[FFmpeg-devel] [PATCH] vp9: initial attempt at a idct_idct_4x4 12bpp x86 simd (sse2) impl.
Ronald S. Bultje
rsbultje at gmail.com
Tue Oct 6 21:59:50 CEST 2015
The trouble with this function is that intermediates overflow 31+sign
bits, so I've added some helpers (that will also be used in 10/12bpp
8x8, 16x16 and 32x32) to make that easier, basically emulating a half-
assed pmaddqd using 2xpmaddwd. It's currently sse2-only, if anyone sees
potential in adding ssse3, I'd love to hear it.
---
libavcodec/x86/vp9dsp_init_16bpp_template.c | 4 +
libavcodec/x86/vp9itxfm_16bpp.asm | 122 ++++++++++++++++++++++++++++
2 files changed, 126 insertions(+)
diff --git a/libavcodec/x86/vp9dsp_init_16bpp_template.c b/libavcodec/x86/vp9dsp_init_16bpp_template.c
index 93fc684..35f99b7 100644
--- a/libavcodec/x86/vp9dsp_init_16bpp_template.c
+++ b/libavcodec/x86/vp9dsp_init_16bpp_template.c
@@ -131,6 +131,8 @@ decl_itxfm_func(idct, iadst, 4, BPC, sse2);
decl_itxfm_func(iadst, idct, 4, BPC, sse2);
decl_itxfm_func(iadst, iadst, 4, BPC, sse2);
decl_itxfm_funcs(4, BPC, ssse3);
+#else
+decl_itxfm_func(idct, idct, 4, BPC, sse2);
#endif
#endif /* HAVE_YASM */
@@ -199,6 +201,8 @@ av_cold void INIT_FUNC(VP9DSPContext *dsp, int bitexact)
init_itx_func(TX_4X4, DCT_ADST, iadst, idct, 4, 10, sse2);
init_itx_func(TX_4X4, ADST_ADST, iadst, iadst, 4, 10, sse2);
}
+#else
+ init_itx_func(TX_4X4, DCT_DCT, idct, idct, 4, 12, sse2);
#endif
}
diff --git a/libavcodec/x86/vp9itxfm_16bpp.asm b/libavcodec/x86/vp9itxfm_16bpp.asm
index 11f080c..3621287 100644
--- a/libavcodec/x86/vp9itxfm_16bpp.asm
+++ b/libavcodec/x86/vp9itxfm_16bpp.asm
@@ -31,6 +31,9 @@ cextern pw_2048
cextern pw_4095
cextern pd_8192
+pd_8: times 4 dd 8
+pd_3fff: times 4 dd 0x3fff
+
; FIXME these should probably be shared between 8bpp and 10/12bpp
pw_m11585_11585: times 4 dw -11585, 11585
pw_11585_11585: times 8 dw 11585
@@ -273,3 +276,122 @@ INIT_MMX ssse3
IADST4_FN idct, IDCT4, iadst, IADST4
IADST4_FN iadst, IADST4, idct, IDCT4
IADST4_FN iadst, IADST4, iadst, IADST4
+
+; inputs and outputs are dwords, coefficients are words
+;
+; dst1 = src1 * coef1 + src2 * coef2 + rnd >> 14
+; dst2 = src1 * coef2 - src2 * coef1 + rnd >> 14
+%macro SUMSUB_MUL 6 ; src/dst 1-2, tmp1-2, coef1-2
+ pand m%3, m%1, [pd_3fff]
+ pand m%4, m%2, [pd_3fff]
+ psrad m%1, 14
+ psrad m%2, 14
+ packssdw m%4, m%2
+ packssdw m%3, m%1
+ punpckhwd m%2, m%4, m%3
+ punpcklwd m%4, m%3
+ pmaddwd m%3, m%4, [pw_%6_%5]
+ pmaddwd m%1, m%2, [pw_%6_%5]
