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5ff6197f82
The jump to 4f will cause the NUL padding loop to run at least one time, so if string length is zero just jump to the end. Otherwise we wrongly write one NUL byte when size==0. Signed-off-by: Steven Miao <realmz6@gmail.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
85 lines
1.4 KiB
ArmAsm
85 lines
1.4 KiB
ArmAsm
/*
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* Copyright 2005-2010 Analog Devices Inc.
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*
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* Licensed under the ADI BSD license or the GPL-2 (or later)
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*/
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#include <linux/linkage.h>
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#include <asm/context.S>
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/* void *strncpy(char *dest, const char *src, size_t n);
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* R0 = address (dest)
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* R1 = address (src)
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* R2 = size
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* Returns a pointer (R0) to the destination string dest
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* we do this by not changing R0
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*/
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#ifdef CONFIG_STRNCPY_L1
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.section .l1.text
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#else
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.text
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#endif
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.align 2
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ENTRY(_strncpy)
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CC = R2 == 0;
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if CC JUMP 6f;
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P2 = R2 ; /* size */
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P0 = R0 ; /* dst*/
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P1 = R1 ; /* src*/
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LSETUP (1f, 2f) LC0 = P2;
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1:
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R1 = B [P1++] (Z);
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B [P0++] = R1;
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CC = R1 == 0;
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2:
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if CC jump 3f;
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RTS;
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/* if src is shorter than n, we need to null pad bytes in dest
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* but, we can get here when the last byte is zero, and we don't
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* want to copy an extra byte at the end, so we need to check
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*/
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3:
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R2 = LC0;
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CC = R2
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if ! CC jump 6f;
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/* if the required null padded portion is small, do it here, rather than
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* handling the overhead of memset (which is OK when things are big).
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*/
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R3 = 0x20;
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CC = R2 < R3;
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IF CC jump 4f;
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R2 += -1;
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/* Set things up for memset
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* R0 = address
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* R1 = filler byte (this case it's zero, set above)
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* R2 = count (set above)
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*/
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I1 = R0;
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R0 = RETS;
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I0 = R0;
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R0 = P0;
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pseudo_long_call _memset, p0;
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R0 = I0;
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RETS = R0;
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R0 = I1;
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RTS;
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4:
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LSETUP(5f, 5f) LC0;
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5:
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B [P0++] = R1;
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6:
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RTS;
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ENDPROC(_strncpy)
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