31 lines
589 B
ArmAsm
31 lines
589 B
ArmAsm
#
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.sect .text; .sect .rom; .sect .data; .sect .bss
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/* Exchange top two values on stack.
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* Stack: ( a b size -- b a )
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*/
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.sect .text
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.define .exg
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.exg:
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lw r4, 0(sp) ! r4 = size
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srl r5, r4, 2 ! r5 = number of words
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addiu sp, sp, 4 ! adjust stack for input/output parameter size
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mov r6, sp ! r6 = pointer to b
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addu r7, r6, r4 ! r7 = pointer to a
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! Loop to swap each pair of words.
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1:
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lw r8, 0(r6)
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lw r9, 0(r7)
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sw r9, 0(r6)
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sw r8, 0(r7)
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addiu r6, r6, 4
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addiu r7, r7, 4
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addiu r5, r5, -1
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bne r5, zero, 1b
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nop
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jr ra
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nop
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