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cc65/libsrc/runtime/popptr1.s
2018-07-26 14:35:26 +02:00

20 lines
638 B
ArmAsm

;
; Christian Kruger, 20-May-2018
;
; CC65 runtime: Pop 2 bytes from stack to ptr1.
; X is untouched, low byte in A, Y is defined to be 0!
.export popptr1
.import incsp2
.importzp sp, ptr1
.proc popptr1 ; 14 bytes (four usages = at least 2 bytes saved)
ldy #1
lda (sp),y ; get hi byte
sta ptr1+1 ; into ptr hi
dey ; no optimization for 65C02 here to have Y=0 at exit!
lda (sp),y ; get lo byte
sta ptr1 ; to ptr lo
jmp incsp2
.endproc