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debug: Reduce stack usage on entry from 5 to 4 words

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Nero 2020-05-18 18:23:37 +02:00
parent 9ce6ec5476
commit 2a7087a21f
1 changed files with 5 additions and 10 deletions
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15
rom/debug.asm
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@ -28,7 +28,7 @@ pnp: db "$PnP"
dw 0 ; boot disconnect vector dw 0 ; boot disconnect vector
dw 0 ; bootstrap entry point dw 0 ; bootstrap entry point
dw 0 ; reserved dw 0 ; reserved
dw 0 zero: dw 0
name: db "rdos debug", 0 name: db "rdos debug", 0
@ -107,20 +107,15 @@ print16:
ret ret
int3entry: int3entry:
; save DS and AX ; save DS and load bss segment from IVT
push ds push ds
push ax mov ds, [cs:zero]
; DS=0
xor ax, ax
mov ds, ax
; load bss segment
mov ds, [bssvec*4] mov ds, [bssvec*4]
; pop AX and DX ; save AX so we can work with it
pop ax
mov [reg_ax], ax mov [reg_ax], ax
; pop DS, IP, CS and flags from stack
pop ax pop ax
mov [reg_ds], ax mov [reg_ds], ax
; pop IP, CS and flags from stack
pop ax pop ax
mov [reg_ip], ax mov [reg_ip], ax
pop ax pop ax