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Proof of concept; works, but has several hard-coded hacks.

This commit is contained in:
Michael Brown 2007-07-09 20:28:40 +01:00
parent 8bce52d348
commit c7d9fdb5b9
1 changed files with 46 additions and 7 deletions
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53
src/arch/i386/interface/pcbios/int13.c
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@ -355,12 +355,18 @@ static int int13_cdrom_status_terminate ( struct int13_drive *drive,
*/
static void int13 ( struct i386_all_regs *ix86 ) {
int command = ix86->regs.ah;
unsigned int bios_drive = ix86->regs.dl;
unsigned int original_bios_drive = bios_drive;
struct int13_drive *drive;
int status;
list_for_each_entry ( drive, &drives, list ) {
if ( drive->drive != ix86->regs.dl )
if ( drive->drive > bios_drive )
continue;
if ( drive->drive < bios_drive ) {
original_bios_drive--;
continue;
}
DBG ( "INT 13,%04x (%02x): ", ix86->regs.ax, drive->drive );
@ -421,6 +427,13 @@ static void int13 ( struct i386_all_regs *ix86 ) {
break;
}
/* Remap BIOS drive */
if ( bios_drive != original_bios_drive ) {
DBG ( "INT 13,%04x (%02x) remapped to (%02x)\n",
ix86->regs.ax, bios_drive, original_bios_drive );
}
ix86->regs.dl = original_bios_drive;
}
/**
@ -434,19 +447,42 @@ static void hook_int13 ( void ) {
*/
__asm__ __volatile__ (
TEXT16_CODE ( "\nint13_wrapper:\n\t"
"orb $0, %%al\n\t" /* clear OF */
/* Preserve %ax and %dx for future reference */
"pushw %%bp\n\t"
"movw %%sp, %%bp\n\t"
"pushw %%ax\n\t"
"pushw %%dx\n\t"
/* Clear OF, set CF, call int13() */
"orb $0, %%al\n\t"
"stc\n\t"
"pushl %0\n\t" /* call int13() */
"pushl %0\n\t"
"pushw %%cs\n\t"
"call prot_call\n\t"
"jo 1f\n\t" /* chain if OF not set */
/* Chain if OF not set */
"jo 1f\n\t"
"pushfw\n\t"
"lcall *%%cs:int13_vector\n\t"
"\n1:\n\t"
"call 2f\n\t" /* return with flags intact */
"lret $2\n\t"
/* Overwrite flags for iret */
"pushfw\n\t"
"popw 6(%%bp)\n\t"
/* Restore %dl (except for %ah=0x08 or 0x15) */
"cmpb $0x08, -1(%%bp)\n\t"
"jne 7f\n\t"
"movb $2, %%dl\n\t"
"jmp 2f\n\t"
"\n7:\n\t"
"je 2f\n\t"
"cmpb $0x15, -1(%%bp)\n\t"
"je 2f\n\t"
"movb -4(%%bp), %%dl\n\t"
"\n2:\n\t"
"ret $4\n\t" ) : : "i" ( int13 ) );
/* Return */
"movw %%bp, %%sp\n\t"
"popw %%bp\n\t"
"iret\n\t" ) : : "i" ( int13 ) );
hook_bios_interrupt ( 0x13, ( unsigned int ) int13_wrapper,
&int13_vector );
@ -541,6 +577,9 @@ void register_int13_drive ( struct int13_drive *drive ) {
drive->drive = ( num_drives | 0x80 );
if ( num_drives <= ( drive->drive & 0x7f ) )
num_drives = ( ( drive->drive & 0x7f ) + 1 );
num_drives = 2;
put_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES );
DBG ( "Registered INT13 drive %02x with C/H/S geometry %d/%d/%d\n",