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	armv6: Accelerate butterflies_float
I benchmarked the result by measuring the number of gperftools samples that
hit anywhere in the AAC decoder (starting from aac_decode_frame()) or
specifically in butterflies_float_c() / ff_butterflies_float_vfp() for the
same sample AAC stream:
                   Before          After
                   Mean   StdDev   Mean   StdDev  Confidence  Change
Audio decode       1542.8 43.7     1470.5 41.5    100.0%      +4.9%
butterflies_float  130.0  11.9     70.2   12.1    100.0%      +85.2%
Signed-off-by: Martin Storsjö <martin@martin.st>
			
			
This commit is contained in:
		
				
					committed by
					
						 Martin Storsjö
						Martin Storsjö
					
				
			
			
				
	
			
			
			
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							5edad2c4a1
						
					
				
				
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					5a272190a0
				
			| @@ -32,6 +32,8 @@ void ff_vector_fmul_window_vfp(float *dst, const float *src0, | ||||
| void ff_vector_fmul_reverse_vfp(float *dst, const float *src0, | ||||
|                                 const float *src1, int len); | ||||
|  | ||||
| void ff_butterflies_float_vfp(float *restrict v1, float *restrict v2, int len); | ||||
|  | ||||
| av_cold void ff_float_dsp_init_vfp(AVFloatDSPContext *fdsp, int cpu_flags) | ||||
| { | ||||
|     if (!have_vfpv3(cpu_flags)) { | ||||
| @@ -39,4 +41,6 @@ av_cold void ff_float_dsp_init_vfp(AVFloatDSPContext *fdsp, int cpu_flags) | ||||
|         fdsp->vector_fmul_window = ff_vector_fmul_window_vfp; | ||||
|     } | ||||
|     fdsp->vector_fmul_reverse = ff_vector_fmul_reverse_vfp; | ||||
|     if (!have_vfpv3(cpu_flags)) | ||||
|         fdsp->butterflies_float = ff_butterflies_float_vfp; | ||||
| } | ||||
|   | ||||
| @@ -339,3 +339,119 @@ function ff_vector_fmul_reverse_vfp, export=1 | ||||
|         vpop            {d8-d15} | ||||
|         bx              lr | ||||
| endfunc | ||||
|  | ||||
| /** | ||||
|  * ARM VFP implementation of 'butterflies_float_c' function | ||||
|  * Assume that len is a positive non-zero number | ||||
|  */ | ||||
| @ void ff_butterflies_float_vfp(float *restrict v1, float *restrict v2, int len) | ||||
| function ff_butterflies_float_vfp, export=1 | ||||
| BASE1   .req    a1 | ||||
| BASE2   .req    a2 | ||||
| LEN     .req    a3 | ||||
| OLDFPSCR .req   a4 | ||||
|  | ||||
|         vpush   {s16-s31} | ||||
|         fmrx    OLDFPSCR, FPSCR | ||||
|  | ||||
|         tst     LEN, #7 | ||||
|         beq     4f                          @ common case: len is a multiple of 8 | ||||
|  | ||||
|         ldr     ip, =0x03000000             @ RunFast mode, scalar mode | ||||
|         fmxr    FPSCR, ip | ||||
|  | ||||
|         tst     LEN, #1 | ||||
|         beq     1f | ||||
|         vldmia  BASE1!, {s0} | ||||
|         vldmia  BASE2!, {s8} | ||||
|         vadd.f  s16, s0, s8 | ||||
|         vsub.f  s24, s0, s8 | ||||
|         vstr    s16, [BASE1, #0-4*1] | ||||
|         vstr    s24, [BASE2, #0-4*1] | ||||
| 1: | ||||
|         tst     LEN, #2 | ||||
|         beq     2f | ||||
|         vldmia  BASE1!, {s0-s1} | ||||
|         vldmia  BASE2!, {s8-s9} | ||||
|         vadd.f  s16, s0, s8 | ||||
|         vadd.f  s17, s1, s9 | ||||
|         vsub.f  s24, s0, s8 | ||||
|         vsub.f  s25, s1, s9 | ||||
|         vstr    d8, [BASE1, #0-8*1]    @ s16,s17 | ||||
