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-rw-r--r--REORG.TODO/sysdeps/powerpc/powerpc64/power8/strncmp.S327
1 files changed, 327 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/powerpc/powerpc64/power8/strncmp.S b/REORG.TODO/sysdeps/powerpc/powerpc64/power8/strncmp.S
new file mode 100644
index 0000000000..3d8df90538
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+++ b/REORG.TODO/sysdeps/powerpc/powerpc64/power8/strncmp.S
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+/* Optimized strncmp implementation for PowerPC64/POWER8.
+   Copyright (C) 2015-2017 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>
+
+#ifndef STRNCMP
+# define STRNCMP strncmp
+#endif
+
+/* Implements the function
+
+   int [r3] strncmp (const char *s1 [r3], const char *s2 [r4], size_t [r5] n)
+
+   The implementation uses unaligned doubleword access to avoid specialized
+   code paths depending of data alignment.  Although recent powerpc64 uses
+   64K as default, the page cross handling assumes minimum page size of
+   4k.  */
+
+	.machine  power7
+EALIGN (STRNCMP, 4, 0)
+	/* Check if size is 0.  */
+	mr.	r10,r5
+	beq	cr0,L(ret0)
+
+	/* Check if [s1]+16 or [s2]+16 will cross a 4K page boundary using
+	   the code:
+
+	    (((size_t) s1) % PAGE_SIZE > (PAGE_SIZE - ITER_SIZE))
+
+	   with PAGE_SIZE being 4096 and ITER_SIZE begin 16.  */
+	rldicl	r8,r3,0,52
+	cmpldi	cr7,r8,4096-16
+	bgt	cr7,L(pagecross)
+	rldicl	r9,r4,0,52
+	cmpldi	cr7,r9,4096-16
+	bgt	cr7,L(pagecross)
+
+	/* For short string up to 16 bytes, load both s1 and s2 using
+	   unaligned dwords and compare.  */
+	ld	r7,0(r3)
+	ld	r9,0(r4)
+	li	r8,0
+	cmpb	r8,r7,r8
+	cmpb	r6,r7,r9
+	orc.	r8,r8,r6
+	bne	cr0,L(different1)
+
+	/* If the string compared are equal, but size is less or equal
+	   to 8, return 0.  */
+	cmpldi	cr7,r10,8
+	li	r9,0
+	ble	cr7,L(ret1)
+	addi	r5,r10,-8
+
+	ld	r7,8(r3)
+	ld	r9,8(r4)
+	cmpb	r8,r7,r8
+	cmpb	r6,r7,r9
+	orc.	r8,r8,r6
+	bne	cr0,L(different0)
+
+	cmpldi	cr7,r5,8
+	mr	r9,r8
+	ble	cr7,L(ret1)
+
+	/* Update pointers and size.  */
+	addi	r10,r10,-16
+	addi	r3,r3,16
+	addi	r4,r4,16
+
+	/* Now it has checked for first 16 bytes, align source1 to doubleword
+	   and adjust source2 address.  */
+L(align_8b):
+	rldicl	r5,r3,0,61
+	rldicr	r3,r3,0,60
+	subf	r4,r5,r4
+	add	r10,r10,r5
+
+	/* At this point, source1 alignment is 0 and source2 alignment is
+	   between 0 and 7.  Check is source2 alignment is 0, meaning both
+	   sources have the same alignment.  */
+	andi.	r8,r4,0x7
+	beq	cr0,L(loop_eq_align_0)
+
+	li	r5,0
+	b	L(loop_ne_align_1)
+
+	/* If source2 is unaligned to doubleword, the code needs to check
+	   on each interation if the unaligned doubleword access will cross
+	   a 4k page boundary.  */
+	.align 4
+L(loop_ne_align_0):
+	ld	r7,0(r3)
+	ld	r9,0(r4)
+	cmpb	r8,r7,r5
+	cmpb	r6,r7,r9
+	orc.	r8,r8,r6
+	bne	cr0,L(different1)
+
+	cmpldi	cr7,r10,8
+	ble	cr7,L(ret0)
+	addi	r10,r10,-8
+	addi	r3,r3,8
+	addi	r4,r4,8
+L(loop_ne_align_1):
+	rldicl	r9,r4,0,52
+	cmpldi	r7,r9,4088
+	ble	cr7,L(loop_ne_align_0)
+	cmpdi	cr7,r10,0
+	beq	cr7,L(ret0)
+
+	lbz	r9,0(r3)
+	lbz	r8,0(r4)
+	cmplw	cr7,r9,r8
+	bne	cr7,L(byte_ne_4)
+	cmpdi	cr7,r9,0
+	beq	cr7,L(size_reached_0)
+
+	li	r9,r7
+	addi	r8,r3,1
+	mtctr	r9
+	addi	r4,r4,1
+	addi	r10,r10,-1
+	addi	r3,r3,8
+
+	/* The unaligned read of source2 will cross a 4K page boundary,
+	   and the different byte or NULL maybe be in the remaining page
+	   bytes.  Since it can not use the unaligned load the algorithm
