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Code fixed to operate correctly.

This commit is contained in:
Michael Brown 2005-04-18 15:48:20 +00:00
parent 400fd74897
commit 7af89ccf33
1 changed files with 26 additions and 23 deletions
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49
src/arch/i386/drivers/bus/bios_disks.c
View File

@ -2,10 +2,16 @@
#define CF ( 1 << 0 )
/**************************************************************************
DISK_INIT - Initialize the disk system
**************************************************************************/
void disk_init ( void ) {
struct disk_sector {
char data[512];
};
/*
* Reset the disk system using INT 13,0. Forces both hard disks and
* floppy disks to seek back to track 0.
*
*/
static void disk_init ( void ) {
REAL_EXEC ( rm_disk_init,
"sti\n\t"
"xorw %%ax,%%ax\n\t"
@ -19,38 +25,35 @@ void disk_init ( void ) {
"ebp", "esi", "edi" ) );
}
/**************************************************************************
DISK_READ - Read a sector from disk
**************************************************************************/
unsigned int pcbios_disk_read ( int drive, int cylinder, int head, int sector,
char *fixme_buf ) {
uint16_t ax, flags, discard_c, discard_d;
segoff_t buf = SEGOFF ( fixme_buf );
/* FIXME: buf should be passed in as a segoff_t rather than a
* char *
*/
/*
* Read a single sector from a disk using INT 13,2.
*
* Returns the BIOS status code (%ah) - 0 indicates success
*
*/
static unsigned int pcbios_disk_read ( int drive, int cylinder, int head,
int sector, struct disk_sector *buf ) {
uint16_t basemem_buf, status, flags;
int discard_c, discard_d;
basemem_buf = BASEMEM_PARAMETER_INIT ( *buf );
REAL_EXEC ( rm_pcbios_disk_read,
"sti\n\t"
"pushl %%ebx\n\t" /* Convert %ebx to %es:bx */
"popw %%bx\n\t"
"popw %%es\n\t"
"movb $0x02, %%ah\n\t" /* INT 13,2 - Read disk sector */
"movb $0x01, %%al\n\t" /* Read one sector */
"movw $0x0201, %%ax\n\t" /* Read a single sector */
"int $0x13\n\t"
"pushfw\n\t"
"popw %%bx\n\t"
"cli\n\t",
4,
OUT_CONSTRAINTS ( "=a" ( ax ), "=b" ( flags ),
OUT_CONSTRAINTS ( "=a" ( status ), "=b" ( flags ),
"=c" ( discard_c ), "=d" ( discard_d ) ),
IN_CONSTRAINTS ( "c" ( ( ( cylinder & 0xff ) << 8 ) |
( ( cylinder >> 8 ) & 0x3 ) |
sector ),
"d" ( ( head << 8 ) | drive ),
"b" ( buf ) ),
"b" ( basemem_buf ) ),
CLOBBER ( "ebp", "esi", "edi" ) );
BASEMEM_PARAMETER_DONE ( *buf );
return ( flags & CF ) ? ax : 0;
return ( flags & CF ) ? ( status >> 8 ) : 0;
}