|         vstr    d12, [BASE2, #0-8*1]   @ s24,s25 | ||||
| 2: | ||||
|         tst     LEN, #4 | ||||
|         beq     3f | ||||
|         vldmia  BASE1!, {s0-s1} | ||||
|         vldmia  BASE2!, {s8-s9} | ||||
|         vldmia  BASE1!, {s2-s3} | ||||
|         vldmia  BASE2!, {s10-s11} | ||||
|         vadd.f  s16, s0, s8 | ||||
|         vadd.f  s17, s1, s9 | ||||
|         vsub.f  s24, s0, s8 | ||||
|         vsub.f  s25, s1, s9 | ||||
|         vadd.f  s18, s2, s10 | ||||
|         vadd.f  s19, s3, s11 | ||||
|         vsub.f  s26, s2, s10 | ||||
|         vsub.f  s27, s3, s11 | ||||
|         vstr    d8, [BASE1, #0-16*1]    @ s16,s17 | ||||
|         vstr    d12, [BASE2, #0-16*1]   @ s24,s25 | ||||
|         vstr    d9, [BASE1, #8-16*1]    @ s18,s19 | ||||
|         vstr    d13, [BASE2, #8-16*1]   @ s26,s27 | ||||
| 3: | ||||
|         bics    LEN, LEN, #7 | ||||
|         beq     7f | ||||
| 4: | ||||
|         ldr     ip, =0x03030000             @ RunFast mode, short vectors of length 4, stride 1 | ||||
|         fmxr    FPSCR, ip | ||||
|  | ||||
|         vldmia  BASE1!, {s0-s1} | ||||
|         vldmia  BASE2!, {s8-s9} | ||||
|         vldmia  BASE1!, {s2-s3} | ||||
|         vldmia  BASE2!, {s10-s11} | ||||
|         vadd.f  s16, s0, s8 | ||||
|             vldmia  BASE1!, {s4-s5} | ||||
|             vldmia  BASE2!, {s12-s13} | ||||
|             vldmia  BASE1!, {s6-s7} | ||||
|             vldmia  BASE2!, {s14-s15} | ||||
|         vsub.f  s24, s0, s8 | ||||
|             vadd.f  s20, s4, s12 | ||||
|         subs    LEN, LEN, #8 | ||||
|         beq     6f | ||||
| 5:              vldmia  BASE1!, {s0-s3} | ||||
|                 vldmia  BASE2!, {s8-s11} | ||||
|             vsub.f  s28, s4, s12 | ||||
|         vstr    d8, [BASE1, #0-16*3]    @ s16,s17 | ||||
|         vstr    d9, [BASE1, #8-16*3]    @ s18,s19 | ||||
|         vstr    d12, [BASE2, #0-16*3]   @ s24,s25 | ||||
|         vstr    d13, [BASE2, #8-16*3]   @ s26,s27 | ||||
|                 vadd.f  s16, s0, s8 | ||||
|                     vldmia  BASE1!, {s4-s7} | ||||
|                     vldmia  BASE2!, {s12-s15} | ||||
|                 vsub.f  s24, s0, s8 | ||||
|             vstr    d10, [BASE1, #0-16*3]   @ s20,s21 | ||||
|             vstr    d11, [BASE1, #8-16*3]   @ s22,s23 | ||||
|             vstr    d14, [BASE2, #0-16*3]   @ s28,s29 | ||||
|             vstr    d15, [BASE2, #8-16*3]   @ s30,s31 | ||||
|                     vadd.f  s20, s4, s12 | ||||
|         subs    LEN, LEN, #8 | ||||
|         bne     5b | ||||
| 6:                   vsub.f  s28, s4, s12 | ||||
|                 vstr    d8, [BASE1, #0-16*2]    @ s16,s17 | ||||
|                 vstr    d9, [BASE1, #8-16*2]    @ s18,s19 | ||||
|                 vstr    d12, [BASE2, #0-16*2]   @ s24,s25 | ||||
|                 vstr    d13, [BASE2, #8-16*2]   @ s26,s27 | ||||
|                     vstr    d10, [BASE1, #0-16*1]   @ s20,s21 | ||||
|                     vstr    d11, [BASE1, #8-16*1]   @ s22,s23 | ||||
|                     vstr    d14, [BASE2, #0-16*1]   @ s28,s29 | ||||
|                     vstr    d15, [BASE2, #8-16*1]   @ s30,s31 | ||||
| 7: | ||||
|         fmxr    FPSCR, OLDFPSCR | ||||
|         vpop    {s16-s31} | ||||
|         bx      lr | ||||
|  | ||||
|         .unreq  BASE1 | ||||
|         .unreq  BASE2 | ||||
|         .unreq  LEN | ||||
|         .unreq  OLDFPSCR | ||||
| endfunc | ||||
|   | ||||
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