ack/mach/m68020/libem/set.s

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.define .set
.sect .text
.sect .rom
.sect .data
.sect .bss
.sect .text
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ESET=2
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.set: ! d0 bitnumber
! d1 setsize in bytes
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! a1 saved d2
! a0 return address
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move.l (sp)+, a0
move.l d2, a1
move.l d1, d2
asr.l #2, d2
sub.l #1, d2
1:
clr.l -(sp)
dbf d2, 1b
move.l d0, d2
asr.l #3, d2 ! offset from sp in bytes
eor.l #3, d2 ! longs are stored in high-to-low order
cmp.l d1, d2
blt 2f
move.l #ESET, -(sp) ! bitnumber too large
move.l a1, d2
move.l a0, -(sp)
jmp (.trp)
2:
bset d0, (sp, d2.l)
move.l a1, d2
jmp (a0) ! return
.align 2