[thirdparty/glibc.git] / sysdeps / powerpc / powerpc32 / power7 / strncmp.S

/* Optimized strcmp implementation for POWER7/PowerPC32.
   Copyright (C) 2010-2015 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])  */

EALIGN (strncmp,5,0)

#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 rWORD3	r10
#define rWORD4	r11
#define rFEFE	r8	/* constant 0xfefefeff (-0x01010101) */
#define r7F7F	r9	/* constant 0x7f7f7f7f */
#define rNEG	r10	/* ~(word in s1 | 0x7f7f7f7f) */
#define rBITDIF	r11	/* bits that differ in s1 & s2 words */
#define rTMP	r12

	dcbt	0,rSTR1
	nop
	or	rTMP,rSTR2,rSTR1
	lis	r7F7F,0x7f7f
	dcbt	0,rSTR2
	nop
	clrlwi.	rTMP,rTMP,30
	cmplwi	cr1,rN,0
	lis	rFEFE,-0x101
	bne	L(unaligned)
/* We are word aligned so set up for two loops.  first a word
   loop, then fall into the byte loop if any residual.  */
	srwi.	rTMP,rN,2
	clrlwi	rN,rN,30
	addi	rFEFE,rFEFE,-0x101
	addi	r7F7F,r7F7F,0x7f7f
	cmplwi	cr1,rN,0
	beq	L(unaligned)

	mtctr	rTMP
	lwz	rWORD1,0(rSTR1)
	lwz	rWORD2,0(rSTR2)
	b	L(g1)

L(g0):
	lwzu	rWORD1,4(rSTR1)
	bne	cr1,L(different)
	lwzu	rWORD2,4(rSTR2)
L(g1):	add	rTMP,rFEFE,rWORD1
	nor	rNEG,r7F7F,rWORD1
	bdz	L(tail)
	and.	rTMP,rTMP,rNEG
	cmpw	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):
	slwi	rTMP, rTMP, 1
	addi    rTMP2, rTMP, -1
	andc    rTMP2, rTMP2, rTMP
	and	rWORD2, rWORD2, rTMP2		/* Mask off gunk.  */
	and	rWORD1, rWORD1, rTMP2
	rlwinm	rTMP2, rWORD2, 8, 0xffffffff	/* Byte reverse word.  */
	rlwinm	rTMP, rWORD1, 8, 0xffffffff
	rldimi	rTMP2, rWORD2, 24, 32
	rldimi	rTMP, rWORD1, 24, 32
	rlwimi	rTMP2, rWORD2, 24, 16, 23
	rlwimi	rTMP, rWORD1, 24, 16, 23
	xor.	rBITDIF, rTMP, rTMP2
	sub	rRTN, rTMP, rTMP2
	bgelr
	ori	rRTN, rTMP2, 1
	blr

L(different):
	lwz	rWORD1, -4(rSTR1)
	rlwinm	rTMP2, rWORD2, 8, 0xffffffff	/* Byte reverse word.  */
	rlwinm	rTMP, rWORD1, 8, 0xffffffff
	rldimi	rTMP2, rWORD2, 24, 32
	rldimi	rTMP, rWORD1, 24, 32
	rlwimi	rTMP2, rWORD2, 24, 16, 23
	rlwimi	rTMP, rWORD1, 24, 16, 23
	xor.	rBITDIF, rTMP, rTMP2
	sub	rRTN, rTMP, rTMP2
	bgelr
	ori	rRTN, rTMP2, 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)
	cntlzw	rBITDIF,rBITDIF
	cntlzw	rNEG,rNEG
	addi	rNEG,rNEG,7
	cmpw	cr1,rNEG,rBITDIF
	sub	rRTN,rWORD1,rWORD2
	bgelr	cr1
L(equal):
	li	rRTN,0
	blr

L(different):
	lwz	rWORD1,-4(rSTR1)
	xor.	rBITDIF,rWORD1,rWORD2
	sub	rRTN,rWORD1,rWORD2
	bgelr
L(highbit):
	ori	rRTN, rWORD2, 1
	blr
#endif

/* Oh well. In this case, we just do a byte-by-byte comparison.  */
	.align	4
L(tail):
	and.	rTMP,rTMP,rNEG
	cmpw	cr1,rWORD1,rWORD2
	bne	L(endstring)
	addi	rSTR1,rSTR1,4
	bne	cr1,L(different)
	addi	rSTR2,rSTR2,4
	cmplwi	cr1,rN,0
L(unaligned):
	mtctr	rN
	ble	cr1,L(ux)
L(uz):
	lbz	rWORD1,0(rSTR1)
	lbz	rWORD2,0(rSTR2)
	.align	4
L(u1):
	cmpwi	cr1,rWORD1,0
	bdz	L(u4)
	cmpw	rWORD1,rWORD2
	beq	cr1,L(u4)
	bne	L(u4)
	lbzu	rWORD3,1(rSTR1)
	lbzu	rWORD4,1(rSTR2)
	cmpwi	cr1,rWORD3,0
	bdz	L(u3)
	cmpw	rWORD3,rWORD4
	beq	cr1,L(u3)
	bne	L(u3)
	lbzu	rWORD1,1(rSTR1)
	lbzu	rWORD2,1(rSTR2)
	cmpwi	cr1,rWORD1,0
	bdz	L(u4)
	cmpw	rWORD1,rWORD2
	beq	cr1,L(u4)
	bne	L(u4)
	lbzu	rWORD3,1(rSTR1)
	lbzu	rWORD4,1(rSTR2)
	cmpwi	cr1,rWORD3,0
	bdz	L(u3)
	cmpw	rWORD3,rWORD4
	beq	cr1,L(u3)
	bne	L(u3)
	lbzu	rWORD1,1(rSTR1)
	lbzu	rWORD2,1(rSTR2)
	b	L(u1)

