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

/* Optimized strchr implementation for PowerPC64/POWER7 using cmpb insn.
   Copyright (C) 2010-2015 Free Software Foundation, Inc.
   Contributed by Luis Machado <luisgpm@br.ibm.com>.
   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>

/* int [r3] strchr (char *s [r3], int c [r4])  */
	.machine  power7
ENTRY (strchr)
	CALL_MCOUNT 2
	dcbt	0,r3
	clrrdi	r8,r3,3	      /* Align the address to doubleword boundary.  */
	cmpdi	cr7,r4,0
	ld	r12,0(r8)     /* Load doubleword from memory.  */
	li	r0,0	      /* Doubleword with null chars to use
				 with cmpb.  */

	rlwinm	r6,r3,3,26,28 /* Calculate padding.  */

	beq	cr7,L(null_match)

	/* Replicate byte to doubleword.  */
	insrdi	r4,r4,8,48
	insrdi	r4,r4,16,32
	insrdi  r4,r4,32,0

	/* Now r4 has a doubleword of c bytes and r0 has
	   a doubleword of null bytes.  */

	cmpb	r10,r12,r4     /* Compare each byte against c byte.  */
	cmpb	r11,r12,r0     /* Compare each byte against null byte.  */

	/* Move the doublewords left and right to discard the bits that are
	   not part of the string and bring them back as zeros.  */
#ifdef __LITTLE_ENDIAN__
	srd	r10,r10,r6
	srd	r11,r11,r6
	sld	r10,r10,r6
	sld	r11,r11,r6
#else
	sld	r10,r10,r6
	sld	r11,r11,r6
	srd	r10,r10,r6
	srd	r11,r11,r6
#endif
	or	r5,r10,r11    /* OR the results to speed things up.  */
	cmpdi	cr7,r5,0      /* If r5 == 0, no c or null bytes
				 have been found.  */
	bne	cr7,L(done)

	mtcrf   0x01,r8

	/* Are we now aligned to a doubleword boundary?  If so, skip to
	   the main loop.  Otherwise, go through the alignment code.  */

	bt	28,L(loop)

	/* Handle WORD2 of pair.  */
	ldu	r12,8(r8)
	cmpb    r10,r12,r4
	cmpb	r11,r12,r0
	or	r5,r10,r11
	cmpdi	cr7,r5,0
	bne	cr7,L(done)
	b	L(loop)	      /* We branch here (rather than falling through)
				 to skip the nops due to heavy alignment
				 of the loop below.  */

	.p2align  5
L(loop):
	/* Load two doublewords, compare and merge in a
	   single register for speed.  This is an attempt
	   to speed up the null-checking process for bigger strings.  */
	ld	r12,8(r8)
	ldu	r9,16(r8)
	cmpb	r10,r12,r4
	cmpb	r11,r12,r0
	cmpb	r6,r9,r4
	cmpb	r7,r9,r0
	or	r12,r10,r11
	or	r9,r6,r7
	or	r5,r12,r9
	cmpdi	cr7,r5,0
	beq	cr7,L(loop)

	/* OK, one (or both) of the doublewords contains a c/null byte.  Check
	   the first doubleword and decrement the address in case the first
	   doubleword really contains a c/null byte.  */

	cmpdi	cr6,r12,0
	addi	r8,r8,-8
	bne	cr6,L(done)

	/* The c/null byte must be in the second doubleword.  Adjust the
	   address again and move the result of cmpb to r10 so we can calculate
	   the pointer.  */

	mr	r10,r6
	mr	r11,r7
	addi	r8,r8,8

	/* r10/r11 have the output of the cmpb instructions, that is,
	   0xff in the same position as the c/null byte in the original
	   doubleword from the string.  Use that to calculate the pointer.  */
L(done):
#ifdef __LITTLE_ENDIAN__
	addi    r3,r10,-1
	andc    r3,r3,r10
	popcntd	r0,r3
	addi    r4,r11,-1
	andc    r4,r4,r11
	cmpld	cr7,r3,r4
	bgt	cr7,L(no_match)
#else
	cntlzd	r0,r10	      /* Count leading zeros before c matches.  */
	cmpld	cr7,r11,r10
	bgt	cr7,L(no_match)
#endif
	srdi	r0,r0,3	      /* Convert leading zeros to bytes.  */
	add	r3,r8,r0      /* Return address of the matching c byte
				 or null in case c was not found.  */
	blr

