static int
cdemu_read(struct disk_op_s *op)
{
struct drive_s *drive_g;
drive_g = GLOBALFLAT2GLOBAL(GET_LOW(CDEmu.emulated_drive_gf));
struct disk_op_s dop;
dop.drive_g = drive_g;
dop.command = op->command;
dop.lba = GET_LOW(CDEmu.ilba) + op->lba / 4;
int count = op->count;
op->count = 0;
u8 *cdbuf_fl = GET_GLOBAL(bounce_buf_fl);
if (op->lba & 3) {
// Partial read of first block.
dop.count = 1;
dop.buf_fl = cdbuf_fl;
int ret = process_op(&dop);
if (ret)
return ret;
u8 thiscount = 4 - (op->lba & 3);
if (thiscount > count)
thiscount = count;
count -= thiscount;
memcpy_fl(op->buf_fl, cdbuf_fl + (op->lba & 3) * 512, thiscount * 512);
op->buf_fl += thiscount * 512;
op->count += thiscount;
dop.lba++;
}
if (count > 3) {
// Read n number of regular blocks.
dop.count = count / 4;
dop.buf_fl = op->buf_fl;
int ret = process_op(&dop);
op->count += dop.count * 4;
if (ret)
return ret;
u8 thiscount = count & ~3;
count &= 3;
op->buf_fl += thiscount * 512;
dop.lba += thiscount / 4;
}
if (count) {
// Partial read on last block.
dop.count = 1;
dop.buf_fl = cdbuf_fl;
int ret = process_op(&dop);
if (ret)
return ret;
u8 thiscount = count;
memcpy_fl(op->buf_fl, cdbuf_fl, thiscount * 512);
op->count += thiscount;
}
return DISK_RET_SUCCESS;
}
struct drive_s *
getDrive(u8 exttype, u8 extdriveoffset)
{
if (extdriveoffset >= ARRAY_SIZE(IDMap[0]))
return NULL;
struct drive_s *drive_gf = GET_GLOBAL(IDMap[exttype][extdriveoffset]);
if (!drive_gf)
return NULL;
return GLOBALFLAT2GLOBAL(drive_gf);
}
// read disk drive parameters
static void noinline
disk_1308(struct bregs *regs, struct drive_s *drive_g)
{
u16 ebda_seg = get_ebda_seg();
// Get logical geometry from table
u16 nlc, nlh, nlspt;
fillLCHS(drive_g, &nlc, &nlh, &nlspt);
nlc--;
nlh--;
u8 count;
if (regs->dl < EXTSTART_HD) {
// Floppy
count = GET_GLOBAL(FloppyCount);
if (CONFIG_CDROM_EMU
&& drive_g == GLOBALFLAT2GLOBAL(GET_GLOBAL(cdemu_drive_gf)))
regs->bx = GET_EBDA2(ebda_seg, cdemu.media) * 2;
else
regs->bx = GET_GLOBAL(drive_g->floppy_type);
// set es & di to point to 11 byte diskette param table in ROM
regs->es = SEG_BIOS;
regs->di = (u32)&diskette_param_table2;
} else if (regs->dl < EXTSTART_CD) {
// Hard drive
count = GET_BDA(hdcount);
nlc--; // last sector reserved
} else {
// Not supported on CDROM
disk_ret(regs, DISK_RET_EPARAM);
return;
}
if (CONFIG_CDROM_EMU && GET_EBDA2(ebda_seg, cdemu.active)) {
u8 emudrive = GET_EBDA2(ebda_seg, cdemu.emulated_extdrive);
if (((emudrive ^ regs->dl) & 0x80) == 0)
// Note extra drive due to emulation.
count++;
if (regs->dl < EXTSTART_HD && count > 2)
// Max of two floppy drives.
count = 2;
}
regs->al = 0;
regs->ch = nlc & 0xff;
regs->cl = ((nlc >> 2) & 0xc0) | (nlspt & 0x3f);
regs->dh = nlh;
disk_ret(regs, DISK_RET_SUCCESS);
regs->dl = count;
}
// Get the cylinders/heads/sectors for the given drive.
static void
fillLCHS(struct drive_s *drive_g, u16 *nlc, u16 *nlh, u16 *nlspt)
{
if (CONFIG_CDROM_EMU
&& drive_g == GLOBALFLAT2GLOBAL(GET_GLOBAL(cdemu_drive_gf))) {
// Emulated drive - get info from ebda. (It's not possible to
// populate the geometry directly in the driveid because the
// geometry is only known after the bios segment is made
// read-only).
u16 ebda_seg = get_ebda_seg();
*nlc = GET_EBDA2(ebda_seg, cdemu.lchs.cylinders);
*nlh = GET_EBDA2(ebda_seg, cdemu.lchs.heads);
*nlspt = GET_EBDA2(ebda_seg, cdemu.lchs.spt);
return;
}
*nlc = GET_GLOBAL(drive_g->lchs.cylinders);
*nlh = GET_GLOBAL(drive_g->lchs.heads);
*nlspt = GET_GLOBAL(drive_g->lchs.spt);
}
// Get the cylinders/heads/sectors for the given drive.
static struct chs_s
getLCHS(struct drive_s *drive_g)
{
struct chs_s res = { };
if (CONFIG_CDROM_EMU
&& drive_g == GLOBALFLAT2GLOBAL(GET_GLOBAL(cdemu_drive_gf))) {
// Emulated drive - get info from CDEmu. (It's not possible to
// populate the geometry directly in the driveid because the
// geometry is only known after the bios segment is made
// read-only).
res.cylinders = GET_LOW(CDEmu.lchs.cylinders);
res.heads = GET_LOW(CDEmu.lchs.heads);
res.spt = GET_LOW(CDEmu.lchs.spt);
return res;
}
res.cylinders = GET_GLOBAL(drive_g->lchs.cylinders);
res.heads = GET_GLOBAL(drive_g->lchs.heads);
res.spt = GET_GLOBAL(drive_g->lchs.spt);
return res;
}