L(u3):  sub	rRTN,rWORD3,rWORD4
	blr
L(u4):	sub	rRTN,rWORD1,rWORD2
	blr
L(ux):
	li	rRTN,0
	blr
END (strncmp)
libc_hidden_builtin_def (strncmp)
Commit	Line	Data
158db122	1	/* Optimized strcmp implementation for POWER7/PowerPC32.
b168057a	2	Copyright (C) 2010-2015 Free Software Foundation, Inc.
158db122 LM	3	This file is part of the GNU C Library.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	16	License along with the GNU C Library; if not, see
59ba27a6 PE	17	<http://www.gnu.org/licenses/>. */
158db122 LM	18
158db122 LM	19	#include <sysdep.h>
158db122 LM	20
	21	/* See strlen.s for comments on how the end-of-string testing works. */
	22
	23	/* int [r3] strncmp (const char *s1 [r3],
	24	const char *s2 [r4],
	25	size_t size [r5]) */
	26
b5510883	27	EALIGN (strncmp,5,0)
158db122	28
8a7413f9	29	#define rTMP2 r0
158db122 LM	30	#define rRTN r3
	31	#define rSTR1 r3 /* first string arg */
	32	#define rSTR2 r4 /* second string arg */
	33	#define rN r5 /* max string length */
158db122 LM	34	#define rWORD1 r6 /* current word in s1 */
	35	#define rWORD2 r7 /* current word in s2 */
	36	#define rWORD3 r10
	37	#define rWORD4 r11
	38	#define rFEFE r8 /* constant 0xfefefeff (-0x01010101) */
	39	#define r7F7F r9 /* constant 0x7f7f7f7f */
	40	#define rNEG r10 /* ~(word in s1 \| 0x7f7f7f7f) */
	41	#define rBITDIF r11 /* bits that differ in s1 & s2 words */
8a7413f9	42	#define rTMP r12
158db122 LM	43
158db122 LM	44	dcbt 0,rSTR1
22700377	45	nop
158db122 LM	46	or rTMP,rSTR2,rSTR1
	47	lis r7F7F,0x7f7f
	48	dcbt 0,rSTR2
22700377	49	nop
158db122 LM	50	clrlwi. rTMP,rTMP,30
	51	cmplwi cr1,rN,0
	52	lis rFEFE,-0x101
	53	bne L(unaligned)
2ccdea26	54	/* We are word aligned so set up for two loops. first a word
158db122 LM	55	loop, then fall into the byte loop if any residual. */
	56	srwi. rTMP,rN,2
	57	clrlwi rN,rN,30
	58	addi rFEFE,rFEFE,-0x101
	59	addi r7F7F,r7F7F,0x7f7f
	60	cmplwi cr1,rN,0
	61	beq L(unaligned)
	62
	63	mtctr rTMP
	64	lwz rWORD1,0(rSTR1)
	65	lwz rWORD2,0(rSTR2)
	66	b L(g1)
	67
	68	L(g0):
	69	lwzu rWORD1,4(rSTR1)
	70	bne cr1,L(different)
	71	lwzu rWORD2,4(rSTR2)
	72	L(g1): add rTMP,rFEFE,rWORD1
	73	nor rNEG,r7F7F,rWORD1
	74	bdz L(tail)
	75	and. rTMP,rTMP,rNEG
	76	cmpw cr1,rWORD1,rWORD2
	77	beq L(g0)
	78
	79	/* OK. We've hit the end of the string. We need to be careful that
	80	we don't compare two strings as different because of gunk beyond
	81	the end of the strings... */
8a7413f9 AM	82	#ifdef __LITTLE_ENDIAN__
	83	L(endstring):
	84	slwi rTMP, rTMP, 1
	85	addi rTMP2, rTMP, -1
	86	andc rTMP2, rTMP2, rTMP
	87	and rWORD2, rWORD2, rTMP2 /* Mask off gunk. */
	88	and rWORD1, rWORD1, rTMP2
	89	rlwinm rTMP2, rWORD2, 8, 0xffffffff /* Byte reverse word. */
	90	rlwinm rTMP, rWORD1, 8, 0xffffffff
