mirror of
https://github.com/cc65/cc65.git
synced 2024-12-27 00:29:31 +00:00
73 lines
828 B
ArmAsm
73 lines
828 B
ArmAsm
|
;
|
||
|
|
; void __fastcall__ _sys (struct regs* r);
|
||
|
|
;
|
||
|
|
; Ullrich von Bassewitz, 16.12.1998
|
||
|
|
;
|
||
|
|
|
||
|
|
.export __sys
|
||
|
|
.import jmpvec
|
||
|
|
.importzp ptr1
|
||
|
|
|
||
|
|
|
||
|
|
__sys: sta ptr1
|
||
|
|
stx ptr1+1 ; Save the pointer to r
|
||
|
|
|
||
|
|
; Fetch the PC and store it into the jump vector
|
||
|
|
|
||
|
|
ldy #5
|
||
|
|
lda (ptr1),y
|
||
|
|
sta jmpvec+2
|
||
|
|
dey
|
||
|
|
lda (ptr1),y
|
||
|
|
sta jmpvec+1
|
||
|
|
|
||
|
|
; Get the flags, mask unnecessary bits and push them. Push a
|
||
|
|
|
||
|
|
dey
|
||
|
|
lda (ptr1),y
|
||
|
|
and #%11001011
|
||
|
|
pha
|
||
|
|
ldy #0
|
||
|
|
lda (ptr1),y
|
||
|
|
pha
|
||
|
|
|
||
|
|
; Get and assign X and Y
|
||
|
|
|
||
|
|
iny
|
||
|
|
lda (ptr1),y
|
||
|
|
tay
|
||
|
|
iny
|
||
|
|
lda (ptr1),y
|
||
|
|
tay
|
||
|
|
|
||
|
|
; Set a and the flags, call the machine code routine
|
||
|
|
|
||
|
|
pla
|
||
|
|
plp
|
||
|
|
jsr jmpvec
|
||
|
|
|
||
|
|
; Back from the routine. Save the flags and a
|
||
|
|
|
||
|
|
php
|
||
|
|
pha
|
||
|
|
|
||
|
|
; Put the register values into the regs structure
|
||
|
|
|
||
|
|
tya
|
||
|
|
ldy #2
|
||
|
|
sta (ptr1),y
|
||
|
|
dey
|
||
|
|
txa
|
||
|
|
sta (ptr1),y
|
||
|
|
dey
|
||
|
|
pla
|
||
|
|
sta (ptr1),y
|
||
|
|
ldy #3
|
||
|
|
pla
|
||
|
|
sta (ptr1),y
|
||
|
|
|
||
|
|
; Done
|
||
|
|
|
||
|
|
rts
|
||
|
|
|