[thirdparty/glibc.git] / sysdeps / powerpc / powerpc64 / power7 / strncmp.S

/* Optimized strcmp implementation for POWER7/PowerPC64.
   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)
	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 rWORD3  r10
#define rWORD4  r11
#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
	nop
	or	rTMP,rSTR2,rSTR1
	lis	r7F7F,0x7f7f
	dcbt	0,rSTR2
	nop
	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
	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)
	cmpb	rBITDIF, rWORD1, rWORD2	/* 0xff on equal bytes.  */
	addi	rNEG, rBITDIF, 1
	orc	rNEG, rNEG, rBITDIF	/* 0's below LS differing byte.  */
	sldi	rNEG, rNEG, 8		/* 1's above LS differing byte.  */
	andc	rWORD1, rWORD1, rNEG	/* mask off MS bytes.  */
	andc	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)
	cmpb	rBITDIF, rWORD1, rWORD2	/* 0xff on equal bytes.  */
	addi	rNEG, rBITDIF, 1
	orc	rNEG, rNEG, rBITDIF	/* 0's below LS differing byte.  */
	sldi	rNEG, rNEG, 8		/* 1's above LS differing byte.  */
	andc	rWORD1, rWORD1, rNEG	/* mask off MS bytes.  */
	andc	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
	ble	cr1,L(ux)
L(uz):
	lbz	rWORD1,0(rSTR1)
	lbz	rWORD2,0(rSTR2)
	.align	4
L(u1):
	cmpdi	cr1,rWORD1,0
	bdz	L(u4)
	cmpd	rWORD1,rWORD2
	beq	cr1,L(u4)
	bne	L(u4)
	lbzu	rWORD3,1(rSTR1)
	lbzu	rWORD4,1(rSTR2)
	cmpdi	cr1,rWORD3,0
	bdz	L(u3)
	cmpd	rWORD3,rWORD4
	beq	cr1,L(u3)
	bne	L(u3)
	lbzu	rWORD1,1(rSTR1)
	lbzu	rWORD2,1(rSTR2)
	cmpdi	cr1,rWORD1,0
	bdz	L(u4)
	cmpd	rWORD1,rWORD2
	beq	cr1,L(u4)
	bne	L(u4)
	lbzu	rWORD3,1(rSTR1)
	lbzu	rWORD4,1(rSTR2)
	cmpdi	cr1,rWORD3,0
	bdz	L(u3)
	cmpd	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/PowerPC64.
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
2d67d91a	27	EALIGN (strncmp,5,0)
158db122 LM	28	CALL_MCOUNT 3
158db122 LM	29
8a7413f9	30	#define rTMP2 r0
158db122 LM	31	#define rRTN r3
	32	#define rSTR1 r3 /* first string arg */
	33	#define rSTR2 r4 /* second string arg */
	34	#define rN r5 /* max string length */
158db122 LM	35	#define rWORD1 r6 /* current word in s1 */
	36	#define rWORD2 r7 /* current word in s2 */
	37	#define rWORD3 r10
	38	#define rWORD4 r11
	39	#define rFEFE r8 /* constant 0xfefefefefefefeff (-0x0101010101010101) */
	40	#define r7F7F r9 /* constant 0x7f7f7f7f7f7f7f7f */
	41	#define rNEG r10 /* ~(word in s1 \| 0x7f7f7f7f7f7f7f7f) */
