2017-04-11 21:13:36 +00:00
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.file "strncpy.S"
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.section .text
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.global _strncpy
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.type _strncpy,@function
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_strncpy:
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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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cmp #0, r3
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beq 3f
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mov r1, r4 ; Preserve R1 for the return value.
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2: mov.b [r2+], r5 ; Copy bytes until...
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mov.b r5, [r4+]
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sub #1, r3
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beq 3f ; ... our count reaches zero
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cmp #0, r5
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bne 2b ; ... or we have written a NUL byte
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4: mov.b r5, [r4+] ; Continue to write further NUL bytes
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sub #1, r3
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bne 4b ; until the count reaches zero.
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3: 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 r3, r5 ; Save a copy of the byte count
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smovu ; Copy the bytes
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cmp #0, r3 ; If we have copied the number of bytes requested
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beq 1f ; then skip the next bit:
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add r4, r5, r1 ; Point to the last byte that we are supposed to write.
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sub r3, r1 ; Subtract the number of bytes left to be written.
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mov #0, r2 ; Fill the remaining bytes with NULs,
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sstr.b
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1:
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mov r4, r1 ; Return the destination 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 _strncpy, . - _strncpy
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