Extracted from firmware/pcbios/bios.c

diff --git a/src/arch/i386/drivers/bus/bios_disks.c b/src/arch/i386/drivers/bus/bios_disks.c
new file mode 100644 (file)
index 0000000..d765111
--- /dev/null
+++ b/src/arch/i386/drivers/bus/bios_disks.c
@@ -0,0 +1,56 @@
+#include "realmode.h"
+
+#define CF ( 1 << 0 )
+
+/**************************************************************************
+DISK_INIT - Initialize the disk system
+**************************************************************************/
+void disk_init ( void ) {
+       REAL_EXEC ( rm_disk_init,
+                   "sti\n\t"
+                   "xorw %%ax,%%ax\n\t"
+                   "movb $0x80,%%dl\n\t"
+                   "int $0x13\n\t"
+                   "cli\n\t",
+                   0,
+                   OUT_CONSTRAINTS (),
+                   IN_CONSTRAINTS (),
+                   CLOBBER ( "eax", "ebx", "ecx", "edx",
+                             "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 *
+        */
+
+       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 */
+                   "int $0x13\n\t"
+                   "pushfw\n\t"
+                   "popw %%bx\n\t"
+                   "cli\n\t",
+                   4,
+                   OUT_CONSTRAINTS ( "=a" ( ax ), "=b" ( flags ),
+                                     "=c" ( discard_c ), "=d" ( discard_d ) ),
+                   IN_CONSTRAINTS ( "c" ( ( ( cylinder & 0xff ) << 8 ) |
+                                          ( ( cylinder >> 8 ) & 0x3 ) |
+                                          sector ),
+                                    "d" ( ( head << 8 ) | drive ),
+                                    "b" ( buf ) ),
+                   CLOBBER ( "ebp", "esi", "edi" ) );
+
+       return ( flags & CF ) ? ax : 0;
+}