/*
   * Copyright 2004-2009 Analog Devices Inc.
   *
   * Licensed under the Clear BSD license or the GPL-2 (or later)
   */
  
  #include <linux/linkage.h>
  
  /* int memcmp(const void *s1, const void *s2, size_t n);
   * R0 = First Address (s1)
   * R1 = Second Address (s2)
   * R2 = count (n)
   *
   * Favours word aligned data.
   */
  
  .text
  
  .align 2
  
  ENTRY(_memcmp)
  	I1 = P3;
  	P0 = R0;			/* P0 = s1 address */
  	P3 = R1;			/* P3 = s2 Address  */
  	P2 = R2 ;			/* P2 = count */
  	CC = R2 <= 7(IU);
  	IF CC JUMP .Ltoo_small;
  	I0 = R1;			/* s2 */
  	R1 = R1 | R0;		/* OR addresses together */
  	R1 <<= 30;		/* check bottom two bits */
  	CC =  AZ;			/* AZ set if zero. */
  	IF !CC JUMP .Lbytes ;	/* Jump if addrs not aligned. */
  
  	P1 = P2 >> 2;		/* count = n/4 */
  	R3 =  3;
  	R2 = R2 & R3;		/* remainder */
  	P2 = R2;			/* set remainder */
  
  	LSETUP (.Lquad_loop_s, .Lquad_loop_e) LC0=P1;
  .Lquad_loop_s:
  #if ANOMALY_05000202
  	R0 = [P0++];
  	R1 = [I0++];
  #else
  	MNOP || R0 = [P0++] || R1 = [I0++];
  #endif
  	CC = R0 == R1;
  	IF !CC JUMP .Lquad_different;
  .Lquad_loop_e:
  	NOP;
  
  	P3 = I0;			/* s2 */
  .Ltoo_small:
  	CC = P2 == 0;		/* Check zero count*/
  	IF CC JUMP .Lfinished;	/* very unlikely*/
  
  .Lbytes:
  	LSETUP (.Lbyte_loop_s, .Lbyte_loop_e) LC0=P2;
  .Lbyte_loop_s:
  	R1 = B[P3++](Z);	/* *s2 */
  	R0 = B[P0++](Z);	/* *s1 */
  	CC = R0 == R1;
  	IF !CC JUMP .Ldifferent;
  .Lbyte_loop_e:
  	NOP;
  
  .Ldifferent:
  	R0 = R0 - R1;
  	P3 = I1;
  	RTS;
  
  .Lquad_different:
  	/* We've read two quads which don't match.
  	 * Can't just compare them, because we're
  	 * a little-endian machine, so the MSBs of
  	 * the regs occur at later addresses in the
  	 * string.
  	 * Arrange to re-read those two quads again,
  	 * byte-by-byte.
  	 */
  	P0 += -4;		/* back up to the start of the */
  	P3 = I0;		/* quads, and increase the*/
  	P2 += 4;		/* remainder count*/
  	P3 += -4;
  	JUMP .Lbytes;
  
  .Lfinished:
  	R0 = 0;
  	P3 = I1;
  	RTS;
  
  ENDPROC(_memcmp)