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vbr: relocate to 0x00500

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This commit is contained in:
Nero 2019-03-27 23:05:46 +00:00
parent f1d11d84a2
commit 7492e99c3f
1 changed files with 15 additions and 1 deletions
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16
boot/vbr.asm
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@ -1,4 +1,4 @@
org 0x7C00 org 0
fdc: ; FDC Descriptor as per ECMA-107 fdc: ; FDC Descriptor as per ECMA-107
jmp _startup jmp _startup
@ -44,6 +44,20 @@ fdc: ; FDC Descriptor as per ECMA-107
times (62 - ($-$$)) db " " times (62 - ($-$$)) db " "
_startup: _startup:
xor ax, ax
mov ds, ax
mov es, ax
mov cx, 0x0100
mov si, 0x7C00
mov di, 0x0500
rep movsw
jmp 0x0050:.lowstart
.lowstart:
mov ax, cs
mov ds, ax
mov ss, ax
xor sp, sp
mov [fdc.drv], dl ; backup driver number mov [fdc.drv], dl ; backup driver number
mov ah, 0x08 mov ah, 0x08
int 0x13 ; required, QEMU detects 360kB as 1200kB with CHS 80 2 15 int 0x13 ; required, QEMU detects 360kB as 1200kB with CHS 80 2 15