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-rw-r--r--sysdeps/powerpc/powerpc64/le/power10/memcmp.S179
1 files changed, 179 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/le/power10/memcmp.S b/sysdeps/powerpc/powerpc64/le/power10/memcmp.S
new file mode 100644
index 0000000000..52f244e7e7
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/le/power10/memcmp.S
@@ -0,0 +1,179 @@
+/* Optimized memcmp implementation for POWER10.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+/* TODO: Replace macros by the actual instructions when minimum binutils becomes
+   >= 2.35.  This is used to keep compatibility with older versions.  */
+#define VEXTRACTBM(rt,vrb)	 \
+	.long(((4)<<(32-6))	 \
+	      | ((rt)<<(32-11))  \
+	      | ((8)<<(32-16))	 \
+	      | ((vrb)<<(32-21)) \
+	      | 1602)
+
+#define LXVP(xtp,dq,ra)			   \
+	.long(((6)<<(32-6))		   \
+	      | ((((xtp)-32)>>1)<<(32-10)) \
+	      | ((1)<<(32-11))		   \
+	      | ((ra)<<(32-16))		   \
+	      | dq)
+
+/* Compare 32 bytes.  */
+#define COMPARE_32(vr1,vr2,offset,tail_1,tail_2)\
+	LXVP(32+vr1,offset,r3);		\
+	LXVP(32+vr2,offset,r4);		\
+	vcmpneb.  v5,vr1+1,vr2+1;	\
+	bne	  cr6,L(tail_2);	\
+	vcmpneb.  v4,vr1,vr2;		\
+	bne	  cr6,L(tail_1);	\
+
+#define TAIL(v_res,s1,s2)	\
+	vctzlsbb  r7,v_res;	\
+	vextubrx  r8,r7,s1;	\
+	vextubrx  r9,r7,s2;	\
+	subf	  r3,r9,r8;	\
+	blr;			\
+
+/* int [r3] memcmp (const char *s1 [r3], const char *s2 [r4],
+					size_t size [r5])  */
+
+#ifndef MEMCMP
+# define MEMCMP memcmp
+#endif
+	.machine  power9
+ENTRY_TOCLESS (MEMCMP, 4)
+	CALL_MCOUNT 3
+
+	cmpldi	cr6,r5,64
+	bgt	cr6,L(loop_head)
+
+/* Compare 64 bytes. This section is used for lengths <= 64 and for the last
+   bytes for larger lengths.  */
+L(last_compare):
+	li	r8,16
+
+	sldi	r9,r5,56
+	sldi	r8,r8,56
+	addi	r6,r3,16
+	addi	r7,r4,16
+
+	/* Align up to 16 bytes.  */
+	lxvl	32+v0,r3,r9
+	lxvl	32+v2,r4,r9
+
+	/* The sub. and vcmpneb. results are concatenated by the crnand in order
+	   to do a single branch. It's doing a NOT(CR0.GT AND CR6.EQ) then
+	   loading to CR0.LT.  That means r9 is not bigger than 0 and v4 is not
+	   all equal to 0.  */
+	sub.	  r9,r9,r8
+	vcmpneb.  v4,v0,v2
+	crnand	  4*cr0+lt,4*cr0+gt,4*cr6+eq
+	bt	  4*cr0+lt,L(tail1)
+
+	addi	  r3,r3,32
+	addi	  r4,r4,32
+
+	lxvl	  32+v1,r6,r9
+	lxvl	  32+v3,r7,r9
+	sub.	  r9,r9,r8
+	vcmpneb.  v5,v1,v3
+	crnand	  4*cr0+lt,4*cr0+gt,4*cr6+eq
+	bt	  4*cr0+lt,L(tail2)
+
+	addi	  r6,r3,16
+	addi	  r7,r4,16
+
+	lxvl	  32+v6,r3,r9
+	lxvl	  32+v8,r4,r9
+	sub.	  r9,r9,r8
+	vcmpneb.  v4,v6,v8
+	crnand	  4*cr0+lt,4*cr0+gt,4*cr6+eq
+	bt	  4*cr0+lt,L(tail3)
+
+	lxvl	  32+v7,r6,r9
+	lxvl	  32+v9,r7,r9
+	vcmpneb.  v5,v7,v9
+	bne	  cr6,L(tail4)
+
+L(finish):
+	/* The contents are equal.  */
+	li	r3,0
+	blr
+
+L(loop_head):
+	/* Calculate how many loops to run.  */
+	srdi.	r8,r5,7
+	beq	L(loop_tail)
+	mtctr	r8
+
+/* Main loop.  Compares 128 bytes each loop.  */
+	.p2align 5
+L(loop_128):
+	COMPARE_32(v0,v2,0,tail1,tail2)
+	COMPARE_32(v6,v8,32,tail3,tail4)
+	COMPARE_32(v10,v12,64,tail5,tail6)
+	COMPARE_32(v14,v16,96,tail7,tail8)
+
+	addi	r3,r3,128
+	addi	r4,r4,128
+	bdnz	L(loop_128)
+
+	/* Account loop comparisons.  */
+	clrldi.  r5,r5,57
+	beq	 L(finish)
+
+/* Compares 64 bytes if length is still bigger than 64 bytes.  */
+	.p2align 5
+L(loop_tail):
+	cmpldi	r5,64
+	ble	L(last_compare)
+	COMPARE_32(v0,v2,0,tail1,tail2)
+	COMPARE_32(v6,v8,32,tail3,tail4)
+	addi	r3,r3,64
+	addi	r4,r4,64
+	subi	r5,r5,64
+	b	L(last_compare)
+
+L(tail1):
+	TAIL(v4,v0,v2)
+
+L(tail2):
+	TAIL(v5,v1,v3)
+
+L(tail3):
+	TAIL(v4,v6,v8)
+
+L(tail4):
+	TAIL(v5,v7,v9)
+
+L(tail5):
+	TAIL(v4,v10,v12)
+
+L(tail6):
+	TAIL(v5,v11,v13)
+
+L(tail7):
+	TAIL(v4,v14,v16)
+
+L(tail8):
+	TAIL(v5,v15,v17)
+
+END (MEMCMP)
+libc_hidden_builtin_def (memcmp)
+weak_alias (memcmp, bcmp)