[FFmpeg-cvslog] lavc/h264dsp: use saturing add/sub for R-V V 8-bit DC add
Rémi Denis-Courmont
git at videolan.org
Sun Jul 28 21:24:19 EEST 2024
ffmpeg | branch: master | Rémi Denis-Courmont <remi at remlab.net> | Thu Jul 25 20:47:34 2024 +0300| [b0b3bea10bab54f22f976245da343fb42c9c1f28] | committer: Rémi Denis-Courmont
lavc/h264dsp: use saturing add/sub for R-V V 8-bit DC add
T-Head C908 (cycles):
h264_idct4_dc_add_8bpp_c: 109.2
h264_idct4_dc_add_8bpp_rvv_i32: 34.5 (before)
h264_idct4_dc_add_8bpp_rvv_i32: 25.5 (after)
h264_idct8_dc_add_8bpp_c: 418.7
h264_idct8_dc_add_8bpp_rvv_i64: 69.5 (before)
h264_idct8_dc_add_8bpp_rvv_i64: 33.5 (after)
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b0b3bea10bab54f22f976245da343fb42c9c1f28
---
libavcodec/riscv/h264dsp_init.c | 5 +++--
libavcodec/riscv/h264idct_rvv.S | 28 ++++++++++++++++++----------
2 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/libavcodec/riscv/h264dsp_init.c b/libavcodec/riscv/h264dsp_init.c
index 836c073559..671330d664 100644
--- a/libavcodec/riscv/h264dsp_init.c
+++ b/libavcodec/riscv/h264dsp_init.c
@@ -98,8 +98,8 @@ av_cold void ff_h264dsp_init_riscv(H264DSPContext *dsp, const int bit_depth,
dsp->h264_idct_add = ff_h264_idct_add_8_rvv;
dsp->h264_idct8_add = ff_h264_idct8_add_8_rvv;
- dsp->h264_idct_dc_add = ff_h264_idct4_dc_add_8_rvv;
if (flags & AV_CPU_FLAG_RVB) {
+ dsp->h264_idct_dc_add = ff_h264_idct4_dc_add_8_rvv;
dsp->h264_idct_add16 = ff_h264_idct_add16_8_rvv;
dsp->h264_idct_add16intra = ff_h264_idct_add16intra_8_rvv;
# if __riscv_xlen == 64
@@ -108,7 +108,8 @@ av_cold void ff_h264dsp_init_riscv(H264DSPContext *dsp, const int bit_depth,
}
if (flags & AV_CPU_FLAG_RVV_I64) {
dsp->h264_add_pixels8_clear = ff_h264_add_pixels8_8_rvv;
- dsp->h264_idct8_dc_add = ff_h264_idct8_dc_add_8_rvv;
+ if (flags & AV_CPU_FLAG_RVB)
+ dsp->h264_idct8_dc_add = ff_h264_idct8_dc_add_8_rvv;
}
dsp->h264_add_pixels4_clear = ff_h264_add_pixels4_8_rvv;
}
diff --git a/libavcodec/riscv/h264idct_rvv.S b/libavcodec/riscv/h264idct_rvv.S
index 5dd92de77d..f823346c8d 100644
--- a/libavcodec/riscv/h264idct_rvv.S
+++ b/libavcodec/riscv/h264idct_rvv.S
@@ -420,7 +420,7 @@ endfunc
.endr
.macro idct_dc_add8 width
-func ff_h264_idct\width\()_dc_add_8_rvv, zve64x
+func ff_h264_idct\width\()_dc_add_8_rvv, zve64x, b
lpad 0
.if \width == 8
vsetivli zero, \width, e8, mf2, ta, ma
@@ -428,26 +428,34 @@ func ff_h264_idct\width\()_dc_add_8_rvv, zve64x
vsetivli zero, \width, e8, mf4, ta, ma
.endif
lh t0, 0(a1)
+ li t1, 255
addi t0, t0, 32
srai t0, t0, 6
sh zero, 0(a1)
.if \width == 8
li a6, \width * \width
vlse64.v v24, (a0), a2
- vsetvli zero, a6, e16, m8, ta, ma
+ vsetvli zero, a6, e8, m4, ta, ma
.else
vlse32.v v24, (a0), a2
- vsetivli zero, \width * \width, e16, m2, ta, ma
+ vsetivli zero, \width * \width, e8, m1, ta, ma
.endif
- vzext.vf2 v0, v24
- vadd.vx v0, v0, t0
- vmax.vx v0, v0, zero
-.if \width == 8
- vsetvli zero, zero, e8, m4, ta, ma
+ bgez t0, 1f
+
+ neg t0, t0
+ minu t0, t0, t1
+ vssubu.vx v24, v24, t0
+ .if \width == 8
+ vsetivli zero, \width, e8, mf2, ta, ma
+ vsse64.v v24, (a0), a2
.else
- vsetvli zero, zero, e8, m1, ta, ma
+ vsetivli zero, \width, e8, mf4, ta, ma
+ vsse32.v v24, (a0), a2
.endif
- vnclipu.wi v24, v0, 0
+ ret
+1:
+ minu t0, t0, t1
+ vsaddu.vx v24, v24, t0
.if \width == 8
vsetivli zero, \width, e8, mf2, ta, ma
vsse64.v v24, (a0), a2
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