# Optimized strchr implementation for PowerPC.
 # Copyright (C) 1997 Free Software Foundation, Inc.
 # This file is part of the GNU C Library.
 #
 # The GNU C Library is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Library General Public License as
 # published by the Free Software Foundation; either version 2 of the
 # License, or (at your option) any later version.
 #
 # The GNU C Library is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 # Library General Public License for more details.
 #
 # You should have received a copy of the GNU Library General Public
 # License along with the GNU C Library; see the file COPYING.LIB.  If not,
 # write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 # Boston, MA 02111-1307, USA.

 # See strlen.s for comments on how this works.

	.section ".text"
	.align 2
	.globl strchr
	.type strchr,@function
strchr:
 # char * [r3] strchr (const char *s [r3] , int c [r4] )

 # r0:	a temporary
 # r3:	our return result.
 # r4:	byte we're looking for, spread over the whole word
 # r5:	the current word
 # r6:	the constant 0xfefefeff (-0x01010101)
 # r7:	the constant 0x7f7f7f7f
 # r8:	pointer to the current word.
 # r9:	a temporary
 # r10:	the number of bits we should ignore in the first word
 # r11:	a mask with the bits to ignore set to 0
 # r12:	a temporary
	
	rlwimi %r4,%r4,8,16,23
	li   %r11,-1
	rlwimi %r4,%r4,16,0,15
	lis  %r6,0xfeff
	lis  %r7,0x7f7f
	clrrwi %r8,%r3,2
	addi %r7,%r7,0x7f7f
	addi %r6,%r6,0xfffffeff
	rlwinm %r10,%r3,3,27,28
 # Test the first (partial?) word.
	lwz  %r5,0(%r8)
	srw  %r11,%r11,%r10
	orc  %r5,%r5,%r11
	add  %r0,%r6,%r5
	nor  %r9,%r7,%r5
	and. %r0,%r0,%r9
	xor  %r12,%r4,%r5
	orc  %r12,%r12,%r11
	b    loopentry
	
 # The loop.

loop:	lwzu %r5,4(%r8)
	and. %r0,%r0,%r9
 # Test for 0
	add  %r0,%r6,%r5
	nor  %r9,%r7,%r5
	bne  foundit
	and. %r0,%r0,%r9
 # Start test for the bytes we're looking for
	xor  %r12,%r4,%r5
loopentry:
	add  %r0,%r6,%r12
	nor  %r9,%r7,%r12
	beq  loop
 # There is a zero byte in the word, but may also be a matching byte (either
 # before or after the zero byte). In fact, we may be looking for a
 # zero byte, in which case we return a match. We guess that this hasn't
 # happened, though.
missed:	
	and. %r0,%r0,%r9
	li   %r3,0
	beqlr
 # It did happen. Decide which one was first...
 # I'm not sure if this is actually faster than a sequence of
 # rotates, compares, and branches (we use it anyway because it's shorter).
	and  %r6,%r7,%r5
	or   %r11,%r7,%r5
	and  %r0,%r7,%r12
	or   %r10,%r7,%r12
	add  %r6,%r6,%r7
	add  %r0,%r0,%r7
	nor  %r5,%r11,%r6
	nor  %r9,%r10,%r0
	cmplw %r5,%r9
	bgtlr
	cntlzw %r4,%r9
	srwi %r4,%r4,3
	add  %r3,%r8,%r4
	blr

foundit:
	and  %r0,%r7,%r12
	or   %r10,%r7,%r12
	add  %r0,%r0,%r7
	nor  %r9,%r10,%r0
	cntlzw %r4,%r9
	subi %r8,%r8,4
	srwi %r4,%r4,3
	add  %r3,%r8,%r4
	blr

0:
	.size	 strchr,0b-strchr

	.globl index
	.weak index
	.set index,strchr