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armv6: Accelerate butterflies_float

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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>
pull/77/merge
Ben Avison 10 years ago committed by Martin Storsjö
parent 5edad2c4a1
commit 5a272190a0
2 changed files with 120 additions and 0 deletions
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  1. 4
      libavutil/arm/float_dsp_init_vfp.c
  2. 116
      libavutil/arm/float_dsp_vfp.S

4
libavutil/arm/float_dsp_init_vfp.c
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@ -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;
}

116
libavutil/arm/float_dsp_vfp.S
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@ -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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