[thirdparty/glibc.git] / sysdeps / powerpc / powerpc32 / power4 / strncmp.S

/* Optimized strcmp implementation for PowerPC32.
   Copyright (C) 2003-2017 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>

/* 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, 4, 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
	or	rTMP, rSTR2, rSTR1
	lis	r7F7F, 0x7f7f
	dcbt	0,rSTR2
	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	/* Power4 wants mtctr 1st in dispatch group.  */
	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	/* Power4 wants mtctr 1st in dispatch group */
	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
04067002	1	/* Optimized strcmp implementation for PowerPC32.
bfff8b1b	2	Copyright (C) 2003-2017 Free Software Foundation, Inc.
04067002 UD	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/>. */
04067002 UD	18
04067002 UD	19	#include <sysdep.h>
04067002 UD	20
	21	/* See strlen.s for comments on how the end-of-string testing works. */
	22
	23	/* int [r3] strncmp (const char s1 [r3], const char s2 [r4], size_t size [r5]) */
	24
b5510883	25	EALIGN (strncmp, 4, 0)
04067002	26
8a7413f9	27	#define rTMP2 r0
04067002 UD	28	#define rRTN r3
	29	#define rSTR1 r3 /* first string arg */
	30	#define rSTR2 r4 /* second string arg */
	31	#define rN r5 /* max string length */
04067002 UD	32	#define rWORD1 r6 /* current word in s1 */
	33	#define rWORD2 r7 /* current word in s2 */
	34	#define rWORD3 r10
	35	#define rWORD4 r11
	36	#define rFEFE r8 /* constant 0xfefefeff (-0x01010101) */
	37	#define r7F7F r9 /* constant 0x7f7f7f7f */
	38	#define rNEG r10 /* ~(word in s1 \| 0x7f7f7f7f) */
	39	#define rBITDIF r11 /* bits that differ in s1 & s2 words */
8a7413f9	40	#define rTMP r12
04067002 UD	41
	42	dcbt 0,rSTR1
	43	or rTMP, rSTR2, rSTR1
	44	lis r7F7F, 0x7f7f
	45	dcbt 0,rSTR2
	46	clrlwi. rTMP, rTMP, 30
	47	cmplwi cr1, rN, 0
	48	lis rFEFE, -0x101
	49	bne L(unaligned)
2ccdea26	50	/* We are word aligned so set up for two loops. first a word
04067002 UD	51	loop, then fall into the byte loop if any residual. */
	52	srwi. rTMP, rN, 2
	53	clrlwi rN, rN, 30
	54	addi rFEFE, rFEFE, -0x101
	55	addi r7F7F, r7F7F, 0x7f7f
7a41d99a	56	cmplwi cr1, rN, 0
04067002 UD	57	beq L(unaligned)
	58
	59	mtctr rTMP /* Power4 wants mtctr 1st in dispatch group. */
	60	lwz rWORD1, 0(rSTR1)
	61	lwz rWORD2, 0(rSTR2)
	62	b L(g1)
	63
7a41d99a	64	L(g0):
04067002 UD	65	lwzu rWORD1, 4(rSTR1)
	66	bne- cr1, L(different)
	67	lwzu rWORD2, 4(rSTR2)
	68	L(g1): add rTMP, rFEFE, rWORD1
	69	nor rNEG, r7F7F, rWORD1
	70	bdz L(tail)
	71	and. rTMP, rTMP, rNEG
	72	cmpw cr1, rWORD1, rWORD2
	73	beq+ L(g0)
7a41d99a	74
04067002 UD	75	/* OK. We've hit the end of the string. We need to be careful that
	76	we don't compare two strings as different because of gunk beyond
	77	the end of the strings... */
7a41d99a	78
8a7413f9 AM	79	#ifdef __LITTLE_ENDIAN__
	80	L(endstring):
	81	slwi rTMP, rTMP, 1
	82	addi rTMP2, rTMP, -1
	83	andc rTMP2, rTMP2, rTMP
	84	and rWORD2, rWORD2, rTMP2 /* Mask off gunk. */
