2017-04-11 21:13:36 +00:00
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.file "strcat.S"
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.section .text
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.global _strcat
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.type _strcat,@function
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_strcat:
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;; On entry: r1 => Destination
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;; r2 => Source
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2017-10-07 00:16:47 +00:00
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#ifdef __RX_DISALLOW_STRING_INSNS__
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mov r1, r4 ; Save a copy of the dest pointer.
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1: mov.b [r4+], r5 ; Find the NUL byte at the end of R4.
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cmp #0, r5
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bne 1b
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sub #1, r4 ; Move R4 back to point at the NUL byte.
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2: mov.b [r2+], r5 ; Copy bytes from R2 to R4 until we reach a NUL byte.
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mov.b r5, [r4+]
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cmp #0, r5
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bne 2b
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rts
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#else
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2017-04-11 21:13:36 +00:00
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mov r1, r4 ; Save a copy of the dest pointer.
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mov r2, r5 ; Save a copy of the source pointer.
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mov #0, r2 ; Search for the NUL byte.
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mov #-1, r3 ; Limit on the number of bytes examined.
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suntil.b ; Find the end of the destination string.
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sub #1, r1 ; suntil.b leaves r1 pointing to the byte beyond the match.
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mov #-1, r3 ; Set a limit on the number of bytes copied.
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mov r5, r2 ; Restore the source pointer.
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smovu ; Copy source to destination
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mov r4, r1 ; Return the original dest pointer.
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rts
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2017-10-07 00:16:47 +00:00
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#endif
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.size _strcat, . - _strcat
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