// INT 13h Fixed Disk Services Entry Point
void VISIBLE16
handle_13(struct bregs *regs)
{
debug_enter(regs, DEBUG_HDL_13);
u8 extdrive = regs->dl;
if (CONFIG_CDROM_EMU) {
if (regs->ah == 0x4b) {
cdemu_134b(regs);
return;
}
u16 ebda_seg = get_ebda_seg();
if (GET_EBDA2(ebda_seg, cdemu.active)) {
u8 emudrive = GET_EBDA2(ebda_seg, cdemu.emulated_extdrive);
if (extdrive == emudrive) {
// Access to an emulated drive.
struct drive_s *cdemu = GET_GLOBAL(cdemu_drive);
if (regs->ah > 0x16) {
// Only old-style commands supported.
disk_13XX(regs, cdemu);
return;
}
disk_13(regs, cdemu);
return;
}
if (extdrive < EXTSTART_CD && ((emudrive ^ extdrive) & 0x80) == 0)
// Adjust id to make room for emulated drive.
extdrive--;
}
}
handle_legacy_disk(regs, extdrive);
}
// 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;
}
static void
fillLCHS(struct drive_s *drive_g, u16 *nlc, u16 *nlh, u16 *nlspt)
{
if (CONFIG_CDROM_EMU && drive_g == GET_GLOBAL(cdemu_drive)) {
// 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);
}
// lock
static void
disk_134500(struct bregs *regs, struct drive_s *drive_g)
{
u16 ebda_seg = get_ebda_seg();
int cdid = regs->dl - EXTSTART_CD;
u8 locks = GET_EBDA2(ebda_seg, cdrom_locks[cdid]);
if (locks == 0xff) {
regs->al = 1;
disk_ret(regs, DISK_RET_ETOOMANYLOCKS);
return;
}
SET_EBDA2(ebda_seg, cdrom_locks[cdid], locks + 1);
regs->al = 1;
disk_ret(regs, DISK_RET_SUCCESS);
}
// unlock
static void
disk_134501(struct bregs *regs, struct drive_s *drive_g)
{
u16 ebda_seg = get_ebda_seg();
int cdid = regs->dl - EXTSTART_CD;
u8 locks = GET_EBDA2(ebda_seg, cdrom_locks[cdid]);
if (locks == 0x00) {
regs->al = 0;
disk_ret(regs, DISK_RET_ENOTLOCKED);
return;
}
locks--;
SET_EBDA2(ebda_seg, cdrom_locks[cdid], locks);
regs->al = (locks ? 1 : 0);
disk_ret(regs, DISK_RET_SUCCESS);
}