+	   reads and compares 8 bytes to keep source1 doubleword aligned.  */
+	.align 4
+L(loop_ne_align_byte):
+	cmpdi	cr7,r10,0
+	addi	r10,r10,-1
+	beq	cr7,L(ret0)
+	lbz	r9,0(r8)
+	lbz	r7,0(r4)
+	addi	r8,r8,1
+	addi	r4,r4,1
+	cmplw	cr7,r9,r7
+	cmpdi	cr5,r9,0
+	bne	cr7,L(size_reached_2)
+	beq	cr5,L(size_reached_0)
+	bdnz	L(loop_ne_align_byte)
+
+	cmpdi	cr7,r10,0
+	bne+	cr7,L(loop_ne_align_0)
+
+	.align 4
+L(ret0):
+	li	r9,0
+L(ret1):
+	mr	r3,r9
+	blr
+
+	/* The code now check if r8 and r10 are different by issuing a
+	   cmpb and shift the result based on its output:
+
+	#ifdef __LITTLE_ENDIAN__
+	  leadzero = (__builtin_ffsl (z1) - 1);
+	  leadzero = leadzero > (n-1)*8 ? (n-1)*8 : leadzero;
+	  r1 = (r1 >> leadzero) & 0xFFUL;
+	  r2 = (r2 >> leadzero) & 0xFFUL;
+	#else
+	  leadzero = __builtin_clzl (z1);
+	  leadzero = leadzero > (n-1)*8 ? (n-1)*8 : leadzero;
+	  r1 = (r1 >> (56 - leadzero)) & 0xFFUL;
+	  r2 = (r2 >> (56 - leadzero)) & 0xFFUL;
+	#endif
+	  return r1 - r2;  */
+
+	.align 4
+L(different0):
+	mr	r10,r5
+#ifdef __LITTLE_ENDIAN__
+L(different1):
+        neg	r11,r8
+        sldi	r10,r10,3
+        and	r8,r11,r8
+        addi	r10,r10,-8
+        cntlzd	r8,r8
+        subfic	r8,r8,63
+        extsw 	r8,r8
+        cmpld	cr7,r8,r10
+        ble	cr7,L(different2)
+        mr	r8,r10
+L(different2):
+        extsw	r8,r8
+#else
+L(different1):
+	addi	r10,r10,-1
+	cntlzd	r8,r8
+	sldi	r10,r10,3
+	cmpld	cr7,r8,r10
+	blt	cr7,L(different2)
+	mr	r8,r10
+L(different2):
+	subfic	r8,r8,56
+#endif
+	srd	r7,r7,r8
+	srd	r9,r9,r8
+	rldicl	r3,r7,0,56
+	rldicl	r9,r9,0,56
+	subf	r9,r9,3
+	extsw	r9,r9
+	mr	r3,r9
+	blr
+
+	/* If unaligned 16 bytes reads across a 4K page boundary, it uses
+	   a simple byte a byte comparison until the page alignment for s1
+	   is reached.  */
+	.align 4
+L(pagecross):
+	lbz	r7,0(r3)
+	lbz	r9,0(r4)
+	subfic	r8,r8,4095
+	cmplw	cr7,r9,r7
+	bne	cr7,L(byte_ne_3)
+	cmpdi	cr7,r9,0
+	beq	cr7,L(byte_ne_0)
+	addi	r10,r10,-1
+	subf	r7,r8,r10
+	subf	r9,r7,r10
+	addi	r9,r9,1
+	mtctr	r9
+	b	L(pagecross_loop1)
+
+	.align 4
+L(pagecross_loop0):
+	beq	cr7,L(ret0)
+	lbz	r9,0(r3)
+	lbz	r8,0(r4)
+	addi	r10,r10,-1
+	cmplw	cr7,r9,r8
+	cmpdi	cr5,r9,0
+	bne	r7,L(byte_ne_2)
+	beq	r5,L(byte_ne_0)
+L(pagecross_loop1):
+	cmpdi	cr7,r10,0
+	addi	r3,r3,1
+	addi	r4,r4,1
+	bdnz	L(pagecross_loop0)
+	cmpdi	cr7,r7,0
+	li	r9,0
+	bne+	cr7,L(align_8b)
+	b	L(ret1)
+
+	/* If both source1 and source2 are doubleword aligned, there is no
+	   need for page boundary cross checks.  */
+	.align 4
+L(loop_eq_align_0):
+	ld	r7,0(r3)
+	ld	r9,0(r4)
+	cmpb	r8,r7,r8
+	cmpb	r6,r7,r9
+	orc.	r8,r8,r6
+	bne	cr0,L(different1)
+
+	cmpldi	cr7,r10,8
+	ble	cr7,L(ret0)
+	addi	r9,r10,-9
+
+	li	r5,0
+	srdi	r9,r9,3
+	addi	r9,r9,1
+	mtctr	r9
+	b	L(loop_eq_align_2)
+
+	.align 4
+L(loop_eq_align_1):
+	bdz	L(ret0)
+L(loop_eq_align_2):
+	ldu	r7,8(r3)
+	addi	r10,r10,-8
+	ldu	r9,8(r4)
+	cmpb	r8,r7,r5
+	cmpb	r6,r7,r9
+	orc.	r8,r8,r6
+	beq	cr0,L(loop_eq_align_1)
+	b	L(different1)
+
+	.align 4
+L(byte_ne_0):
+	li	r7,0
+L(byte_ne_1):
+	subf	r9,r9,r7
+	extsw	r9,r9
+	b	L(ret1)
+
+	.align 4
+L(byte_ne_2):
+	extsw	r7,r9
+	mr	r9,r8
+	b	L(byte_ne_1)
+L(size_reached_0):
+	li	r10,0
+L(size_reached_1):
+	subf	r9,r9,r10
+	extsw	r9,r9
+	b	L(ret1)
+L(size_reached_2):
+	extsw	r10,r9
+	mr	r9,r7
+	b	L(size_reached_1)
+L(byte_ne_3):
+	extsw	r7,r7
+	b	L(byte_ne_1)
+L(byte_ne_4):
+	extsw	r10,r9
+	mr	r9,r8
+	b	L(size_reached_1)
+END(STRNCMP)
+libc_hidden_builtin_def(strncmp)
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-07-07 05:46:09 +0000