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authorZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
committerZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
commit5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch)
tree4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/sysdeps/powerpc/powerpc64/strncmp.S
parent199fc19d3aaaf57944ef036e15904febe877fc93 (diff)
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Prepare for radical source tree reorganization. zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/sysdeps/powerpc/powerpc64/strncmp.S')
-rw-r--r--REORG.TODO/sysdeps/powerpc/powerpc64/strncmp.S210
1 files changed, 210 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/powerpc/powerpc64/strncmp.S b/REORG.TODO/sysdeps/powerpc/powerpc64/strncmp.S
new file mode 100644
index 0000000000..076599804a
--- /dev/null
+++ b/REORG.TODO/sysdeps/powerpc/powerpc64/strncmp.S
@@ -0,0 +1,210 @@
+/* Optimized strcmp implementation for PowerPC64.
+   Copyright (C) 2003-2017 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 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>
+
+/* See strlen.s for comments on how the end-of-string testing works.  */
+
+/* int [r3] strncmp (const char *s1 [r3], const char *s2 [r4], size_t size [r5])  */
+
+#ifndef STRNCMP
+# define STRNCMP strncmp
+#endif
+
+EALIGN (STRNCMP, 4, 0)
+	CALL_MCOUNT 3
+
+#define rTMP2	r0
+#define rRTN	r3
+#define rSTR1	r3	/* first string arg */
+#define rSTR2	r4	/* second string arg */
+#define rN	r5	/* max string length */
+#define rWORD1	r6	/* current word in s1 */
+#define rWORD2	r7	/* current word in s2 */
+#define rFEFE	r8	/* constant 0xfefefefefefefeff (-0x0101010101010101) */
+#define r7F7F	r9	/* constant 0x7f7f7f7f7f7f7f7f */
+#define rNEG	r10	/* ~(word in s1 | 0x7f7f7f7f7f7f7f7f) */
+#define rBITDIF	r11	/* bits that differ in s1 & s2 words */
+#define rTMP	r12
+
+	dcbt	0,rSTR1
+	or	rTMP, rSTR2, rSTR1
+	lis	r7F7F, 0x7f7f
+	dcbt	0,rSTR2
+	clrldi.	rTMP, rTMP, 61
+	cmpldi	cr1, rN, 0
+	lis	rFEFE, -0x101
+	bne	L(unaligned)
+/* We are doubleword aligned so set up for two loops.  first a double word
+   loop, then fall into the byte loop if any residual.  */
+	srdi.	rTMP, rN, 3
+	clrldi	rN, rN, 61
+	addi	rFEFE, rFEFE, -0x101
+	addi	r7F7F, r7F7F, 0x7f7f
+	cmpldi	cr1, rN, 0
+	beq	L(unaligned)
+
+	mtctr	rTMP	/* Power4 wants mtctr 1st in dispatch group.  */
+	ld	rWORD1, 0(rSTR1)
+	ld	rWORD2, 0(rSTR2)
+	sldi	rTMP, rFEFE, 32
+	insrdi	r7F7F, r7F7F, 32, 0
+	add	rFEFE, rFEFE, rTMP
+	b	L(g1)
+
+L(g0):
+	ldu	rWORD1, 8(rSTR1)
+	bne-	cr1, L(different)
+	ldu	rWORD2, 8(rSTR2)
+L(g1):	add	rTMP, rFEFE, rWORD1
+	nor	rNEG, r7F7F, rWORD1
+	bdz	L(tail)
+	and.	rTMP, rTMP, rNEG
+	cmpd	cr1, rWORD1, rWORD2
+	beq+	L(g0)
+
+/* OK. We've hit the end of the string. We need to be careful that
+   we don't compare two strings as different because of gunk beyond
+   the end of the strings...  */
