powerpc: Various P7-optimized string functions

1 files changed, 180 insertions, 0 deletions

diff --git a/sysdeps/powerpc/powerpc64/power7/memrchr.S b/sysdeps/powerpc/powerpc64/power7/memrchr.S
new file mode 100644
index 0000000..a56ba21
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power7/memrchr.S
@@ -0,0 +1,180 @@
+/* Optimized memrchr implementation for PowerPC64/POWER7 using cmpb insn.
+   Copyright (C) 2010 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, write to the Free
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA
+   02110-1301 USA.  */
+
+#include <sysdep.h>
+#include <bp-sym.h>
+#include <bp-asm.h>
+
+/* int [r3] memrchr (char *s [r3], int byte [r4], int size [r5])  */
+	.machine  power7
+ENTRY (BP_SYM (__memrchr))
+	CALL_MCOUNT
+	dcbt	0,r3
+	mr	r7,r3
+	add	r3,r7,r5      /* Calculate the last acceptable address.  */
+	cmpld	cr7,r3,r7     /* Is the address equal or less than r3?  */
+
+	/* Replicate BYTE to doubleword.  */
+	rlwimi	r4,r4,8,16,23
+	rlwimi	r4,r4,16,0,15
+	insrdi  r4,r4,32,0
+	bge	cr7,L(proceed)
+
+	li	r3,-1	      /* Make r11 the biggest if r4 <= 0.  */
+L(proceed):
+	li	r6,-8
+	addi	r9,r3,-1
+	clrrdi  r8,r9,3
+	addi	r8,r8,8
+	neg	r0,r3
+	rlwinm	r0,r0,3,26,28 /* Calculate padding.  */
+
+	cmpldi	r5,32
+	ble	L(small_range)
+
+	ldbrx	r12,r8,r6     /* Load reversed doubleword from memory.  */
+	cmpb	r10,r12,r4    /* Check for BYTE in DWORD1.  */
+	sld	r10,r10,r0
+	srd	r10,r10,r0
+	cmpldi	cr7,r10,0     /* If r10 == 0, no BYTE's have been found.  */
+	bne	cr7,L(done)
+
+	/* Are we done already?  */
+	addi	r9,r8,-8
+	cmpld	cr6,r9,r7
+	ble	cr6,L(null)
+
+	mtcrf   0x01,r8
+	/* Are we now aligned to a doubleword boundary?  If so, skip to
+	   the main loop.  Otherwise, go through the alignment code.  */
+	mr	r8,r9
+	bt	28,L(loop_setup)
+
+	/* Handle DWORD2 of pair.  */
+	ldbrx	r12,r8,r6
+	cmpb	r10,r12,r4
+	cmpldi	cr7,r10,0
+	bne	cr7,L(done)
+
+	/* Are we done already.  */
+	addi	r8,r8,-8
+	cmpld	cr6,r8,r7
+	ble	cr6,L(null)
+
+L(loop_setup):
+	li	r0,-16
+	sub	r5,r8,r7
+	srdi	r9,r5,4	      /* Number of loop iterations.  */
+	mtctr	r9	      /* Setup the counter.  */
+	b	L(loop)
+	/* Main loop to look for BYTE backwards in the string.  Since it's a
+	   small loop (< 8 instructions), align it to 32-bytes.  */
+	.p2align  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.  */
+
+	ldbrx	r12,r8,r6
+	ldbrx	r11,r8,r0
+	addi	r8,r8,-8
+	cmpb	r10,r12,r4
+	cmpb	r9,r11,r4
+	or	r5,r9,r10     /* Merge everything in one doubleword.  */
+	cmpldi	cr7,r5,0
+	bne	cr7,L(found)
+	addi	r8,r8,-8
+	bdnz	L(loop)
+	/* We're here because the counter reached 0, and that means we
+	   didn't have any matches for BYTE in the whole range.  Just return
+	   the original range.  */
+	addi	r9,r8,8
+	cmpld	cr6,r9,r7
+	bgt	cr6,L(loop_small)
+	b	L(null)
+
+	/* OK, one (or both) of the words contains BYTE.  Check
+	   the first word and decrement the address in case the first
+	   word really contains BYTE.  */
+	.align	4
+L(found):
+	cmpldi	cr6,r10,0
+	addi	r8,r8,8
+	bne	cr6,L(done)
+
+	/* BYTE must be in the second word.  Adjust the address
+	   again and move the result of cmpb to r10 so we can calculate the
+	   pointer.  */
+
+	mr	r10,r9
+	addi	r8,r8,-8
+
+	/* r10 has the output of the cmpb instruction, that is, it contains
+	   0xff in the same position as the BYTE in the original
+	   word from the string.  Use that to calculate the pointer.
+	   We need to make sure BYTE is *before* the end of the
+	   range.  */
+L(done):
+	cntlzd	r0,r10	      /* Count leading zeroes before the match.  */
+	srdi	r6,r0,3	      /* Convert leading zeroes to bytes.  */
+	addi	r0,r6,1
+	sub	r3,r8,r0
+	cmpld	r3,r7
+	blt	L(null)
+	blr
+
+	.align	4
+L(null):
+	li	r3,0
+	blr
+
+/* Deals with size <= 32.  */
+	.align	4
+L(small_range):
+	cmpldi	r5,0
+	beq	L(null)
+
+	ldbrx	r12,r8,r6     /* Load reversed doubleword from memory.  */
+	cmpb	r10,r12,r4    /* Check for BYTE in DWORD1.  */
+	sld	r10,r10,r0
+	srd	r10,r10,r0
+	cmpldi	cr7,r10,0
+	bne	cr7,L(done)
+
+	/* Are we done already?  */
+	addi	r8,r8,-8
+	cmpld	r8,r7
+	ble	L(null)
+	b	L(loop_small)
+
+	.p2align  5
+L(loop_small):
+	ldbrx	r12,r8,r6
+	cmpb	r10,r12,r4
+	cmpldi	cr6,r10,0
+	bne	cr6,L(done)
+	addi	r8,r8,-8
+	cmpld	r8,r7
+	ble	L(null)
+	b	L(loop_small)
+
+END (BP_SYM (__memrchr))
+weak_alias (BP_SYM (__memrchr), BP_SYM(memrchr))
+libc_hidden_builtin_def (memrchr)