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24 lines
362 B
ArmAsm

;
; Ullrich von Bassewitz, 25.07.2001
;
; CC65 runtime: Scale the 32 bit primary register by 16
;
.export asreax4
.importzp sreg, tmp1
asreax4:
stx tmp1
ldx sreg+1
ldy #4
@L1: cpx #$80 ; Get bit 7 into carry
ror sreg+1
ror sreg
ror tmp1
ror a
dey
bne @L1
ldx tmp1
rts