) dskready = false;
selected = (data >> 3) & 15;
if (side != 1 - ((data >> 2) & 1)) {
side = 1 - ((data >> 2) & 1);
need_read = true;
}
direction = (data >> 1) & 1;
step_pulse = data & 1;
if (step != step_pulse) {
step = step_pulse;
if (step == 0){
for (dr = 0; dr < 4; dr++){
if (!(selected & (1 << dr))) {
drive_step(floppy + dr);
}
}
}
}
for (dr = 0; dr < 4; dr++){
if (!(selected & (1<<dr))) {
drive_motor(floppy + dr, data >> 7);
}
}
}
UBYTE DISK_status()
{
UBYTE st = 0x3c;
int dr;
for (dr = 0; dr < 4; dr++){
if (!(selected & (1 << dr))) {
if (drive_running(floppy + dr)){
if (dskready) st &= ~0x20;
dskready = true;
} else {
st &= ~0x20; /* report drive ID */
}
if (drive_track0(floppy + dr)) { st &= ~0x10; }
if (drive_writeprotected(floppy + dr)) { st &= ~8; }
if (drive_empty(floppy + dr)) { st &= ~0x4; }
}
}
return st;
}
void DISK_GetData(UWORD *mfm,UWORD *byt)
{
int dr;
for (dr = 0; dr < 4; dr++){
if (!(selected & (1<<dr))) {
drive_get_data (floppy + dr, mfm, byt);
}
}
}
void DISK_InitWrite()
{
mfmwrite = mfmwrbuffer;
}
void DISK_WriteData()
{
int dr;
for (dr=0;dr<4;dr++){
if (!(selected & (1<<dr))) {
drive_write_data(floppy + dr, mfmwrbuffer, mfmwrite);
}
}
}