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Change %dl fixup rules for INT13:

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INT 13,08 : read number of drives from 40:75
INT 13,15 : do nothing
all others : restore original value of %dl
This commit is contained in:
Michael Brown 2007-07-09 20:37:39 +01:00
parent c7d9fdb5b9
commit b90d321dfb
1 changed files with 16 additions and 11 deletions
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27
src/arch/i386/interface/pcbios/int13.c
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@ -466,23 +466,28 @@ static void hook_int13 ( void ) {
/* 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"
/* Fix up %dl:
*
* INT 13,15 : do nothing
* INT 13,08 : load with number of drives
* all others: restore original value
*/
"cmpb $0x15, -1(%%bp)\n\t"
"je 2f\n\t"
"movb -4(%%bp), %%dl\n\t"
"\n2:\n\t"
"cmpb $0x08, -1(%%bp)\n\t"
"jne 2f\n\t"
"pushw %%ds\n\t"
"pushw %1\n\t"
"popw %%ds\n\t"
"movb %c2, %%dl\n\t"
"popw %%ds\n\t"
/* Return */
"\n2:\n\t"
"movw %%bp, %%sp\n\t"
"popw %%bp\n\t"
"iret\n\t" ) : : "i" ( int13 ) );
"iret\n\t" )
: : "i" ( int13 ), "i" ( BDA_SEG ), "i" ( BDA_NUM_DRIVES ) );
hook_bios_interrupt ( 0x13, ( unsigned int ) int13_wrapper,
&int13_vector );