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-rw-r--r--REORG.TODO/sysdeps/powerpc/powerpc64/power7/memchr.S199
1 files changed, 199 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/powerpc/powerpc64/power7/memchr.S b/REORG.TODO/sysdeps/powerpc/powerpc64/power7/memchr.S
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+++ b/REORG.TODO/sysdeps/powerpc/powerpc64/power7/memchr.S
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+/* Optimized memchr implementation for PowerPC64/POWER7 using cmpb insn.
+   Copyright (C) 2010-2017 Free Software Foundation, Inc.
+   Contributed by Luis Machado <luisgpm@br.ibm.com>.
+   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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+/* int [r3] memchr (char *s [r3], int byte [r4], int size [r5])  */
+
+#ifndef MEMCHR
+# define MEMCHR __memchr
+#endif
+	.machine  power7
+ENTRY (MEMCHR)
+	CALL_MCOUNT 3
+	dcbt	0,r3
+	clrrdi  r8,r3,3
+	insrdi	r4,r4,8,48
+
+	/* Calculate the last acceptable address and check for possible
+	   addition overflow by using satured math:
+	   r7 = r3 + r5
+	   r7 |= -(r7 < x)  */
+	add     r7,r3,r5
+	subfc   r6,r3,r7
+	subfe   r9,r9,r9
+	extsw   r6,r9
+	or      r7,r7,r6
+
+	insrdi	r4,r4,16,32
+	cmpldi	r5,32
+	li	r9, -1
+	rlwinm	r6,r3,3,26,28 /* Calculate padding.  */
+	insrdi  r4,r4,32,0
+	addi	r7,r7,-1
+#ifdef __LITTLE_ENDIAN__
+	sld	r9,r9,r6
+#else
+	srd	r9,r9,r6
+#endif
+	ble	L(small_range)
+
+	ld	r12,0(r8)     /* Load doubleword from memory.  */
+	cmpb	r3,r12,r4     /* Check for BYTEs in DWORD1.  */
+	and	r3,r3,r9
+	clrldi	r5,r7,61      /* Byte count - 1 in last dword.  */
+	clrrdi	r7,r7,3       /* Address of last doubleword.  */
+	cmpldi	cr7,r3,0      /* Does r3 indicate we got a hit?  */
+	bne	cr7,L(done)
+
+	mtcrf   0x01,r8
+	/* Are we now aligned to a quadword boundary?  If so, skip to
+	   the main loop.  Otherwise, go through the alignment code.  */
+	bt	28,L(loop_setup)
+
+	/* Handle DWORD2 of pair.  */
+	ldu	r12,8(r8)
+	cmpb	r3,r12,r4
+	cmpldi	cr7,r3,0
+	bne	cr7,L(done)
+
+L(loop_setup):
+	/* The last dword we want to read in the loop below is the one
+	   containing the last byte of the string, ie. the dword at
+	   (s + size - 1) & ~7, or r7.  The first dword read is at
+	   r8 + 8, we read 2 * cnt dwords, so the last dword read will
+	   be at r8 + 8 + 16 * cnt - 8.  Solving for cnt gives
+	   cnt = (r7 - r8) / 16  */
+	sub	r6,r7,r8
+	srdi	r6,r6,4	      /* Number of loop iterations.  */
+	mtctr	r6            /* Setup the counter.  */
+
+	/* Main loop to look for BYTE in the string.  Since
+	   it's a small loop (8 instructions), align it to 32-bytes.  */
+	.align	5
+L(loop):
+	/* Load two doublewords, compare and merge in a
+	   single register for speed.  This is an attempt
+	   to speed up the byte-checking process for bigger strings.  */
+	ld	r12,8(r8)
+	ldu	r11,16(r8)
+	cmpb	r3,r12,r4
+	cmpb	r9,r11,r4
+	or	r6,r9,r3      /* Merge everything in one doubleword.  */
+	cmpldi	cr7,r6,0
+	bne	cr7,L(found)
+	bdnz	L(loop)
+
+	/* We may have one more dword to read.  */
+	cmpld	r8,r7
+	beqlr
+
+	ldu	r12,8(r8)
+	cmpb	r3,r12,r4
+	cmpldi	cr6,r3,0
+	bne	cr6,L(done)
+	blr
+
+	.align	4
+L(found):
+	/* OK, one (or both) of the doublewords contains BYTE.  Check
+	   the first doubleword and decrement the address in case the first
+	   doubleword really contains BYTE.  */
+	cmpldi	cr6,r3,0
+	addi	r8,r8,-8
+	bne	cr6,L(done)
+
+	/* BYTE must be in the second doubleword.  Adjust the address
+	   again and move the result of cmpb to r3 so we can calculate the
+	   pointer.  */
+
+	mr	r3,r9
+	addi	r8,r8,8
+
+	/* r3 has the output of the cmpb instruction, that is, it contains
+	   0xff in the same position as BYTE in the original
+	   doubleword from the string.  Use that to calculate the pointer.
+	   We need to make sure BYTE is *before* the end of the range.  */
+L(done):
+#ifdef __LITTLE_ENDIAN__
+	addi    r0,r3,-1
+	andc    r0,r0,r3
+	popcntd	r0,r0	      /* Count trailing zeros.  */
+#else
+	cntlzd	r0,r3	      /* Count leading zeros before the match.  */
+#endif
+	cmpld	r8,r7         /* Are we on the last dword?  */
+	srdi	r0,r0,3	      /* Convert leading/trailing zeros to bytes.  */
+	add	r3,r8,r0
+	cmpld	cr7,r0,r5     /* If on the last dword, check byte offset.  */
+	bnelr
+	blelr	cr7
+	li	r3,0
+	blr
+
+	.align	4
+L(null):
+	li	r3,0
+	blr
+
+/* Deals with size <= 32.  */
+	.align	4
+L(small_range):
+	cmpldi	r5,0
+	beq	L(null)
+	ld	r12,0(r8)     /* Load word from memory.  */
+	cmpb	r3,r12,r4     /* Check for BYTE in DWORD1.  */
+	and	r3,r3,r9
+	cmpldi	cr7,r3,0
+	clrldi	r5,r7,61      /* Byte count - 1 in last dword.  */
+	clrrdi	r7,r7,3       /* Address of last doubleword.  */
+	cmpld	r8,r7         /* Are we done already?  */
+	bne	cr7,L(done)
+	beqlr
+
+	ldu	r12,8(r8)
+	cmpb	r3,r12,r4
+	cmpldi	cr6,r3,0
+	cmpld	r8,r7
+	bne	cr6,L(done)   /* Found something.  */
+	beqlr		      /* Hit end of string (length).  */
+
+	ldu	r12,8(r8)
+	cmpb	r3,r12,r4
+	cmpldi	cr6,r3,0
+	cmpld	r8,r7
+	bne	cr6,L(done)
+	beqlr
+
+	ldu	r12,8(r8)
+	cmpb	r3,r12,r4
+	cmpldi	cr6,r3,0
+	cmpld	r8,r7
+	bne	cr6,L(done)
+	beqlr
+
+	ldu	r12,8(r8)
+	cmpb	r3,r12,r4
+	cmpldi	cr6,r3,0
+	bne	cr6,L(done)
+	blr
+
+END (MEMCHR)
+weak_alias (__memchr, memchr)
+libc_hidden_builtin_def (memchr)