	.align	4
L(no_match):
	li	r3,0
	blr

/* We are here because strchr was called with a null byte.  */
	.align	4
L(null_match):
	/* r0 has a doubleword of null bytes.  */

	cmpb	r5,r12,r0     /* Compare each byte against null bytes.  */

	/* Move the doublewords left and right to discard the bits that are
	   not part of the string and bring them back as zeros.  */
#ifdef __LITTLE_ENDIAN__
	srd	r5,r5,r6
	sld	r5,r5,r6
#else
	sld	r5,r5,r6
	srd	r5,r5,r6
#endif
	cmpdi	cr7,r5,0      /* If r10 == 0, no c or null bytes
				 have been found.  */
	bne	cr7,L(done_null)

	mtcrf   0x01,r8

	/* Are we now aligned to a quadword boundary?  If so, skip to
	   the main loop.  Otherwise, go through the alignment code.  */

	bt	28,L(loop_null)

	/* Handle WORD2 of pair.  */
	ldu	r12,8(r8)
	cmpb    r5,r12,r0
	cmpdi	cr7,r5,0
	bne	cr7,L(done_null)
	b	L(loop_null)  /* We branch here (rather than falling through)
				 to skip the nops due to heavy alignment
				 of the loop below.  */

	/* Main loop to look for the end of the string.  Since it's a
	   small loop (< 8 instructions), align it to 32-bytes.  */
	.p2align  5
L(loop_null):
	/* Load two doublewords, compare and merge in a
	   single register for speed.  This is an attempt
	   to speed up the null-checking process for bigger strings.  */
	ld	r12,8(r8)
	ldu     r11,16(r8)
	cmpb	r5,r12,r0
	cmpb	r10,r11,r0
	or	r6,r5,r10
	cmpdi	cr7,r6,0
	beq	cr7,L(loop_null)

	/* OK, one (or both) of the doublewords contains a null byte.  Check
	   the first doubleword and decrement the address in case the first
	   doubleword really contains a null byte.  */

	cmpdi	cr6,r5,0
	addi	r8,r8,-8
	bne	cr6,L(done_null)

	/* The null byte must be in the second doubleword.  Adjust the address
	   again and move the result of cmpb to r10 so we can calculate the
	   pointer.  */

