1
0
mirror of https://github.com/cc65/cc65.git synced 2024-12-22 12:30:41 +00:00
cc65/libsrc/runtime/popptr1.s
Colin Leroy-Mira b23a7ec407 Save two bytes in pushax and popptr1
It's not because Y must equal zero on rts that we should'nt spare one byte
and one cycle.
2024-01-19 21:14:47 +01:00

26 lines
760 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
.macpack cpu
.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 ; dey even for for 65C02 here to have Y=0 at exit!
.if (.cpu .bitand ::CPU_ISET_65SC02)
lda (sp) ; get lo byte
.else
lda (sp),y ; get lo byte
.endif
sta ptr1 ; to ptr lo
jmp incsp2
.endproc