mirror of https://git.ffmpeg.org/ffmpeg.git
103 lines
3.5 KiB
ArmAsm
103 lines
3.5 KiB
ArmAsm
/*
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* Optimization of some functions from mpegvideo.c for armv5te
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* Copyright (c) 2007 Siarhei Siamashka <ssvb@users.sourceforge.net>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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*
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* FFmpeg 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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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "config.h"
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#include "asm.S"
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/*
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* Special optimized version of dct_unquantize_h263_helper_c, it
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* requires the block to be at least 8 bytes aligned, and may process
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* more elements than requested. But it is guaranteed to never
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* process more than 64 elements provided that count argument is <= 64,
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* so it is safe. This function is optimized for a common distribution
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* of values for nCoeffs (they are mostly multiple of 8 plus one or
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* two extra elements). So this function processes data as 8 elements
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* per loop iteration and contains optional 2 elements processing in
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* the end.
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*
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* Inner loop should take 6 cycles per element on arm926ej-s (Nokia 770)
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*/
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.macro dequant_t dst, src, mul, add, tmp
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rsbs \tmp, ip, \src, asr #16
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addgt \tmp, \add, #0
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rsblt \tmp, \add, #0
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smlatbne \dst, \src, \mul, \tmp
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.endm
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.macro dequant_b dst, src, mul, add, tmp
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rsbs \tmp, ip, \src, lsl #16
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addgt \tmp, \add, #0
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rsblt \tmp, \add, #0
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smlabbne \dst, \src, \mul, \tmp
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.endm
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function ff_dct_unquantize_h263_armv5te, export=1
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push {r4-r9,lr}
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mov ip, #0
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subs r3, r3, #2
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ble 2f
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ldrd r4, [r0, #0]
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1:
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ldrd r6, [r0, #8]
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dequant_t r9, r4, r1, r2, r9
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dequant_t lr, r5, r1, r2, lr
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dequant_b r4, r4, r1, r2, r8
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dequant_b r5, r5, r1, r2, r8
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strh r4, [r0], #2
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strh r9, [r0], #2
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strh r5, [r0], #2
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strh lr, [r0], #2
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dequant_t r9, r6, r1, r2, r9
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dequant_t lr, r7, r1, r2, lr
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dequant_b r6, r6, r1, r2, r8
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dequant_b r7, r7, r1, r2, r8
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strh r6, [r0], #2
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strh r9, [r0], #2
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strh r7, [r0], #2
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strh lr, [r0], #2
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subs r3, r3, #8
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ldrdgt r4, [r0, #0] /* load data early to avoid load/use pipeline stall */
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bgt 1b
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adds r3, r3, #2
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pople {r4-r9,pc}
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2:
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ldrsh r9, [r0, #0]
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ldrsh lr, [r0, #2]
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mov r8, r2
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cmp r9, #0
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rsblt r8, r2, #0
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smlabbne r9, r9, r1, r8
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mov r8, r2
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cmp lr, #0
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rsblt r8, r2, #0
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smlabbne lr, lr, r1, r8
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strh r9, [r0], #2
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strh lr, [r0], #2
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pop {r4-r9,pc}
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endfunc
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