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