	mr	r5,r10
	addi	r8,r8,8

	/* r5 has the output of the cmpb instruction, that is, it contains
	   0xff in the same position as the null byte in the original
	   doubleword from the string.  Use that to calculate the pointer.  */
L(done_null):
#ifdef __LITTLE_ENDIAN__
	addi    r0,r5,-1
	andc    r0,r0,r5
	popcntd	r0,r0
#else
	cntlzd	r0,r5	      /* Count leading zeros before the match.  */
#endif
	srdi	r0,r0,3	      /* Convert leading zeros to bytes.  */
	add	r3,r8,r0      /* Return address of the matching null byte.  */
	blr
END (strchr)
weak_alias (strchr, index)
libc_hidden_builtin_def (strchr)
Commit	Line	Data
fe2f79db	1	/* Optimized strchr implementation for PowerPC64/POWER7 using cmpb insn.
b168057a	2	Copyright (C) 2010-2015 Free Software Foundation, Inc.
fe2f79db LM	3	Contributed by Luis Machado <luisgpm@br.ibm.com>.
	4	This file is part of the GNU C Library.
	5
	6	The GNU C Library is free software; you can redistribute it and/or
	7	modify it under the terms of the GNU Lesser General Public
	8	License as published by the Free Software Foundation; either
	9	version 2.1 of the License, or (at your option) any later version.
	10
	11	The GNU C Library is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	Lesser General Public License for more details.
	15
	16	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	17	License along with the GNU C Library; if not, see
59ba27a6 PE	18	<http://www.gnu.org/licenses/>. */
fe2f79db LM	19
fe2f79db LM	20	#include <sysdep.h>
fe2f79db LM	21
	22	/* int [r3] strchr (char s [r3], int c [r4]) /
	23	.machine power7
2d67d91a	24	ENTRY (strchr)
fe2f79db LM	25	CALL_MCOUNT 2
	26	dcbt 0,r3
	27	clrrdi r8,r3,3 /* Align the address to doubleword boundary. */
	28	cmpdi cr7,r4,0
	29	ld r12,0(r8) /* Load doubleword from memory. */
	30	li r0,0 /* Doubleword with null chars to use
	31	with cmpb. */
	32
	33	rlwinm r6,r3,3,26,28 /* Calculate padding. */
	34
	35	beq cr7,L(null_match)
	36
	37	/* Replicate byte to doubleword. */
664318c3 AM	38	insrdi r4,r4,8,48
664318c3 AM	39	insrdi r4,r4,16,32
fe2f79db LM	40	insrdi r4,r4,32,0
	41
	42	/* Now r4 has a doubleword of c bytes and r0 has
	43	a doubleword of null bytes. */
	44
	45	cmpb r10,r12,r4 /* Compare each byte against c byte. */
	46	cmpb r11,r12,r0 /* Compare each byte against null byte. */
	47
	48	/* Move the doublewords left and right to discard the bits that are
	49	not part of the string and bring them back as zeros. */
664318c3 AM	50	#ifdef __LITTLE_ENDIAN__
	51	srd r10,r10,r6
	52	srd r11,r11,r6
	53	sld r10,r10,r6
	54	sld r11,r11,r6
	55	#else
fe2f79db LM	56	sld r10,r10,r6
	57	sld r11,r11,r6
	58	srd r10,r10,r6
	59	srd r11,r11,r6
664318c3	60	#endif
fe2f79db LM	61	or r5,r10,r11 /* OR the results to speed things up. */
	62	cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes
	63	have been found. */
	64	bne cr7,L(done)
	65
	66	mtcrf 0x01,r8
	67
	68	/* Are we now aligned to a doubleword boundary? If so, skip to
	69	the main loop. Otherwise, go through the alignment code. */
	70
	71	bt 28,L(loop)
	72
	73	/* Handle WORD2 of pair. */
	74	ldu r12,8(r8)
	75	cmpb r10,r12,r4
	76	cmpb r11,r12,r0
	77	or r5,r10,r11
	78	cmpdi cr7,r5,0
	79	bne cr7,L(done)
	80	b L(loop) /* We branch here (rather than falling through)
	81	to skip the nops due to heavy alignment
	82	of the loop below. */
	83
	84	.p2align 5
	85	L(loop):
	86	/* Load two doublewords, compare and merge in a
	87	single register for speed. This is an attempt
	88	to speed up the null-checking process for bigger strings. */
	89	ld r12,8(r8)
	90	ldu r9,16(r8)
	91	cmpb r10,r12,r4
	92	cmpb r11,r12,r0
	93	cmpb r6,r9,r4
	94	cmpb r7,r9,r0
	95	or r12,r10,r11
	96	or r9,r6,r7
	97	or r5,r12,r9
	98	cmpdi cr7,r5,0
	99	beq cr7,L(loop)
	100
	101	/* OK, one (or both) of the doublewords contains a c/null byte. Check
	102	the first doubleword and decrement the address in case the first
