[thirdparty/glibc.git] / sysdeps / powerpc / powerpc64 / strcmp.S

/* Optimized strcmp implementation for PowerPC64.
   Copyright (C) 1997-2014 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] strcmp (const char *s1 [r3], const char *s2 [r4])  */

EALIGN (strcmp, 4, 0)
	CALL_MCOUNT 2

#define rTMP2	r0
#define rRTN	r3
#define rSTR1	r3	/* first string arg */
#define rSTR2	r4	/* second string arg */
#define rWORD1	r5	/* current word in s1 */
#define rWORD2	r6	/* current word in s2 */
#define rFEFE	r7	/* constant 0xfefefefefefefeff (-0x0101010101010101) */
#define r7F7F	r8	/* constant 0x7f7f7f7f7f7f7f7f */
#define rNEG	r9	/* ~(word in s1 | 0x7f7f7f7f7f7f7f7f) */
#define rBITDIF	r10	/* bits that differ in s1 & s2 words */
#define rTMP	r11

	dcbt	0,rSTR1
	or	rTMP, rSTR2, rSTR1
	dcbt	0,rSTR2
	clrldi.	rTMP, rTMP, 61
	lis	rFEFE, -0x101
	bne	L(unaligned)

	ld	rWORD1, 0(rSTR1)
	ld	rWORD2, 0(rSTR2)
	lis	r7F7F, 0x7f7f
	addi	rFEFE, rFEFE, -0x101
	addi	r7F7F, r7F7F, 0x7f7f
	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
	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(unaligned):
	lbz	rWORD1, 0(rSTR1)
	lbz	rWORD2, 0(rSTR2)
	b	L(u1)

