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arm: Add VFP-accelerated version of int32_to_float_fmul_array8

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Before           After
               Mean    StdDev   Mean    StdDev  Change
This function    366.2  18.3      277.8  13.7   +31.9%
Overall        18420.5 489.1    17049.5 408.2    +8.0%

Signed-off-by: Martin Storsjö <martin@martin.st>
pull/27/merge
Ben Avison 12 years ago committed by Martin Storsjö
parent 26ffcc7de1
commit d6e4f5fef0
2 changed files with 167 additions and 1 deletions
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  1. 6
      libavcodec/arm/fmtconvert_init_arm.c
  2. 162
      libavcodec/arm/fmtconvert_vfp.S

6
libavcodec/arm/fmtconvert_init_arm.c
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@ -30,6 +30,9 @@ void ff_int32_to_float_fmul_scalar_neon(float *dst, const int32_t *src,
void ff_int32_to_float_fmul_scalar_vfp(float *dst, const int32_t *src,
float mul, int len);
void ff_int32_to_float_fmul_array8_vfp(FmtConvertContext *c, float *dst,
const int32_t *src, const float *mul,
int len);
void ff_float_to_int16_neon(int16_t *dst, const float *src, long len);
void ff_float_to_int16_interleave_neon(int16_t *, const float **, long, int);
@ -42,10 +45,11 @@ av_cold void ff_fmt_convert_init_arm(FmtConvertContext *c, AVCodecContext *avctx
if (have_vfp(cpu_flags) && have_armv6(cpu_flags)) {
if (!have_vfpv3(cpu_flags)) {
// This function doesn't use anything armv6 specific in itself,
// These functions don't use anything armv6 specific in themselves,
// but ff_float_to_int16_vfp which is in the same assembly source
// file does, thus the whole file requires armv6 to be built.
c->int32_to_float_fmul_scalar = ff_int32_to_float_fmul_scalar_vfp;
c->int32_to_float_fmul_array8 = ff_int32_to_float_fmul_array8_vfp;
}
c->float_to_int16 = ff_float_to_int16_vfp;

