70 lines
928 B
ArmAsm
70 lines
928 B
ArmAsm
.define .set
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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! Create set with one bit on
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! Expects in de-reg: size of set to be created
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! Expects on stack: bit number
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! Yields on stack: resulting set
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.set: pop h
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shld .retadr
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mov h,b
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mov l,c
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shld .bcreg
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mov a,e
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rar
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cc eoddz ! trap if size is odd
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xchg ! hl = size of set
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pop d ! de = bit number
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mov a,e ! c = bit number in byte
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ani 7
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sta .areg ! save bit number in byte
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mvi b,3 ! de = byte number
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1: xra a
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mov a,d
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rar
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mov d,a
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mov a,e
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rar
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mov e,a
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dcr b
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jnz 1b
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mov a,l ! trap if bit number is too large
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sub e
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mov a,h
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sbb d
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cc eset
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lxi b,0 ! make empty set on stack
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1: push b
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dcx h
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dcx h
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mov a,l
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ora h
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jnz 1b
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lxi h,0
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dad sp
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dad d ! hl points to byte that will contain a one
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lda .areg
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mov c,a ! c = bit number in byte
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mvi a,1
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1: dcr c
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jm 2f
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rlc
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jmp 1b
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2: mov m,a
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lhld .bcreg
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mov b,h
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mov c,l
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lhld .retadr
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pchl
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