ack/mach/6500/libem/tle.s

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ArmAsm
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1984-12-17 11:03:13 +00:00
.define Tle
! This subroutine tests if the value in registerpair AX is
! less than or equal to zero.
! The value returned is in AX.
Tle:
tay
bpl 1f ! A >= 0
3: lda #0 ! AX <= 0
ldx #1
rts
1: beq 1f ! A = 0
2: lda #0 ! AX > 0
tax
rts
1: txa
bne 2b ! X > 0
beq 3b ! x = 0