	85	and rWORD1, rWORD1, rTMP2
	86	rlwinm rTMP2, rWORD2, 8, 0xffffffff /* Byte reverse word. */
	87	rlwinm rTMP, rWORD1, 8, 0xffffffff
	88	rldimi rTMP2, rWORD2, 24, 32
	89	rldimi rTMP, rWORD1, 24, 32
	90	rlwimi rTMP2, rWORD2, 24, 16, 23
	91	rlwimi rTMP, rWORD1, 24, 16, 23
	92	xor. rBITDIF, rTMP, rTMP2
	93	sub rRTN, rTMP, rTMP2
	94	bgelr+
	95	ori rRTN, rTMP2, 1
	96	blr
	97
	98	L(different):
	99	lwz rWORD1, -4(rSTR1)
	100	rlwinm rTMP2, rWORD2, 8, 0xffffffff /* Byte reverse word. */
	101	rlwinm rTMP, rWORD1, 8, 0xffffffff
	102	rldimi rTMP2, rWORD2, 24, 32
	103	rldimi rTMP, rWORD1, 24, 32
	104	rlwimi rTMP2, rWORD2, 24, 16, 23
	105	rlwimi rTMP, rWORD1, 24, 16, 23
	106	xor. rBITDIF, rTMP, rTMP2
	107	sub rRTN, rTMP, rTMP2
	108	bgelr+
	109	ori rRTN, rTMP2, 1
	110	blr
	111
	112	#else
04067002 UD	113	L(endstring):
	114	and rTMP, r7F7F, rWORD1
	115	beq cr1, L(equal)
	116	add rTMP, rTMP, r7F7F
	117	xor. rBITDIF, rWORD1, rWORD2
04067002 UD	118	andc rNEG, rNEG, rTMP
	119	blt- L(highbit)
	120	cntlzw rBITDIF, rBITDIF
	121	cntlzw rNEG, rNEG
	122	addi rNEG, rNEG, 7
	123	cmpw cr1, rNEG, rBITDIF
	124	sub rRTN, rWORD1, rWORD2
8a7413f9	125	bgelr+ cr1
04067002 UD	126	L(equal):
	127	li rRTN, 0
	128	blr
	129
	130	L(different):
8a7413f9	131	lwz rWORD1, -4(rSTR1)
04067002 UD	132	xor. rBITDIF, rWORD1, rWORD2
04067002 UD	133	sub rRTN, rWORD1, rWORD2
8a7413f9	134	bgelr+
04067002	135	L(highbit):
8a7413f9	136	ori rRTN, rWORD2, 1
04067002	137	blr
8a7413f9	138	#endif
04067002 UD	139
	140	/* Oh well. In this case, we just do a byte-by-byte comparison. */
	141	.align 4
	142	L(tail):
	143	and. rTMP, rTMP, rNEG
	144	cmpw cr1, rWORD1, rWORD2
	145	bne- L(endstring)
	146	addi rSTR1, rSTR1, 4
	147	bne- cr1, L(different)
	148	addi rSTR2, rSTR2, 4
	149	cmplwi cr1, rN, 0
	150	L(unaligned):
	151	mtctr rN /* Power4 wants mtctr 1st in dispatch group */
	152	ble cr1, L(ux)
	153	L(uz):
	154	lbz rWORD1, 0(rSTR1)
	155	lbz rWORD2, 0(rSTR2)
	156	.align 4
	157	L(u1):
	158	cmpwi cr1, rWORD1, 0
	159	bdz L(u4)
	160	cmpw rWORD1, rWORD2
	161	beq- cr1, L(u4)
4420675c	162	bne- L(u4)
04067002 UD	163	lbzu rWORD3, 1(rSTR1)
04067002 UD	164	lbzu rWORD4, 1(rSTR2)
04067002 UD	165	cmpwi cr1, rWORD3, 0
	166	bdz L(u3)
	167	cmpw rWORD3, rWORD4
	168	beq- cr1, L(u3)
4420675c	169	bne- L(u3)
04067002 UD	170	lbzu rWORD1, 1(rSTR1)
04067002 UD	171	lbzu rWORD2, 1(rSTR2)
04067002 UD	172	cmpwi cr1, rWORD1, 0
	173	bdz L(u4)
	174	cmpw rWORD1, rWORD2
	175	beq- cr1, L(u4)
4420675c	176	bne- L(u4)
04067002 UD	177	lbzu rWORD3, 1(rSTR1)
04067002 UD	178	lbzu rWORD4, 1(rSTR2)
04067002 UD	179	cmpwi cr1, rWORD3, 0
	180	bdz L(u3)
	181	cmpw rWORD3, rWORD4
	182	beq- cr1, L(u3)
4420675c	183	bne- L(u3)
04067002 UD	184	lbzu rWORD1, 1(rSTR1)
04067002 UD	185	lbzu rWORD2, 1(rSTR2)
4420675c	186	b L(u1)
04067002 UD	187
04067002 UD	188	L(u3): sub rRTN, rWORD3, rWORD4
7a41d99a	189	blr
04067002 UD	190	L(u4): sub rRTN, rWORD1, rWORD2
	191	blr
	192	L(ux):
	193	li rRTN, 0
	194	blr
b5510883	195	END (strncmp)
04067002	196	libc_hidden_builtin_def (strncmp)