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4c01126896
There exist optimized memcpy functions on s390, but no optimized mempcpy. This patch adds mempcpy entry points in memcpy.S files, which use the memcpy implementation. Now mempcpy itself is also an IFUNC function as memcpy is and the variants are listed in ifunc-impl-list.c. The s390 string.h does not define _HAVE_STRING_ARCH_mempcpy. Instead mempcpy string/string.h inlines memcpy() + n. If n is constant and small enough, GCC emits instructions like mvi or mvc and avoids the function call to memcpy. If n is not constant, then memcpy is called and n is added afterwards. If _HAVE_STRING_ARCH_mempcpy would be defined, mempcpy would be called in every case. According to PR70140 "Inefficient expansion of __builtin_mempcpy" (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70140) GCC should handle a call to mempcpy in the same way as memcpy. Then either the mempcpy macro in string/string.h has to be removed or _HAVE_STRING_ARCH_mempcpy has to be defined for S390. ChangeLog: [BZ #19765] * sysdeps/s390/mempcpy.S: New File. * sysdeps/s390/multiarch/mempcpy.c: Likewise. * sysdeps/s390/multiarch/Makefile (sysdep_routines): Add mempcpy. * sysdeps/s390/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list): Add mempcpy variants. * sysdeps/s390/s390-32/memcpy.S: Add mempcpy entry point. (memcpy): Adjust to be usable from mempcpy entry point. (__memcpy_mvcle): Likewise. * sysdeps/s390/s390-64/memcpy.S: Likewise. * sysdeps/s390/s390-32/multiarch/memcpy-s390.S: Add entry points ____mempcpy_z196, ____mempcpy_z10 and add __GI_ symbols for mempcpy. (__memcpy_z196): Adjust to be usable from mempcpy entry point. (__memcpy_z10): Likewise. * sysdeps/s390/s390-64/multiarch/memcpy-s390x.S: Likewise.
93 lines
2.7 KiB
ArmAsm
93 lines
2.7 KiB
ArmAsm
/* memcpy - copy a block from source to destination. S/390 version.
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Copyright (C) 2012-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include "sysdep.h"
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#include "asm-syntax.h"
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/* INPUT PARAMETERS
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%r2 = address of destination memory area
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%r3 = address of source memory area
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%r4 = number of bytes to copy. */
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.text
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ENTRY(__mempcpy)
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.machine "g5"
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lr %r1,%r2 # Use as dest
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la %r2,0(%r4,%r2) # Return dest + n
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j .L_G5_start
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END(__mempcpy)
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#ifndef USE_MULTIARCH
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libc_hidden_def (__mempcpy)
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weak_alias (__mempcpy, mempcpy)
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libc_hidden_builtin_def (mempcpy)
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#endif
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ENTRY(memcpy)
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.machine "g5"
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lr %r1,%r2 # r1: Use as dest ; r2: Return dest
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.L_G5_start:
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st %r13,52(%r15)
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.cfi_offset 13, -44
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basr %r13,0
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.L_G5_16:
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ltr %r4,%r4
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je .L_G5_4
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ahi %r4,-1
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lr %r5,%r4
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srl %r5,8
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ltr %r5,%r5
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jne .L_G5_13
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ex %r4,.L_G5_17-.L_G5_16(%r13)
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.L_G5_4:
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l %r13,52(%r15)
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br %r14
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.L_G5_13:
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chi %r5,4096 # Switch to mvcle for copies >1MB
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jh __memcpy_mvcle
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.L_G5_12:
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mvc 0(256,%r1),0(%r3)
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la %r1,256(%r1)
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la %r3,256(%r3)
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brct %r5,.L_G5_12
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ex %r4,.L_G5_17-.L_G5_16(%r13)
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j .L_G5_4
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.L_G5_17:
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mvc 0(1,%r1),0(%r3)
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END(memcpy)
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#ifndef USE_MULTIARCH
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libc_hidden_builtin_def (memcpy)
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#endif
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ENTRY(__memcpy_mvcle)
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# Using as standalone function will result in unexpected
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# results since the length field is incremented by 1 in order to
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# compensate the changes already done in the functions above.
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lr %r0,%r2 # backup return dest [ + n ]
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ahi %r4,1 # length + 1
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lr %r5,%r4 # source length
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lr %r4,%r3 # source address
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lr %r2,%r1 # destination address
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lr %r3,%r5 # destination length = source length
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.L_MVCLE_1:
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mvcle %r2,%r4,0 # thats it, MVCLE is your friend
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jo .L_MVCLE_1
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lr %r2,%r0 # return destination address
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br %r14
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END(__memcpy_mvcle)
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