118 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			118 lines
		
	
	
		
			4.0 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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| 
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| #include "config.h"
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| #include "asm.S"
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| 
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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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| 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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| 
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|         rsbs            r9, ip, r4, asr #16
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|         addgt           r9, r2, #0
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|         rsblt           r9, r2, #0
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|         smlatbne        r9, r4, r1, r9
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| 
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|         rsbs            lr, ip, r5, asr #16
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|         addgt           lr, r2, #0
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|         rsblt           lr, r2, #0
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|         smlatbne        lr, r5, r1, lr
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| 
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|         rsbs            r8, ip, r4, asl #16
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|         addgt           r8, r2, #0
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|         rsblt           r8, r2, #0
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|         smlabbne        r4, r4, r1, r8
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| 
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|         rsbs            r8, ip, r5, asl #16
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|         addgt           r8, r2, #0
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|         rsblt           r8, r2, #0
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|         smlabbne        r5, r5, r1, r8
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| 
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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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| 
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|         rsbs            r9, ip, r6, asr #16
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|         addgt           r9, r2, #0
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|         rsblt           r9, r2, #0
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|         smlatbne        r9, r6, r1, r9
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| 
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|         rsbs            lr, ip, r7, asr #16
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|         addgt           lr, r2, #0
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|         rsblt           lr, r2, #0
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|         smlatbne        lr, r7, r1, lr
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| 
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|         rsbs            r8, ip, r6, asl #16
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|         addgt           r8, r2, #0
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|         rsblt           r8, r2, #0
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|         smlabbne        r6, r6, r1, r8
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| 
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|         rsbs            r8, ip, r7, asl #16
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|         addgt           r8, r2, #0
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|         rsblt           r8, r2, #0
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|         smlabbne        r7, r7, r1, r8
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| 
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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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| 
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|         subs            r3, r3, #8
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|         ldrgtd          r4, [r0, #0] /* load data early to avoid load/use pipeline stall */
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|         bgt             1b
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| 
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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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