diff options
Diffstat (limited to 'arch/x86/boot/setup.s')
| -rw-r--r-- | arch/x86/boot/setup.s | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/x86/boot/setup.s b/arch/x86/boot/setup.s index a5c437c..41ba98c 100644 --- a/arch/x86/boot/setup.s +++ b/arch/x86/boot/setup.s @@ -31,6 +31,27 @@ _start: mov %bp, %sp BIOS_PRINT $get_data_msg + + # Get disk drive parameters + xor %ax, %ax + mov %ax, %es # ES:DI = 0x0000:0x0000 to guard + mov %ax, %di # against BIOS bugs + mov (0), %dl # Set drive boot + mov $0x8, %ah + int $0x13 + jc disk_error + + # Interrupt return: + # - CH = low eight bits of maximum cylinder number + # - CL = maximum sector number (bits 5-0) + # high two bits of maximum cylinder number (bits 7-6) + # - DH = maximum head number + xor %ch, %ch + and $0b00111111, %cl + xor %dl, %dl + mov %dx, heads + mov %cx, sectors + # TODO: get memory size # TODO: get video infos @@ -131,6 +152,13 @@ gdt_data: # the data segment descriptor gdt_end: # Global variables + +# Total amount of HDD components: +heads: # 8 significant bytes + .word 0x0 +sectors: # 6 significant bytes + .word 0x0 + gdt_descriptor: # The 6-byte GDT structure containing: # - GDT size, 2 bytes (size always less one of the real size): |