76 lines
1.1 KiB
ArmAsm
76 lines
1.1 KiB
ArmAsm
.define .lar2
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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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! Load array element, descriptor contains 2-bytes integers
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! Expects on stack: pointer to array descriptor
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! index
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! base address
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! Yields on stack: array element
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! Adapted from .aar2 and .loi
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.lar2:
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pop h
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shld .retadr1
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mov h,b
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mov l,c
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shld .bcreg
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pop h ! hl = pointer to descriptor
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pop d ! de = index
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mov a,e ! bc = index - lower bound
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sub m
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inx h
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mov c,a
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mov a,d
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sbb m
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inx h
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mov b,a
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push b ! first operand to multiply
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inx h
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inx h
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mov c,m ! bc = size
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inx h
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mov b,m
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push b ! second operand to multiply
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call .mli2 ! de = size * (index - lower bound)
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pop h ! hl = base address
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dad d ! hl = address of array[index]
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dad b ! hl= load pointer
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xra a ! clear carry bit
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mov a,b ! divide bc by 2
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rar
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mov b,a
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mov a,c
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rar
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mov c,a
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jnc 1f
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! for 1 byte array element only:
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mov a,c ! trap if bc odd and <>1
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ora b
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cnz eoddz
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dcx h
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mov e,m
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mvi d,0
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push d
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jmp 2f
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1: dcx h
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mov d,m
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dcx h
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mov e,m
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push d
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dcx b
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mov a,b
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ora c
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jnz 1b
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2: lhld .bcreg
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mov b,h
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mov c,l
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lhld .retadr1
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pchl
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