	103	doubleword really contains a c/null byte. */
	104
	105	cmpdi cr6,r12,0
	106	addi r8,r8,-8
	107	bne cr6,L(done)
	108
	109	/* The c/null byte must be in the second doubleword. Adjust the
	110	address again and move the result of cmpb to r10 so we can calculate
	111	the pointer. */
	112
	113	mr r10,r6
	114	mr r11,r7
	115	addi r8,r8,8
	116
664318c3	117	/* r10/r11 have the output of the cmpb instructions, that is,
fe2f79db LM	118	0xff in the same position as the c/null byte in the original
	119	doubleword from the string. Use that to calculate the pointer. */
	120	L(done):
664318c3 AM	121	#ifdef __LITTLE_ENDIAN__
	122	addi r3,r10,-1
	123	andc r3,r3,r10
	124	popcntd r0,r3
	125	addi r4,r11,-1
	126	andc r4,r4,r11
	127	cmpld cr7,r3,r4
fe2f79db	128	bgt cr7,L(no_match)
664318c3 AM	129	#else
	130	cntlzd r0,r10 /* Count leading zeros before c matches. */
	131	cmpld cr7,r11,r10
	132	bgt cr7,L(no_match)
	133	#endif
	134	srdi r0,r0,3 /* Convert leading zeros to bytes. */
fe2f79db LM	135	add r3,r8,r0 /* Return address of the matching c byte
	136	or null in case c was not found. */
	137	blr
	138
	139	.align 4
	140	L(no_match):
	141	li r3,0
	142	blr
	143
	144	/* We are here because strchr was called with a null byte. */
	145	.align 4
	146	L(null_match):
	147	/* r0 has a doubleword of null bytes. */
	148
	149	cmpb r5,r12,r0 /* Compare each byte against null bytes. */
	150
	151	/* Move the doublewords left and right to discard the bits that are
	152	not part of the string and bring them back as zeros. */
664318c3 AM	153	#ifdef __LITTLE_ENDIAN__
	154	srd r5,r5,r6
	155	sld r5,r5,r6
	156	#else
fe2f79db LM	157	sld r5,r5,r6
fe2f79db LM	158	srd r5,r5,r6
664318c3	159	#endif
fe2f79db LM	160	cmpdi cr7,r5,0 /* If r10 == 0, no c or null bytes
	161	have been found. */
	162	bne cr7,L(done_null)
	163
	164	mtcrf 0x01,r8
	165
	166	/* Are we now aligned to a quadword boundary? If so, skip to
	167	the main loop. Otherwise, go through the alignment code. */
	168
	169	bt 28,L(loop_null)
	170
	171	/* Handle WORD2 of pair. */
	172	ldu r12,8(r8)
	173	cmpb r5,r12,r0
	174	cmpdi cr7,r5,0
	175	bne cr7,L(done_null)
	176	b L(loop_null) /* We branch here (rather than falling through)
	177	to skip the nops due to heavy alignment
	178	of the loop below. */
	179
	180	/* Main loop to look for the end of the string. Since it's a
	181	small loop (< 8 instructions), align it to 32-bytes. */
	182	.p2align 5
	183	L(loop_null):
	184	/* Load two doublewords, compare and merge in a
	185	single register for speed. This is an attempt
	186	to speed up the null-checking process for bigger strings. */
	187	ld r12,8(r8)
	188	ldu r11,16(r8)
	189	cmpb r5,r12,r0
	190	cmpb r10,r11,r0
	191	or r6,r5,r10
	192	cmpdi cr7,r6,0
	193	beq cr7,L(loop_null)
	194
	195	/* OK, one (or both) of the doublewords contains a null byte. Check
	196	the first doubleword and decrement the address in case the first
	197	doubleword really contains a null byte. */
	198
	199	cmpdi cr6,r5,0
	200	addi r8,r8,-8
	201	bne cr6,L(done_null)
	202
	203	/* The null byte must be in the second doubleword. Adjust the address
	204	again and move the result of cmpb to r10 so we can calculate the
	205	pointer. */
	206
	207	mr r5,r10
	208	addi r8,r8,8
	209
	210	/* r5 has the output of the cmpb instruction, that is, it contains
	211	0xff in the same position as the null byte in the original
	212	doubleword from the string. Use that to calculate the pointer. */
	213	L(done_null):
664318c3 AM	214	#ifdef __LITTLE_ENDIAN__
	215	addi r0,r5,-1
	216	andc r0,r0,r5
	217	popcntd r0,r0
	218	#else
fe2f79db	219	cntlzd r0,r5 /* Count leading zeros before the match. */
664318c3	220	#endif
fe2f79db LM	221	srdi r0,r0,3 /* Convert leading zeros to bytes. */
	222	add r3,r8,r0 /* Return address of the matching null byte. */
	223	blr
2d67d91a JM	224	END (strchr)
2d67d91a JM	225	weak_alias (strchr, index)
fe2f79db	226	libc_hidden_builtin_def (strchr)