162
libavcodec/arm/fmtconvert_vfp.S
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@ -83,6 +83,168 @@ endfunc
* Assume len is a multiple of 8, destination buffer is at least 4 bytes aligned
* (16 bytes alignment is best for BCM2835), little-endian.
*/
@ void ff_int32_to_float_fmul_array8_vfp(FmtConvertContext *c, float *dst, const int32_t *src, const float *mul, int len)
function ff_int32_to_float_fmul_array8_vfp, export=1
push {lr}
ldr a1, [sp, #4]
subs lr, a1, #3*8
bcc 50f @ too short to pipeline
@ Now need to find (len / 8) % 3. The approximation
@ x / 24 = (x * 0xAB) >> 12
@ is good for x < 4096, which is true for both AC3 and DCA.
mov a1, #0xAB
ldr ip, =0x03070000 @ RunFast mode, short vectors of length 8, stride 1
mul a1, lr, a1
vpush {s16-s31}
mov a1, a1, lsr #12
add a1, a1, a1, lsl #1
rsb a1, a1, lr, lsr #3
cmp a1, #1
fmrx a1, FPSCR
fmxr FPSCR, ip
beq 11f
blo 10f
@ Array is (2 + multiple of 3) x 8 floats long
@ drop through...
vldmia a3!, {s16-s23}
vldmia a4!, {s2,s3}
vldmia a3!, {s24-s31}
vcvt.f32.s32 s16, s16
vcvt.f32.s32 s17, s17
vcvt.f32.s32 s18, s18
vcvt.f32.s32 s19, s19
vcvt.f32.s32 s20, s20
vcvt.f32.s32 s21, s21
vcvt.f32.s32 s22, s22
vcvt.f32.s32 s23, s23
vmul.f32 s16, s16, s2
@ drop through...
3:
vldmia a3!, {s8-s15}
vldmia a4!, {s1}
vcvt.f32.s32 s24, s24
vcvt.f32.s32 s25, s25
vcvt.f32.s32 s26, s26
vcvt.f32.s32 s27, s27
vcvt.f32.s32 s28, s28
vcvt.f32.s32 s29, s29
vcvt.f32.s32 s30, s30
vcvt.f32.s32 s31, s31
vmul.f32 s24, s24, s3
vstmia a2!, {s16-s19}
vstmia a2!, {s20-s23}
2:
vldmia a3!, {s16-s23}
vldmia a4!, {s2}
vcvt.f32.s32 s8, s8
vcvt.f32.s32 s9, s9
vcvt.f32.s32 s10, s10
vcvt.f32.s32 s11, s11
vcvt.f32.s32 s12, s12
vcvt.f32.s32 s13, s13
vcvt.f32.s32 s14, s14
vcvt.f32.s32 s15, s15
vmul.f32 s8, s8, s1
vstmia a2!, {s24-s27}
vstmia a2!, {s28-s31}
1:
vldmia a3!, {s24-s31}
vldmia a4!, {s3}
vcvt.f32.s32 s16, s16
vcvt.f32.s32 s17, s17
vcvt.f32.s32 s18, s18
vcvt.f32.s32 s19, s19
vcvt.f32.s32 s20, s20
vcvt.f32.s32 s21, s21
vcvt.f32.s32 s22, s22
vcvt.f32.s32 s23, s23
vmul.f32 s16, s16, s2
vstmia a2!, {s8-s11}
vstmia a2!, {s12-s15}
subs lr, lr, #8*3
bpl 3b
vcvt.f32.s32 s24, s24
vcvt.f32.s32 s25, s25
vcvt.f32.s32 s26, s26
vcvt.f32.s32 s27, s27
vcvt.f32.s32 s28, s28
vcvt.f32.s32 s29, s29
vcvt.f32.s32 s30, s30
vcvt.f32.s32 s31, s31
vmul.f32 s24, s24, s3
vstmia a2!, {s16-s19}
vstmia a2!, {s20-s23}
vstmia a2!, {s24-s27}
vstmia a2!, {s28-s31}
fmxr FPSCR, a1
vpop {s16-s31}
pop {pc}
10: @ Array is (multiple of 3) x 8 floats long
vldmia a3!, {s8-s15}
vldmia a4!, {s1,s2}
vldmia a3!, {s16-s23}
vcvt.f32.s32 s8, s8
vcvt.f32.s32 s9, s9
vcvt.f32.s32 s10, s10
vcvt.f32.s32 s11, s11
vcvt.f32.s32 s12, s12
vcvt.f32.s32 s13, s13
vcvt.f32.s32 s14, s14
vcvt.f32.s32 s15, s15
vmul.f32 s8, s8, s1
b 1b
11: @ Array is (1 + multiple of 3) x 8 floats long
vldmia a3!, {s24-s31}
vldmia a4!, {s3}
vldmia a3!, {s8-s15}
vldmia a4!, {s1}
vcvt.f32.s32 s24, s24
vcvt.f32.s32 s25, s25
vcvt.f32.s32 s26, s26
vcvt.f32.s32 s27, s27
vcvt.f32.s32 s28, s28
vcvt.f32.s32 s29, s29
vcvt.f32.s32 s30, s30
vcvt.f32.s32 s31, s31
vmul.f32 s24, s24, s3
b 2b
50:
ldr lr, =0x03070000 @ RunFast mode, short vectors of length 8, stride 1
fmrx ip, FPSCR
fmxr FPSCR, lr
51:
vldmia a3!, {s8-s15}
vldmia a4!, {s0}
vcvt.f32.s32 s8, s8
vcvt.f32.s32 s9, s9
vcvt.f32.s32 s10, s10
vcvt.f32.s32 s11, s11
vcvt.f32.s32 s12, s12
vcvt.f32.s32 s13, s13
vcvt.f32.s32 s14, s14
vcvt.f32.s32 s15, s15
vmul.f32 s8, s8, s0
subs a1, a1, #8
vstmia a2!, {s8-s11}
vstmia a2!, {s12-s15}
bne 51b
fmxr FPSCR, ip
pop {pc}
endfunc
/**
* ARM VFP optimised int32 to float conversion.
* Assume len is a multiple of 8, destination buffer is at least 4 bytes aligned
* (16 bytes alignment is best for BCM2835), little-endian.
* TODO: could be further optimised by unrolling and interleaving, as above
*/
@ void ff_int32_to_float_fmul_scalar_vfp(float *dst, const int32_t *src, float mul, int len)
function ff_int32_to_float_fmul_scalar_vfp, export=1
VFP tmp .req a4

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