+ pmaddwd m%4, [pw_m%5_%6]
+ pmaddwd m%2, [pw_m%5_%6]
+ paddd m%3, [pd_8192]
+ paddd m%4, [pd_8192]
+ psrad m%3, 14
+ psrad m%4, 14
+ paddd m%1, m%3
+ paddd m%2, m%4
+%endmacro
+
+%macro IDCT4_12BPP_1D 0
+ SUMSUB_MUL 0, 2, 4, 5, 11585, 11585
+ SUMSUB_MUL 1, 3, 4, 5, 15137, 6270
+ SUMSUB_BA d, 1, 0, 4
+ SUMSUB_BA d, 3, 2, 4
+ SWAP 1, 3, 0
+%endmacro
+
+INIT_XMM sse2
+cglobal vp9_idct_idct_4x4_add_12, 4, 4, 6, dst, stride, block, eob
+ cmp eobd, 1
+ jg .idctfull
+
+ ; dc-only - this is special, since for 4x4 12bpp, the max coef size is
+ ; 17+sign bpp. Since the multiply is with 11585, which is 14bpp, the
+ ; result of each multiply is 31+sign bit, i.e. it _exactly_ fits in a
+ ; dword. After the final shift (4), the result is 13+sign bits, so we
+ ; don't need any additional processing to fit it in a word
+ DEFINE_ARGS dst, stride, block, coef
+ mov coefd, dword [blockq]
+ imul coefd, 11585
+ add coefd, 8192
+ sar coefd, 14
+ imul coefd, 11585
+ add coefd, (8 << 14) + 8192
+ sar coefd, 14 + 4
+ movd m0, coefd
+ punpcklwd m0, m0
+ pshufd m0, m0, q0000
+ pxor m4, m4
+ mova m5, [pw_4095]
+ movd [blockq], m4
+ DEFINE_ARGS dst, stride, stride3
+ lea stride3q, [strideq*3]
+ movh m1, [dstq+strideq*0]
+ movh m3, [dstq+strideq*2]
+ movhps m1, [dstq+strideq*1]
+ movhps m3, [dstq+stride3q ]
+ paddw m1, m0
+ paddw m3, m0
+ pmaxsw m1, m4
+ pmaxsw m3, m4
+ pminsw m1, m5
+ pminsw m3, m5
+ movh [dstq+strideq*0], m1
+ movhps [dstq+strideq*1], m1
+ movh [dstq+strideq*2], m3
+ movhps [dstq+stride3q ], m3
+ RET
+
+.idctfull:
+ DEFINE_ARGS dst, stride, block, eob
+ mova m0, [blockq+0*16]
+ mova m1, [blockq+1*16]
+ mova m2, [blockq+2*16]
+ mova m3, [blockq+3*16]
+
+ IDCT4_12BPP_1D
+ TRANSPOSE4x4D 0, 1, 2, 3, 4
+ IDCT4_12BPP_1D
+
+ pxor m4, m4
+ ZERO_BLOCK blockq, 16, 4, m4
+
+ ; writeout
+ DEFINE_ARGS dst, stride, stride3
+ lea stride3q, [strideq*3]
+ paddd m0, [pd_8]
+ paddd m1, [pd_8]
+ paddd m2, [pd_8]
+ paddd m3, [pd_8]
+ psrad m0, 4
+ psrad m1, 4
+ psrad m2, 4
+ psrad m3, 4
+ packssdw m0, m1
+ packssdw m2, m3
+ mova m5, [pw_4095]
+ movh m1, [dstq+strideq*0]
+ movh m3, [dstq+strideq*2]
+ movhps m1, [dstq+strideq*1]
+ movhps m3, [dstq+stride3q ]
+ paddw m0, m1
+ paddw m2, m3
+ pmaxsw m0, m4
+ pmaxsw m2, m4
+ pminsw m0, m5
+ pminsw m2, m5
+ movh [dstq+strideq*0], m0
+ movhps [dstq+strideq*1], m0
+ movh [dstq+strideq*2], m2
+ movhps [dstq+stride3q ], m2
+ RET
--
2.1.2
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