diff options
Diffstat (limited to 'memdisk/memdisk.asm')
| -rw-r--r-- | memdisk/memdisk.asm | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/memdisk/memdisk.asm b/memdisk/memdisk.asm index 6eb83302..c59704da 100644 --- a/memdisk/memdisk.asm +++ b/memdisk/memdisk.asm @@ -177,19 +177,24 @@ DoneWeird: Reset: ; Reset affects multiple drives, so we need to pass it on TRACER 'R' + xor ax,ax ; Bottom of memory + mov es,ax test dl,dl ; Always pass it on if we are resetting HD - js .pass_on ; Bit 7 set + js .hard_disk ; Bit 7 set ; Some BIOSes get very unhappy if we pass a reset floppy ; command to them and don't actually have any floppies. ; This is a bug, but we have to deal with it nontheless. ; Therefore, if we are the *ONLY* floppy drive, and the ; user didn't request HD reset, then just drop the command. - xor ax,ax ; Bottom of memory - mov es,ax ; BIOS equipment byte, top two bits + 1 == total # of floppies - test byte [es:0x410],0C0h + test byte [es:0x410],0C0h jz success - ; ... otherwise pass it to the BIOS + jmp .pass_on ; ... otherwise pass it to the BIOS +.hard_disk: + ; ... same thing for hard disks, sigh ... + cmp byte [es:0x475],1 ; BIOS variable for number of hard disks + jbe success + .pass_on: pop ax ; Drop return address popad ; Restore all registers |