From 29eb1c51d7352c55990ba938194d91486f460d2d Mon Sep 17 00:00:00 2001 From: Rostislav Pehlivanov Date: Mon, 7 May 2018 23:16:37 +0100 Subject: mdct15: simplify x86 exptab permutation Removes an unneeded copy and does the 5-point permute in-place. Signed-off-by: Rostislav Pehlivanov --- libavcodec/x86/mdct15_init.c | 53 ++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 29 deletions(-) (limited to 'libavcodec/x86') diff --git a/libavcodec/x86/mdct15_init.c b/libavcodec/x86/mdct15_init.c index 45b91b7e21..444801d9cf 100644 --- a/libavcodec/x86/mdct15_init.c +++ b/libavcodec/x86/mdct15_init.c @@ -33,32 +33,35 @@ void ff_fft15_avx(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t static void perm_twiddles(MDCT15Context *s) { int k; - FFTComplex exp_5point[4]; + FFTComplex tmp[30]; - FFTComplex tmp[21], tmp2[30]; - memcpy(tmp, s->exptab, sizeof(FFTComplex)*21); + /* 5-point FFT twiddles */ + s->exptab[60].re = s->exptab[60].im = s->exptab[19].re; + s->exptab[61].re = s->exptab[61].im = s->exptab[19].im; + s->exptab[62].re = s->exptab[62].im = s->exptab[20].re; + s->exptab[63].re = s->exptab[63].im = s->exptab[20].im; /* 15-point FFT twiddles */ for (k = 0; k < 5; k++) { - tmp2[6*k + 0] = tmp[k + 0]; - tmp2[6*k + 2] = tmp[k + 5]; - tmp2[6*k + 4] = tmp[k + 10]; + tmp[6*k + 0] = s->exptab[k + 0]; + tmp[6*k + 2] = s->exptab[k + 5]; + tmp[6*k + 4] = s->exptab[k + 10]; - tmp2[6*k + 1] = tmp[2 * (k + 0)]; - tmp2[6*k + 3] = tmp[2 * (k + 5)]; - tmp2[6*k + 5] = tmp[2 * k + 5 ]; + tmp[6*k + 1] = s->exptab[2 * (k + 0)]; + tmp[6*k + 3] = s->exptab[2 * (k + 5)]; + tmp[6*k + 5] = s->exptab[2 * k + 5 ]; } for (k = 0; k < 6; k++) { FFTComplex ac_exp[] = { - { tmp2[6*1 + k].re, tmp2[6*1 + k].re }, - { tmp2[6*2 + k].re, tmp2[6*2 + k].re }, - { tmp2[6*3 + k].re, tmp2[6*3 + k].re }, - { tmp2[6*4 + k].re, tmp2[6*4 + k].re }, - { tmp2[6*1 + k].im, -tmp2[6*1 + k].im }, - { tmp2[6*2 + k].im, -tmp2[6*2 + k].im }, - { tmp2[6*3 + k].im, -tmp2[6*3 + k].im }, - { tmp2[6*4 + k].im, -tmp2[6*4 + k].im }, + { tmp[6*1 + k].re, tmp[6*1 + k].re }, + { tmp[6*2 + k].re, tmp[6*2 + k].re }, + { tmp[6*3 + k].re, tmp[6*3 + k].re }, + { tmp[6*4 + k].re, tmp[6*4 + k].re }, + { tmp[6*1 + k].im, -tmp[6*1 + k].im }, + { tmp[6*2 + k].im, -tmp[6*2 + k].im }, + { tmp[6*3 + k].im, -tmp[6*3 + k].im }, + { tmp[6*4 + k].im, -tmp[6*4 + k].im }, }; memcpy(s->exptab + 8*k, ac_exp, 8*sizeof(FFTComplex)); } @@ -66,21 +69,13 @@ static void perm_twiddles(MDCT15Context *s) /* Specialcase when k = 0 */ for (k = 0; k < 3; k++) { FFTComplex dc_exp[] = { - { tmp2[2*k + 0].re, -tmp2[2*k + 0].im }, - { tmp2[2*k + 0].im, tmp2[2*k + 0].re }, - { tmp2[2*k + 1].re, -tmp2[2*k + 1].im }, - { tmp2[2*k + 1].im, tmp2[2*k + 1].re }, + { tmp[2*k + 0].re, -tmp[2*k + 0].im }, + { tmp[2*k + 0].im, tmp[2*k + 0].re }, + { tmp[2*k + 1].re, -tmp[2*k + 1].im }, + { tmp[2*k + 1].im, tmp[2*k + 1].re }, }; memcpy(s->exptab + 8*6 + 4*k, dc_exp, 4*sizeof(FFTComplex)); } - - /* 5-point FFT twiddles */ - exp_5point[0].re = exp_5point[0].im = tmp[19].re; - exp_5point[1].re = exp_5point[1].im = tmp[19].im; - exp_5point[2].re = exp_5point[2].im = tmp[20].re; - exp_5point[3].re = exp_5point[3].im = tmp[20].im; - - memcpy(s->exptab + 8*6 + 4*3, exp_5point, 4*sizeof(FFTComplex)); } av_cold void ff_mdct15_init_x86(MDCT15Context *s) -- cgit v1.2.3