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42 lines
753 B
ArmAsm
42 lines
753 B
ArmAsm
.file "strncmp.S"
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.section .text
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.global _strncmp
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.type _strncmp,@function
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_strncmp:
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;; R1: string1
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;; R2: string2
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;; R3: max number of bytes to compare
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#ifdef __RX_DISALLOW_STRING_INSNS__
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cmp #0, r3 ; For a length of zero, return zero
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beq 4f
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2: mov.b [r1+], r4
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mov.b [r2+], r5
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cmp #0, r4
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beq 3f
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cmp #0, r5
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beq 3f
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sub #1, r3
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beq 3f
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cmp r4, r5
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beq 2b
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3: and #0xff, r4 ; We need to perform an unsigned comparison of the bytes.
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and #0xff, r5
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sub r5, r4, r1
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rts
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4: mov #0, r1
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rts
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#else
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scmpu ; Perform the string comparison
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bnc 1f ; If Carry is not set skip over
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scne.L r1 ; Set result based on Z flag
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rts ;
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1: ;
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mov #-1,r1 ; Carry not set, result should be negative
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rts ;
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#endif
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.size _strncmp, . - _strncmp
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