+
+#ifdef __LITTLE_ENDIAN__
+L(endstring):
+	addi    rTMP2, rTMP, -1
+	beq	cr1, L(equal)
+	andc    rTMP2, rTMP2, rTMP
+	rldimi	rTMP2, rTMP2, 1, 0
+	and	rWORD2, rWORD2, rTMP2	/* Mask off gunk.  */
+	and	rWORD1, rWORD1, rTMP2
+	cmpd	cr1, rWORD1, rWORD2
+	beq	cr1, L(equal)
+	xor	rBITDIF, rWORD1, rWORD2	/* rBITDIF has bits that differ.  */
+	neg	rNEG, rBITDIF
+	and	rNEG, rNEG, rBITDIF	/* rNEG has LS bit that differs.  */
+	cntlzd	rNEG, rNEG		/* bitcount of the bit.  */
+	andi.	rNEG, rNEG, 56		/* bitcount to LS byte that differs. */
+	sld	rWORD1, rWORD1, rNEG	/* shift left to clear MS bytes.  */
+	sld	rWORD2, rWORD2, rNEG
+	xor.	rBITDIF, rWORD1, rWORD2
+	sub	rRTN, rWORD1, rWORD2
+	blt-	L(highbit)
+	sradi	rRTN, rRTN, 63		/* must return an int.  */
+	ori	rRTN, rRTN, 1
+	blr
+L(equal):
+	li	rRTN, 0
+	blr
+
+L(different):
+	ld	rWORD1, -8(rSTR1)
+	xor	rBITDIF, rWORD1, rWORD2	/* rBITDIF has bits that differ.  */
+	neg	rNEG, rBITDIF
+	and	rNEG, rNEG, rBITDIF	/* rNEG has LS bit that differs.  */
+	cntlzd	rNEG, rNEG		/* bitcount of the bit.  */
+	andi.	rNEG, rNEG, 56		/* bitcount to LS byte that differs. */
+	sld	rWORD1, rWORD1, rNEG	/* shift left to clear MS bytes.  */
+	sld	rWORD2, rWORD2, rNEG
+	xor.	rBITDIF, rWORD1, rWORD2
+	sub	rRTN, rWORD1, rWORD2
+	blt-	L(highbit)
+	sradi	rRTN, rRTN, 63
+	ori	rRTN, rRTN, 1
+	blr
+L(highbit):
+	sradi	rRTN, rWORD2, 63
+	ori	rRTN, rRTN, 1
+	blr
+
+#else
+L(endstring):
+	and	rTMP, r7F7F, rWORD1
+	beq	cr1, L(equal)
+	add	rTMP, rTMP, r7F7F
+	xor.	rBITDIF, rWORD1, rWORD2
+	andc	rNEG, rNEG, rTMP
+	blt-	L(highbit)
+	cntlzd	rBITDIF, rBITDIF
+	cntlzd	rNEG, rNEG
+	addi	rNEG, rNEG, 7
+	cmpd	cr1, rNEG, rBITDIF
+	sub	rRTN, rWORD1, rWORD2
+	blt-	cr1, L(equal)
+	sradi	rRTN, rRTN, 63		/* must return an int.  */
+	ori	rRTN, rRTN, 1
+	blr
+L(equal):
+	li	rRTN, 0
+	blr
+
+L(different):
+	ld	rWORD1, -8(rSTR1)
+	xor.	rBITDIF, rWORD1, rWORD2
+	sub	rRTN, rWORD1, rWORD2
+	blt-	L(highbit)
+	sradi	rRTN, rRTN, 63
+	ori	rRTN, rRTN, 1
+	blr
+L(highbit):
+	sradi	rRTN, rWORD2, 63
+	ori	rRTN, rRTN, 1
+	blr
+#endif
+
+/* Oh well.  In this case, we just do a byte-by-byte comparison.  */
+	.align 4
+L(tail):
+	and.	rTMP, rTMP, rNEG
+	cmpd	cr1, rWORD1, rWORD2
+	bne-	L(endstring)
+	addi	rSTR1, rSTR1, 8
+	bne-	cr1, L(different)
+	addi	rSTR2, rSTR2, 8
+	cmpldi	cr1, rN, 0
+L(unaligned):
+	mtctr   rN	/* Power4 wants mtctr 1st in dispatch group */
+	bgt	cr1, L(uz)
+L(ux):
+	li	rRTN, 0
+	blr
+	.align 4
+L(uz):
+	lbz	rWORD1, 0(rSTR1)
+	lbz	rWORD2, 0(rSTR2)
+	nop
+	b	L(u1)
+L(u0):
+	lbzu	rWORD2, 1(rSTR2)
+L(u1):
+	bdz	L(u3)
+	cmpdi	cr1, rWORD1, 0
+	cmpd	rWORD1, rWORD2
+	beq-	cr1, L(u3)
+	lbzu	rWORD1, 1(rSTR1)
+	bne-	L(u2)
+	lbzu	rWORD2, 1(rSTR2)
+	bdz	L(u3)
+	cmpdi	cr1, rWORD1, 0
+	cmpd	rWORD1, rWORD2
+	bne-	L(u3)
+	lbzu	rWORD1, 1(rSTR1)
+	bne+	cr1, L(u0)
+
+L(u2):	lbzu	rWORD1, -1(rSTR1)
+L(u3):	sub	rRTN, rWORD1, rWORD2
+	blr
+END (STRNCMP)
+libc_hidden_builtin_def (strncmp)