	91	rldimi rTMP2, rWORD2, 24, 32
	92	rldimi rTMP, rWORD1, 24, 32
	93	rlwimi rTMP2, rWORD2, 24, 16, 23
	94	rlwimi rTMP, rWORD1, 24, 16, 23
	95	xor. rBITDIF, rTMP, rTMP2
	96	sub rRTN, rTMP, rTMP2
	97	bgelr
	98	ori rRTN, rTMP2, 1
	99	blr
	100
	101	L(different):
	102	lwz rWORD1, -4(rSTR1)
	103	rlwinm rTMP2, rWORD2, 8, 0xffffffff /* Byte reverse word. */
	104	rlwinm rTMP, rWORD1, 8, 0xffffffff
	105	rldimi rTMP2, rWORD2, 24, 32
	106	rldimi rTMP, rWORD1, 24, 32
	107	rlwimi rTMP2, rWORD2, 24, 16, 23
	108	rlwimi rTMP, rWORD1, 24, 16, 23
	109	xor. rBITDIF, rTMP, rTMP2
	110	sub rRTN, rTMP, rTMP2
	111	bgelr
	112	ori rRTN, rTMP2, 1
	113	blr
158db122	114
8a7413f9	115	#else
158db122 LM	116	L(endstring):
	117	and rTMP,r7F7F,rWORD1
	118	beq cr1,L(equal)
	119	add rTMP,rTMP,r7F7F
	120	xor. rBITDIF,rWORD1,rWORD2
158db122 LM	121	andc rNEG,rNEG,rTMP
	122	blt L(highbit)
	123	cntlzw rBITDIF,rBITDIF
	124	cntlzw rNEG,rNEG
	125	addi rNEG,rNEG,7
	126	cmpw cr1,rNEG,rBITDIF
	127	sub rRTN,rWORD1,rWORD2
8a7413f9	128	bgelr cr1
158db122 LM	129	L(equal):
	130	li rRTN,0
	131	blr
	132
	133	L(different):
8a7413f9	134	lwz rWORD1,-4(rSTR1)
158db122 LM	135	xor. rBITDIF,rWORD1,rWORD2
158db122 LM	136	sub rRTN,rWORD1,rWORD2
8a7413f9	137	bgelr
158db122	138	L(highbit):
8a7413f9	139	ori rRTN, rWORD2, 1
158db122	140	blr
8a7413f9	141	#endif
158db122 LM	142
	143	/* Oh well. In this case, we just do a byte-by-byte comparison. */
	144	.align 4
	145	L(tail):
	146	and. rTMP,rTMP,rNEG
	147	cmpw cr1,rWORD1,rWORD2
	148	bne L(endstring)
	149	addi rSTR1,rSTR1,4
	150	bne cr1,L(different)
	151	addi rSTR2,rSTR2,4
	152	cmplwi cr1,rN,0
	153	L(unaligned):
	154	mtctr rN
	155	ble cr1,L(ux)
	156	L(uz):
	157	lbz rWORD1,0(rSTR1)
	158	lbz rWORD2,0(rSTR2)
	159	.align 4
	160	L(u1):
	161	cmpwi cr1,rWORD1,0
	162	bdz L(u4)
	163	cmpw rWORD1,rWORD2
	164	beq cr1,L(u4)
4420675c	165	bne L(u4)
158db122 LM	166	lbzu rWORD3,1(rSTR1)
158db122 LM	167	lbzu rWORD4,1(rSTR2)
158db122 LM	168	cmpwi cr1,rWORD3,0
	169	bdz L(u3)
	170	cmpw rWORD3,rWORD4
	171	beq cr1,L(u3)
4420675c	172	bne L(u3)
158db122 LM	173	lbzu rWORD1,1(rSTR1)
158db122 LM	174	lbzu rWORD2,1(rSTR2)
158db122 LM	175	cmpwi cr1,rWORD1,0
	176	bdz L(u4)
	177	cmpw rWORD1,rWORD2
	178	beq cr1,L(u4)
4420675c	179	bne L(u4)
158db122 LM	180	lbzu rWORD3,1(rSTR1)
158db122 LM	181	lbzu rWORD4,1(rSTR2)
158db122 LM	182	cmpwi cr1,rWORD3,0
	183	bdz L(u3)
	184	cmpw rWORD3,rWORD4
	185	beq cr1,L(u3)
4420675c	186	bne L(u3)
158db122 LM	187	lbzu rWORD1,1(rSTR1)
158db122 LM	188	lbzu rWORD2,1(rSTR2)
4420675c	189	b L(u1)
158db122 LM	190
	191	L(u3): sub rRTN,rWORD3,rWORD4
	192	blr
	193	L(u4): sub rRTN,rWORD1,rWORD2
	194	blr
	195	L(ux):
	196	li rRTN,0
	197	blr
b5510883	198	END (strncmp)
158db122	199	libc_hidden_builtin_def (strncmp)