mirror of
https://github.com/cc65/cc65.git
synced 2024-12-23 19:29:37 +00:00
47 lines
465 B
ArmAsm
47 lines
465 B
ArmAsm
;
|
|
; Ullrich von Bassewitz, 17.09.1998
|
|
;
|
|
; Zero the bss segment.
|
|
;
|
|
|
|
.export zerobss
|
|
.import __BSS_RUN__, __BSS_SIZE__
|
|
.importzp ptr1
|
|
|
|
|
|
.code
|
|
|
|
zerobss:
|
|
lda #<__BSS_RUN__
|
|
sta ptr1
|
|
lda #>__BSS_RUN__
|
|
sta ptr1+1
|
|
lda #0
|
|
tay
|
|
|
|
; Clear full pages
|
|
|
|
L1: ldx #>__BSS_SIZE__
|
|
beq L3
|
|
L2: sta (ptr1),y
|
|
iny
|
|
bne L2
|
|
inc ptr1+1
|
|
dex
|
|
bne L2
|
|
|
|
; Clear remaining page (y is zero on entry)
|
|
|
|
L3: cpy #<__BSS_SIZE__
|
|
beq L4
|
|
sta (ptr1),y
|
|
iny
|
|
bne L3
|
|
|
|
; Done
|
|
|
|
L4: rts
|
|
|
|
|
|
|