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FFmpeg/libavcodec/x86/fmtconvert.asm
Janne Grunau 8563f98871 x86: use emms after ff_int32_to_float_fmul_scalar_sse
Intel's Instruction Set Reference (as of September 2015) clearly states
that cvtpi2ps switches to MMX state. Actual CPUs do not switch if the
source is a memory location. The Instruction Set Reference from 1999
(Order Number 243191) describes this behaviour but all later versions
I've seen have make no distinction whether MMX registers or memory is
used as source.
The documentation for the matching SSE2 instruction to convert to double
(cvtpi2pd) was fixed (see the valgrind bug
https://bugs.kde.org/show_bug.cgi?id=210264).

It will take time to get a clarification and fixes in place. In the
meantime it makes sense to change ff_int32_to_float_fmul_scalar_sse to
be correct according to the documentation. The vast majority of users
will have SSE2 so a change to the SSE version has little effect.

Fixes fate-checkasm on x86 valgrind targets.

Valgrind 'bug' reported as https://bugs.kde.org/show_bug.cgi?id=357059
2015-12-30 13:37:57 +01:00

78 lines
2.4 KiB
NASM

;******************************************************************************
;* x86 optimized Format Conversion Utils
;* Copyright (c) 2008 Loren Merritt
;*
;* This file is part of Libav.
;*
;* Libav 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.
;*
;* Libav 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 Libav; if not, write to the Free Software
;* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;******************************************************************************
%include "libavutil/x86/x86util.asm"
SECTION .text
;------------------------------------------------------------------------------
; void ff_int32_to_float_fmul_scalar(float *dst, const int32_t *src, float mul,
; int len);
;------------------------------------------------------------------------------
%macro INT32_TO_FLOAT_FMUL_SCALAR 1
%if UNIX64
cglobal int32_to_float_fmul_scalar, 3, 3, %1, dst, src, len
%else
cglobal int32_to_float_fmul_scalar, 4, 4, %1, dst, src, mul, len
%endif
%if WIN64
SWAP 0, 2
%elif ARCH_X86_32
movss m0, mulm
%endif
SPLATD m0
shl lend, 2
add srcq, lenq
add dstq, lenq
neg lenq
.loop:
%if cpuflag(sse2)
cvtdq2ps m1, [srcq+lenq ]
cvtdq2ps m2, [srcq+lenq+16]
%else
cvtpi2ps m1, [srcq+lenq ]
cvtpi2ps m3, [srcq+lenq+ 8]
cvtpi2ps m2, [srcq+lenq+16]
cvtpi2ps m4, [srcq+lenq+24]
movlhps m1, m3
movlhps m2, m4
%endif
mulps m1, m0
mulps m2, m0
mova [dstq+lenq ], m1
mova [dstq+lenq+16], m2
add lenq, 32
jl .loop
%if notcpuflag(sse2)
;; cvtpi2ps switches to MMX even if the source is a memory location
;; possible an error in documentation since every tested CPU disagrees with
;; that. Use emms anyway since the vast majority of machines will use the
;; SSE2 variant
emms
%endif
RET
%endmacro
INIT_XMM sse
INT32_TO_FLOAT_FMUL_SCALAR 5
INIT_XMM sse2
INT32_TO_FLOAT_FMUL_SCALAR 3