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kernel/linux-imx6_3.14.28/arch/blackfin/lib/strncpy.S 1.42 KB
6b13f685e   김민수   BSP 최초 추가
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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)