	42	#define rBITDIF r11 /* bits that differ in s1 & s2 words */
8a7413f9	43	#define rTMP r12
158db122 LM	44
158db122 LM	45	dcbt 0,rSTR1
22700377	46	nop
158db122 LM	47	or rTMP,rSTR2,rSTR1
	48	lis r7F7F,0x7f7f
	49	dcbt 0,rSTR2
22700377	50	nop
158db122 LM	51	clrldi. rTMP,rTMP,61
	52	cmpldi cr1,rN,0
	53	lis rFEFE,-0x101
	54	bne L(unaligned)
2ccdea26	55	/* We are doubleword aligned so set up for two loops. first a double word
158db122 LM	56	loop, then fall into the byte loop if any residual. */
	57	srdi. rTMP,rN,3
	58	clrldi rN,rN,61
	59	addi rFEFE,rFEFE,-0x101
	60	addi r7F7F,r7F7F,0x7f7f
	61	cmpldi cr1,rN,0
	62	beq L(unaligned)
	63
	64	mtctr rTMP
	65	ld rWORD1,0(rSTR1)
	66	ld rWORD2,0(rSTR2)
	67	sldi rTMP,rFEFE,32
	68	insrdi r7F7F,r7F7F,32,0
	69	add rFEFE,rFEFE,rTMP
	70	b L(g1)
	71
	72	L(g0):
	73	ldu rWORD1,8(rSTR1)
	74	bne cr1,L(different)
	75	ldu rWORD2,8(rSTR2)
	76	L(g1): add rTMP,rFEFE,rWORD1
	77	nor rNEG,r7F7F,rWORD1
	78	bdz L(tail)
	79	and. rTMP,rTMP,rNEG
	80	cmpd cr1,rWORD1,rWORD2
	81	beq L(g0)
	82
	83	/* OK. We've hit the end of the string. We need to be careful that
	84	we don't compare two strings as different because of gunk beyond
	85	the end of the strings... */
	86
8a7413f9 AM	87	#ifdef __LITTLE_ENDIAN__
	88	L(endstring):
	89	addi rTMP2, rTMP, -1
	90	beq cr1, L(equal)
	91	andc rTMP2, rTMP2, rTMP
	92	rldimi rTMP2, rTMP2, 1, 0
	93	and rWORD2, rWORD2, rTMP2 /* Mask off gunk. */
	94	and rWORD1, rWORD1, rTMP2
	95	cmpd cr1, rWORD1, rWORD2
	96	beq cr1, L(equal)
	97	cmpb rBITDIF, rWORD1, rWORD2 /* 0xff on equal bytes. */
	98	addi rNEG, rBITDIF, 1
	99	orc rNEG, rNEG, rBITDIF /* 0's below LS differing byte. */
	100	sldi rNEG, rNEG, 8 /* 1's above LS differing byte. */
	101	andc rWORD1, rWORD1, rNEG /* mask off MS bytes. */
	102	andc rWORD2, rWORD2, rNEG
	103	xor. rBITDIF, rWORD1, rWORD2
	104	sub rRTN, rWORD1, rWORD2
	105	blt L(highbit)
	106	sradi rRTN, rRTN, 63 /* must return an int. */
	107	ori rRTN, rRTN, 1
	108	blr
	109	L(equal):
	110	li rRTN, 0
	111	blr
	112
	113	L(different):
	114	ld rWORD1, -8(rSTR1)
	115	cmpb rBITDIF, rWORD1, rWORD2 /* 0xff on equal bytes. */
	116	addi rNEG, rBITDIF, 1
	117	orc rNEG, rNEG, rBITDIF /* 0's below LS differing byte. */
	118	sldi rNEG, rNEG, 8 /* 1's above LS differing byte. */
	119	andc rWORD1, rWORD1, rNEG /* mask off MS bytes. */
	120	andc rWORD2, rWORD2, rNEG
	121	xor. rBITDIF, rWORD1, rWORD2
	122	sub rRTN, rWORD1, rWORD2