L(u0):	lbzu	rWORD1, 1(rSTR1)
	bne-	L(u4)
	lbzu	rWORD2, 1(rSTR2)
L(u1):	cmpwi	cr1, rWORD1, 0
	beq-	cr1, L(u3)
	cmpd	rWORD1, rWORD2
	bne-	L(u3)
	lbzu	rWORD1, 1(rSTR1)
	lbzu	rWORD2, 1(rSTR2)
	cmpdi	cr1, rWORD1, 0
	cmpd	rWORD1, rWORD2
	bne+	cr1, L(u0)
L(u3):	sub	rRTN, rWORD1, rWORD2
	blr
L(u4):	lbz	rWORD1, -1(rSTR1)
	sub	rRTN, rWORD1, rWORD2
	blr
END (strcmp)
libc_hidden_builtin_def (strcmp)
Commit	Line	Data
cfc91acd	1	/* Optimized strcmp implementation for PowerPC64.
d4697bc9	2	Copyright (C) 1997-2014 Free Software Foundation, Inc.
cfc91acd RM	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/>. */
cfc91acd RM	18
cfc91acd RM	19	#include <sysdep.h>
cfc91acd RM	20
	21	/* See strlen.s for comments on how the end-of-string testing works. */
	22
	23	/* int [r3] strcmp (const char s1 [r3], const char s2 [r4]) */
	24
2d67d91a	25	EALIGN (strcmp, 4, 0)
d7d06f79	26	CALL_MCOUNT 2
cfc91acd	27
8a7413f9	28	#define rTMP2 r0
cfc91acd RM	29	#define rRTN r3
	30	#define rSTR1 r3 /* first string arg */
	31	#define rSTR2 r4 /* second string arg */
cfc91acd RM	32	#define rWORD1 r5 /* current word in s1 */
cfc91acd RM	33	#define rWORD2 r6 /* current word in s2 */
482eb33c UD	34	#define rFEFE r7 /* constant 0xfefefefefefefeff (-0x0101010101010101) */
	35	#define r7F7F r8 /* constant 0x7f7f7f7f7f7f7f7f */
	36	#define rNEG r9 /* ~(word in s1 \| 0x7f7f7f7f7f7f7f7f) */
cfc91acd	37	#define rBITDIF r10 /* bits that differ in s1 & s2 words */
8a7413f9	38	#define rTMP r11
cfc91acd	39
482eb33c	40	dcbt 0,rSTR1
cfc91acd	41	or rTMP, rSTR2, rSTR1
482eb33c UD	42	dcbt 0,rSTR2
482eb33c UD	43	clrldi. rTMP, rTMP, 61
cfc91acd RM	44	lis rFEFE, -0x101
	45	bne L(unaligned)
	46
482eb33c UD	47	ld rWORD1, 0(rSTR1)
482eb33c UD	48	ld rWORD2, 0(rSTR2)
cfc91acd RM	49	lis r7F7F, 0x7f7f
cfc91acd RM	50	addi rFEFE, rFEFE, -0x101
cfc91acd	51	addi r7F7F, r7F7F, 0x7f7f
482eb33c UD	52	sldi rTMP, rFEFE, 32
	53	insrdi r7F7F, r7F7F, 32, 0
	54	add rFEFE, rFEFE, rTMP
cfc91acd RM	55	b L(g1)
cfc91acd RM	56
482eb33c	57	L(g0): ldu rWORD1, 8(rSTR1)
cfc91acd	58	bne cr1, L(different)
482eb33c	59	ldu rWORD2, 8(rSTR2)
cfc91acd RM	60	L(g1): add rTMP, rFEFE, rWORD1
cfc91acd RM	61	nor rNEG, r7F7F, rWORD1
cfc91acd	62	and. rTMP, rTMP, rNEG
482eb33c	63	cmpd cr1, rWORD1, rWORD2
cfc91acd	64	beq+ L(g0)
8a7413f9	65
cfc91acd RM	66	/* OK. We've hit the end of the string. We need to be careful that
	67	we don't compare two strings as different because of gunk beyond
	68	the end of the strings... */
8a7413f9 AM	69	#ifdef __LITTLE_ENDIAN__
	70	L(endstring):
	71	addi rTMP2, rTMP, -1
	72	beq cr1, L(equal)
	73	andc rTMP2, rTMP2, rTMP
	74	rldimi rTMP2, rTMP2, 1, 0
	75	and rWORD2, rWORD2, rTMP2 /* Mask off gunk. */
	76	and rWORD1, rWORD1, rTMP2
	77	cmpd cr1, rWORD1, rWORD2
	78	beq cr1, L(equal)
	79	xor rBITDIF, rWORD1, rWORD2 /* rBITDIF has bits that differ. */
	80	neg rNEG, rBITDIF
	81	and rNEG, rNEG, rBITDIF /* rNEG has LS bit that differs. */
	82	cntlzd rNEG, rNEG /* bitcount of the bit. */
	83	andi. rNEG, rNEG, 56 /* bitcount to LS byte that differs. */
	84	sld rWORD1, rWORD1, rNEG /* shift left to clear MS bytes. */
	85	sld rWORD2, rWORD2, rNEG
	86	xor. rBITDIF, rWORD1, rWORD2
	87	sub rRTN, rWORD1, rWORD2
	88	blt- L(highbit)
	89	sradi rRTN, rRTN, 63 /* must return an int. */
	90	ori rRTN, rRTN, 1
	91	blr
	92	L(equal):
	93	li rRTN, 0
	94	blr
	95
	96	L(different):
	97	ld rWORD1, -8(rSTR1)
	98	xor rBITDIF, rWORD1, rWORD2 /* rBITDIF has bits that differ. */
	99	neg rNEG, rBITDIF
	100	and rNEG, rNEG, rBITDIF /* rNEG has LS bit that differs. */
	101	cntlzd rNEG, rNEG /* bitcount of the bit. */
	102	andi. rNEG, rNEG, 56 /* bitcount to LS byte that differs. */
	103	sld rWORD1, rWORD1, rNEG /* shift left to clear MS bytes. */
	104	sld rWORD2, rWORD2, rNEG
	105	xor. rBITDIF, rWORD1, rWORD2
	106	sub rRTN, rWORD1, rWORD2
	107	blt- L(highbit)
	108	sradi rRTN, rRTN, 63
	109	ori rRTN, rRTN, 1
	110	blr
	111	L(highbit):
	112	sradi rRTN, rWORD2, 63
	113	ori rRTN, rRTN, 1
	114	blr
	115
	116	#else
	117	L(endstring):
cfc91acd RM	118	and rTMP, r7F7F, rWORD1
	119	beq cr1, L(equal)
	120	add rTMP, rTMP, r7F7F
	121	xor. rBITDIF, rWORD1, rWORD2
cfc91acd RM	122	andc rNEG, rNEG, rTMP
cfc91acd RM	123	blt- L(highbit)
482eb33c UD	124	cntlzd rBITDIF, rBITDIF
482eb33c UD	125	cntlzd rNEG, rNEG
cfc91acd	126	addi rNEG, rNEG, 7
482eb33c	127	cmpd cr1, rNEG, rBITDIF
cfc91acd	128	sub rRTN, rWORD1, rWORD2
482eb33c	129	blt- cr1, L(equal)
8a7413f9	130	sradi rRTN, rRTN, 63 /* must return an int. */
482eb33c UD	131	ori rRTN, rRTN, 1
482eb33c UD	132	blr
cfc91acd RM	133	L(equal):
cfc91acd RM	134	li rRTN, 0
cfc91acd RM	135	blr
	136
	137	L(different):
482eb33c	138	ld rWORD1, -8(rSTR1)
cfc91acd	139	xor. rBITDIF, rWORD1, rWORD2
cfc91acd	140	sub rRTN, rWORD1, rWORD2
482eb33c UD	141	blt- L(highbit)
	142	sradi rRTN, rRTN, 63
	143	ori rRTN, rRTN, 1
	144	blr
cfc91acd	145	L(highbit):
8a7413f9 AM	146	sradi rRTN, rWORD2, 63
8a7413f9 AM	147	ori rRTN, rRTN, 1
cfc91acd	148	blr
8a7413f9	149	#endif
cfc91acd RM	150
	151	/* Oh well. In this case, we just do a byte-by-byte comparison. */
	152	.align 4
	153	L(unaligned):
	154	lbz rWORD1, 0(rSTR1)
	155	lbz rWORD2, 0(rSTR2)
	156	b L(u1)
	157
	158	L(u0): lbzu rWORD1, 1(rSTR1)
	159	bne- L(u4)
	160	lbzu rWORD2, 1(rSTR2)
	161	L(u1): cmpwi cr1, rWORD1, 0
	162	beq- cr1, L(u3)
482eb33c	163	cmpd rWORD1, rWORD2
cfc91acd RM	164	bne- L(u3)
	165	lbzu rWORD1, 1(rSTR1)
	166	lbzu rWORD2, 1(rSTR2)
482eb33c UD	167	cmpdi cr1, rWORD1, 0
482eb33c UD	168	cmpd rWORD1, rWORD2
cfc91acd RM	169	bne+ cr1, L(u0)
cfc91acd RM	170	L(u3): sub rRTN, rWORD1, rWORD2
cfc91acd RM	171	blr
	172	L(u4): lbz rWORD1, -1(rSTR1)
	173	sub rRTN, rWORD1, rWORD2
cfc91acd	174	blr
2d67d91a	175	END (strcmp)
85dd1003	176	libc_hidden_builtin_def (strcmp)