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

/* Optimized rawmemchr implementation for PowerPC64/POWER7 using cmpb insn.
   Copyright (C) 2010-2016 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] rawmemchr (void *s [r3], int c [r4])  */
	.machine  power7
ENTRY (__rawmemchr)
	CALL_MCOUNT 2
	dcbt	0,r3
	clrrdi	r8,r3,3	      /* Align the address to doubleword boundary.  */

	/* 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.  */

	rlwinm	r6,r3,3,26,28 /* Calculate padding.  */
	ld	r12,0(r8)     /* Load doubleword from memory.  */
	cmpb	r5,r12,r4     /* Compare each byte against c byte.  */
#ifdef __LITTLE_ENDIAN__
	srd	r5,r5,r6
	sld	r5,r5,r6
#else
	sld	r5,r5,r6      /* Move left to discard ignored bits.  */
	srd	r5,r5,r6      /* Bring the bits back as zeros.  */
#endif
	cmpdi	cr7,r5,0      /* If r5 == 0, no c bytes have been found.  */
	bne	cr7,L(done)

	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)

	/* Handle DWORD2 of pair.  */
	ldu	r12,8(r8)
	cmpb	r5,r12,r4
	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.  */

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

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

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

	/* The 'c' 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,r6
	addi	r8,r8,8

	/* r5 has the output of the cmpb instruction, that is, it contains
	   0xff in the same position as the 'c' byte in the original
	   doubleword from the string.  Use that fact to find out what is
	   the position of the byte inside the string.  */
L(done):
#ifdef __LITTLE_ENDIAN__
	addi    r0,r5,-1
	andc    r0,r0,r5
	popcntd	r0,r0	      /* Count trailing zeros.  */
#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 char.  */
	blr
END (__rawmemchr)
weak_alias (__rawmemchr,rawmemchr)
libc_hidden_builtin_def (__rawmemchr)
Commit	Line	Data
fe2f79db	1	/* Optimized rawmemchr implementation for PowerPC64/POWER7 using cmpb insn.
f7a9f785	2	Copyright (C) 2010-2016 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] rawmemchr (void s [r3], int c [r4]) /
	23	.machine power7
2d67d91a	24	ENTRY (__rawmemchr)
fe2f79db LM	25	CALL_MCOUNT 2
	26	dcbt 0,r3
	27	clrrdi r8,r3,3 /* Align the address to doubleword boundary. */
	28
	29	/* Replicate byte to doubleword. */
466b0393 AM	30	insrdi r4,r4,8,48
466b0393 AM	31	insrdi r4,r4,16,32
fe2f79db LM	32	insrdi r4,r4,32,0
	33
	34	/* Now r4 has a doubleword of c bytes. */
	35
	36	rlwinm r6,r3,3,26,28 /* Calculate padding. */
	37	ld r12,0(r8) /* Load doubleword from memory. */
	38	cmpb r5,r12,r4 /* Compare each byte against c byte. */
466b0393 AM	39	#ifdef __LITTLE_ENDIAN__
	40	srd r5,r5,r6
	41	sld r5,r5,r6
	42	#else
fe2f79db LM	43	sld r5,r5,r6 /* Move left to discard ignored bits. */
fe2f79db LM	44	srd r5,r5,r6 /* Bring the bits back as zeros. */
466b0393	45	#endif
fe2f79db LM	46	cmpdi cr7,r5,0 /* If r5 == 0, no c bytes have been found. */
	47	bne cr7,L(done)
	48
	49	mtcrf 0x01,r8
	50
	51	/* Are we now aligned to a quadword boundary? If so, skip to
	52	the main loop. Otherwise, go through the alignment code. */
	53
	54	bt 28,L(loop)
	55
	56	/* Handle DWORD2 of pair. */
	57	ldu r12,8(r8)
	58	cmpb r5,r12,r4
	59	cmpdi cr7,r5,0
	60	bne cr7,L(done)
	61	b L(loop) /* We branch here (rather than falling through)
	62	to skip the nops due to heavy alignment
	63	of the loop below. */
	64
	65	/* Main loop to look for the end of the string. Since it's a
	66	small loop (< 8 instructions), align it to 32-bytes. */
	67	.p2align 5
	68	L(loop):
	69	/* Load two doublewords, compare and merge in a
	70	single register for speed. This is an attempt
	71	to speed up the byte-checking process for bigger strings. */
	72	ld r12,8(r8)
	73	ldu r11,16(r8)
	74	cmpb r5,r12,r4
	75	cmpb r6,r11,r4
	76	or r7,r5,r6
	77	cmpdi cr7,r7,0
	78	beq cr7,L(loop)
	79
	80	/* OK, one (or both) of the doublewords contains a 'c' byte. Check
	81	the first doubleword and decrement the address in case the first
	82	doubleword really contains a c byte. */
	83
	84	cmpdi cr6,r5,0
	85	addi r8,r8,-8
	86	bne cr6,L(done)
	87
	88	/* The 'c' byte must be in the second doubleword. Adjust the address
	89	again and move the result of cmpb to r10 so we can calculate the
	90	pointer. */
	91	mr r5,r6
	92	addi r8,r8,8
	93
	94	/* r5 has the output of the cmpb instruction, that is, it contains
	95	0xff in the same position as the 'c' byte in the original
	96	doubleword from the string. Use that fact to find out what is
	97	the position of the byte inside the string. */
	98	L(done):
466b0393 AM	99	#ifdef __LITTLE_ENDIAN__
	100	addi r0,r5,-1
	101	andc r0,r0,r5
	102	popcntd r0,r0 /* Count trailing zeros. */
	103	#else
fe2f79db	104	cntlzd r0,r5 /* Count leading zeros before the match. */
466b0393 AM	105	#endif
466b0393 AM	106	srdi r0,r0,3 /* Convert leading zeros to bytes. */
fe2f79db LM	107	add r3,r8,r0 /* Return address of the matching char. */
fe2f79db LM	108	blr
2d67d91a	109	END (__rawmemchr)
fe2f79db LM	110	weak_alias (__rawmemchr,rawmemchr)
fe2f79db LM	111	libc_hidden_builtin_def (__rawmemchr)