	123	blt L(highbit)
	124	sradi rRTN, rRTN, 63
	125	ori rRTN, rRTN, 1
	126	blr
	127	L(highbit):
	128	sradi rRTN, rWORD2, 63
	129	ori rRTN, rRTN, 1
	130	blr
	131
	132	#else
158db122 LM	133	L(endstring):
	134	and rTMP,r7F7F,rWORD1
	135	beq cr1,L(equal)
	136	add rTMP,rTMP,r7F7F
	137	xor. rBITDIF,rWORD1,rWORD2
158db122 LM	138	andc rNEG,rNEG,rTMP
	139	blt L(highbit)
	140	cntlzd rBITDIF,rBITDIF
	141	cntlzd rNEG,rNEG
	142	addi rNEG,rNEG,7
	143	cmpd cr1,rNEG,rBITDIF
	144	sub rRTN,rWORD1,rWORD2
	145	blt cr1,L(equal)
8a7413f9	146	sradi rRTN,rRTN,63 /* must return an int. */
158db122 LM	147	ori rRTN,rRTN,1
	148	blr
	149	L(equal):
	150	li rRTN,0
	151	blr
	152
	153	L(different):
8a7413f9	154	ld rWORD1,-8(rSTR1)
158db122 LM	155	xor. rBITDIF,rWORD1,rWORD2
	156	sub rRTN,rWORD1,rWORD2
	157	blt L(highbit)
	158	sradi rRTN,rRTN,63
	159	ori rRTN,rRTN,1
	160	blr
	161	L(highbit):
8a7413f9 AM	162	sradi rRTN,rWORD2,63
8a7413f9 AM	163	ori rRTN,rRTN,1
158db122	164	blr
8a7413f9	165	#endif
158db122 LM	166
	167	/* Oh well. In this case, we just do a byte-by-byte comparison. */
	168	.align 4
	169	L(tail):
	170	and. rTMP,rTMP,rNEG
	171	cmpd cr1,rWORD1,rWORD2
	172	bne L(endstring)
	173	addi rSTR1,rSTR1,8
	174	bne cr1,L(different)
	175	addi rSTR2,rSTR2,8
	176	cmpldi cr1,rN,0
	177	L(unaligned):
	178	mtctr rN
	179	ble cr1,L(ux)
	180	L(uz):
	181	lbz rWORD1,0(rSTR1)
	182	lbz rWORD2,0(rSTR2)
	183	.align 4
	184	L(u1):
	185	cmpdi cr1,rWORD1,0
	186	bdz L(u4)
	187	cmpd rWORD1,rWORD2
	188	beq cr1,L(u4)
4420675c	189	bne L(u4)
158db122 LM	190	lbzu rWORD3,1(rSTR1)
158db122 LM	191	lbzu rWORD4,1(rSTR2)
158db122 LM	192	cmpdi cr1,rWORD3,0
	193	bdz L(u3)
	194	cmpd rWORD3,rWORD4
	195	beq cr1,L(u3)
4420675c	196	bne L(u3)
158db122 LM	197	lbzu rWORD1,1(rSTR1)
158db122 LM	198	lbzu rWORD2,1(rSTR2)
158db122 LM	199	cmpdi cr1,rWORD1,0
	200	bdz L(u4)
	201	cmpd rWORD1,rWORD2
	202	beq cr1,L(u4)
4420675c	203	bne L(u4)
158db122 LM	204	lbzu rWORD3,1(rSTR1)
158db122 LM	205	lbzu rWORD4,1(rSTR2)
158db122 LM	206	cmpdi cr1,rWORD3,0
	207	bdz L(u3)
	208	cmpd rWORD3,rWORD4
	209	beq cr1,L(u3)
4420675c	210	bne L(u3)
158db122 LM	211	lbzu rWORD1,1(rSTR1)
158db122 LM	212	lbzu rWORD2,1(rSTR2)
4420675c	213	b L(u1)
158db122 LM	214
	215	L(u3): sub rRTN,rWORD3,rWORD4
	216	blr
	217	L(u4): sub rRTN,rWORD1,rWORD2
	218	blr
	219	L(ux):
	220	li rRTN,0
	221	blr
2d67d91a	222	END (strncmp)
158db122	223	libc_hidden_builtin_def (strncmp)