33 lines
678 B
ArmAsm
33 lines
678 B
ArmAsm
.sect .text
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! Create singleton set.
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! Stack: ( bitnumber size -- set )
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!
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! Some back ends trap ESET if bitnumber is out of range. We don't
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! because the compilers tend to pass a valid bitnumber.
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.define .set
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.set:
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lwz r3, 0 (sp)
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lwz r4, 4 (sp)
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addi sp, sp, 8
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srwi r7, r3, 2
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neg r5, r3
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add sp, sp, r5 ! allocate set
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mr r6, sp ! r6 = ptr to set
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mtspr ctr, r7 ! ctr = r3 / 4
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1:
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clrrwi. r7, r4, 5 ! r7 = r4 & ~31
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beq 2f ! branch if r4 in 0..31
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li r5, 0 ! no bit, word is zero
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b 3f
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2:
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li r5, 1
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slw r5, r5, r4 ! yes bit, set bit in word
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3:
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stw r5, 0(r6) ! store word in set
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addi r4, r4, -32
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addi r6, r6, 4
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bdnz 1b ! loop ctr times
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blr
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