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kernel/linux-imx6_3.14.28/arch/sparc/lib/strlen.S 1.49 KB
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  /* strlen.S: Sparc optimized strlen code
   * Hand optimized from GNU libc's strlen
   * Copyright (C) 1991,1996 Free Software Foundation
   * Copyright (C) 1996,2008 David S. Miller (davem@davemloft.net)
   * Copyright (C) 1996, 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   */
  
  #include <linux/linkage.h>
  #include <asm/asm.h>
  
  #define LO_MAGIC 0x01010101
  #define HI_MAGIC 0x80808080
  
  	.text
  ENTRY(strlen)
  	mov	%o0, %o1
  	andcc	%o0, 3, %g0
  	BRANCH32(be, pt, 9f)
  	 sethi	%hi(HI_MAGIC), %o4
  	ldub	[%o0], %o5
  	BRANCH_REG_ZERO(pn, %o5, 11f)
  	 add	%o0, 1, %o0
  	andcc	%o0, 3, %g0
  	BRANCH32(be, pn, 4f)
  	 or	%o4, %lo(HI_MAGIC), %o3
  	ldub	[%o0], %o5
  	BRANCH_REG_ZERO(pn, %o5, 12f)
  	 add	%o0, 1, %o0
  	andcc	%o0, 3, %g0
  	BRANCH32(be, pt, 5f)
  	 sethi	%hi(LO_MAGIC), %o4
  	ldub	[%o0], %o5
  	BRANCH_REG_ZERO(pn, %o5, 13f)
  	 add	%o0, 1, %o0
  	BRANCH32(ba, pt, 8f)
  	 or	%o4, %lo(LO_MAGIC), %o2
  9:
  	or	%o4, %lo(HI_MAGIC), %o3
  4:
  	sethi	%hi(LO_MAGIC), %o4
  5:
  	or	%o4, %lo(LO_MAGIC), %o2
  8:
  	ld	[%o0], %o5
  2:
  	sub	%o5, %o2, %o4
  	andcc	%o4, %o3, %g0
  	BRANCH32(be, pt, 8b)
  	 add	%o0, 4, %o0
  
  	/* Check every byte. */
  	srl	%o5, 24, %g7
  	andcc	%g7, 0xff, %g0
  	BRANCH32(be, pn, 1f)
  	 add	%o0, -4, %o4
  	srl	%o5, 16, %g7
  	andcc	%g7, 0xff, %g0
  	BRANCH32(be, pn, 1f)
  	 add	%o4, 1, %o4
  	srl	%o5, 8, %g7
  	andcc	%g7, 0xff, %g0
  	BRANCH32(be, pn, 1f)
  	 add	%o4, 1, %o4
  	andcc	%o5, 0xff, %g0
  	BRANCH32_ANNUL(bne, pt, 2b)
  	 ld	[%o0], %o5
  	add	%o4, 1, %o4
  1:
  	retl
  	 sub	%o4, %o1, %o0
  11:
  	retl
  	 mov	0, %o0
  12:
  	retl
  	 mov	1, %o0
  13:
  	retl
  	 mov	2, %o0
  ENDPROC(strlen)