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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: [PATCH v2 05/11] alpha: Remove bzero optimization
Date: Wed, 23 Feb 2022 11:09:15 -0300	[thread overview]
Message-ID: <20220223140921.2768062-6-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <20220223140921.2768062-1-adhemerval.zanella@linaro.org>

The symbols is not present in current POSIX specification and compiler
already generates memmove call.
---
 sysdeps/alpha/bzero.S | 109 ------------------------------------------
 1 file changed, 109 deletions(-)
 delete mode 100644 sysdeps/alpha/bzero.S

diff --git a/sysdeps/alpha/bzero.S b/sysdeps/alpha/bzero.S
deleted file mode 100644
index 4821778622..0000000000
--- a/sysdeps/alpha/bzero.S
+++ /dev/null
@@ -1,109 +0,0 @@
-/* Copyright (C) 1996-2022 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
-   <https://www.gnu.org/licenses/>.  */
-
-/* Fill a block of memory with zeros.  Optimized for the Alpha architecture:
-
-   - memory accessed as aligned quadwords only
-   - destination memory not read unless needed for good cache behaviour
-   - basic blocks arranged to optimize branch prediction for full-quadword
-     aligned memory blocks.
-   - partial head and tail quadwords constructed with byte-mask instructions
-
-   This is generally scheduled for the EV5 (got to look out for my own
-   interests :-), but with EV4 needs in mind.  There *should* be no more
-   stalls for the EV4 than there are for the EV5.
-*/
-
-
-#include <sysdep.h>
-
-	.set noat
-	.set noreorder
-
-	.text
-	.type	__bzero, @function
-	.globl	__bzero
-	.usepv	__bzero, USEPV_PROF
-
-	cfi_startproc
-
-	/* On entry to this basic block:
-	   t3 == loop counter
-	   t4 == bytes in partial final word
-	   a0 == possibly misaligned destination pointer  */
-
-	.align 3
-bzero_loop:
-	beq	t3, $tail	#
-	blbc	t3, 0f		# skip single store if count even
-
-	stq_u	zero, 0(a0)	# e0    : store one word
-	subq	t3, 1, t3	# .. e1 :
-	addq	a0, 8, a0	# e0    :
-	beq	t3, $tail	# .. e1 :
-
-0:	stq_u	zero, 0(a0)	# e0    : store two words
-	subq	t3, 2, t3	# .. e1 :
-	stq_u	zero, 8(a0)	# e0    :
-	addq	a0, 16, a0	# .. e1 :
-	bne	t3, 0b		# e1    :
-
-$tail:	bne	t4, 1f		# is there a tail to do?
-	ret			# no
-
-1:	ldq_u	t0, 0(a0)	# yes, load original data
-	mskqh	t0, t4, t0	#
-	stq_u	t0, 0(a0)	#
-	ret			#
-
-__bzero:
-#ifdef PROF
-	ldgp	gp, 0(pv)
-	lda	AT, _mcount
-	jsr	AT, (AT), _mcount
-#endif
-
-	mov	a0, v0		# e0    : move return value in place
-	beq	a1, $done	# .. e1 : early exit for zero-length store
-	and	a0, 7, t1	# e0    :
-	addq	a1, t1, a1	# e1    : add dest misalignment to count
-	srl	a1, 3, t3	# e0    : loop = count >> 3
-	and	a1, 7, t4	# .. e1 : find number of bytes in tail
-	unop			#       :
-	beq	t1, bzero_loop	# e1    : aligned head, jump right in
-
-	ldq_u	t0, 0(a0)	# e0    : load original data to mask into
-	cmpult	a1, 8, t2	# .. e1 : is this a sub-word set?
-	bne	t2, $oneq	# e1    :
-
-	mskql	t0, a0, t0	# e0    : we span words.  finish this partial
-	subq	t3, 1, t3	# e0    :
-	addq	a0, 8, a0	# .. e1 :
-	stq_u	t0, -8(a0)	# e0    :
-	br 	bzero_loop	# .. e1 :
-
-	.align 3
-$oneq:
-	mskql	t0, a0, t2	# e0    :
-	mskqh	t0, a1, t3	# e0    :
-	or	t2, t3, t0	# e1    :
-	stq_u	t0, 0(a0)	# e0    :
-
-$done:	ret
-
-	cfi_endproc
-weak_alias (__bzero, bzero)
-- 
2.32.0


  parent reply	other threads:[~2022-02-23 14:09 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-23 14:09 [PATCH v2 00/11] Remove bcopy and bzero optimizations Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 01/11] ia64: Remove bcopy Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 02/11] powerpc: Remove bcopy optimizations Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 03/11] i386: " Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 04/11] x86_64: " Adhemerval Zanella
2022-05-12 19:28   ` Sunil Pandey
2022-02-23 14:09 ` Adhemerval Zanella [this message]
2022-02-23 14:09 ` [PATCH v2 06/11] ia64: Remove bzero optimization Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 07/11] sparc: " Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 08/11] powerpc: Remove powerpc32 bzero optimizations Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 09/11] powerpc: Remove powerpc64 " Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 10/11] s390: Remove " Adhemerval Zanella
2022-02-23 14:09 ` [PATCH v2 11/11] i686: " Adhemerval Zanella
2022-02-23 14:13 ` [PATCH v2 00/11] Remove bcopy and " Adhemerval Zanella

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