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Streamline x86 u8 -> fixed15 math.

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We can use SSE's 16 bit mul-hi to get a very good approximation to the
ideal multiplier.  This lets us trim several instructions.

This removes the need for the constant 0x0001 and instead uses 0x8081.
I've reordered the constants so that 0x8000 comes first, which helps
trim an instruction here and there on ARM.

Change-Id: I3d490c802df39a89424230c4cfc491f52210c275
Reviewed-on: https://skia-review.googlesource.com/7282
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
This commit is contained in:
Mike Klein 2017-01-20 00:04:58 -05:00 committed by Skia Commit-Bot
parent c37e61455d
commit f61bc4d229
4 changed files with 30 additions and 56 deletions
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2
src/splicer/SkSplicer.cpp
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@ -44,7 +44,7 @@ namespace {
12.46f, 0.411192f, 0.689206f, -0.0988f, 0.0043f, // to_srgb
};
static const SkSplicer_constants_lowp kConstants_lowp = {
0x0001, 0x8000,
0x8000, 0x8081,
};
// We do this a lot, so it's nice to infer the correct size. Works fine with arrays.

76
src/splicer/SkSplicer_generated_lowp.h
View File

@ -29,8 +29,7 @@ static const unsigned int kSplice_plus__lowp[] = {
0x6e670c63, // uqadd v3.8h, v3.8h, v7.8h
};
static const unsigned int kSplice_srcover_lowp[] = {
0x91000868, // add x8, x3, #0x2
0x4d40c510, // ld1r {v16.8h}, [x8]
0x4d40c470, // ld1r {v16.8h}, [x3]
0x6e632e10, // uqsub v16.8h, v16.8h, v3.8h
0x6e70b491, // sqrdmulh v17.8h, v4.8h, v16.8h
0x4e241e12, // and v18.16b, v16.16b, v4.16b
@ -54,8 +53,7 @@ static const unsigned int kSplice_srcover_lowp[] = {
0x6e630e83, // uqadd v3.8h, v20.8h, v3.8h
};
static const unsigned int kSplice_dstover_lowp[] = {
0x91000868, // add x8, x3, #0x2
0x4d40c510, // ld1r {v16.8h}, [x8]
0x4d40c470, // ld1r {v16.8h}, [x3]
0x6e672e10, // uqsub v16.8h, v16.8h, v7.8h
0x6e70b411, // sqrdmulh v17.8h, v0.8h, v16.8h
0x4e201e12, // and v18.16b, v16.16b, v0.16b
@ -79,16 +77,14 @@ static const unsigned int kSplice_dstover_lowp[] = {
0x6e670e87, // uqadd v7.8h, v20.8h, v7.8h
};
static const unsigned int kSplice_clamp_1_lowp[] = {
0x91000868, // add x8, x3, #0x2
0x4d40c510, // ld1r {v16.8h}, [x8]
0x4d40c470, // ld1r {v16.8h}, [x3]
0x6e706c00, // umin v0.8h, v0.8h, v16.8h
0x6e706c21, // umin v1.8h, v1.8h, v16.8h
0x6e706c42, // umin v2.8h, v2.8h, v16.8h
0x6e706c63, // umin v3.8h, v3.8h, v16.8h
};
static const unsigned int kSplice_clamp_a_lowp[] = {
0x91000868, // add x8, x3, #0x2
0x4d40c510, // ld1r {v16.8h}, [x8]
0x4d40c470, // ld1r {v16.8h}, [x3]
0x6e706c63, // umin v3.8h, v3.8h, v16.8h
0x6e636c00, // umin v0.8h, v0.8h, v3.8h
0x6e636c21, // umin v1.8h, v1.8h, v3.8h
@ -197,8 +193,7 @@ static const unsigned int kSplice_plus__lowp[] = {
0xf3133017, // vqadd.u16 d3, d3, d7
};
static const unsigned int kSplice_srcover_lowp[] = {
0xe283c002, // add ip, r3, #2
0xf4ec0c5f, // vld1.16 {d16[]}, [ip :16]
0xf4e30c5f, // vld1.16 {d16[]}, [r3 :16]
0xf3500293, // vqsub.u16 d16, d16, d3
0xf3541b20, // vqrdmulh.s16 d17, d4, d16
0xf3552b20, // vqrdmulh.s16 d18, d5, d16
@ -222,8 +217,7 @@ static const unsigned int kSplice_srcover_lowp[] = {
0xf3143093, // vqadd.u16 d3, d20, d3
};
static const unsigned int kSplice_dstover_lowp[] = {
0xe283c002, // add ip, r3, #2
0xf4ec0c5f, // vld1.16 {d16[]}, [ip :16]
0xf4e30c5f, // vld1.16 {d16[]}, [r3 :16]
0xf3500297, // vqsub.u16 d16, d16, d7
0xf3501b20, // vqrdmulh.s16 d17, d0, d16
0xf3512b20, // vqrdmulh.s16 d18, d1, d16
@ -247,16 +241,14 @@ static const unsigned int kSplice_dstover_lowp[] = {
0xf3147097, // vqadd.u16 d7, d20, d7
};
static const unsigned int kSplice_clamp_1_lowp[] = {
0xe283c002, // add ip, r3, #2
0xf4ec0c5f, // vld1.16 {d16[]}, [ip :16]
0xf4e30c5f, // vld1.16 {d16[]}, [r3 :16]
0xf3100630, // vmin.u16 d0, d0, d16
0xf3111630, // vmin.u16 d1, d1, d16
0xf3122630, // vmin.u16 d2, d2, d16
0xf3133630, // vmin.u16 d3, d3, d16
};
static const unsigned int kSplice_clamp_a_lowp[] = {
0xe283c002, // add ip, r3, #2
0xf4ec0c5f, // vld1.16 {d16[]}, [ip :16]
0xf4e30c5f, // vld1.16 {d16[]}, [r3 :16]
0xf3133630, // vmin.u16 d3, d3, d16
0xf3100613, // vmin.u16 d0, d0, d3
0xf3111613, // vmin.u16 d1, d1, d3
@ -376,7 +368,7 @@ static const unsigned char kSplice_plus__lowp[] = {
0xc5,0xe5,0xdd,0xdf, // vpaddusw %ymm7,%ymm3,%ymm3
};
static const unsigned char kSplice_srcover_lowp[] = {
0xc4,0x62,0x7d,0x79,0x41,0x02, // vpbroadcastw 0x2(%rcx),%ymm8
0xc4,0x62,0x7d,0x79,0x01, // vpbroadcastw (%rcx),%ymm8
0xc5,0x3d,0xd9,0xc3, // vpsubusw %ymm3,%ymm8,%ymm8
0xc4,0x42,0x5d,0x0b,0xc8, // vpmulhrsw %ymm8,%ymm4,%ymm9
0xc4,0x42,0x7d,0x1d,0xc9, // vpabsw %ymm9,%ymm9
@ -392,7 +384,7 @@ static const unsigned char kSplice_srcover_lowp[] = {
0xc5,0xbd,0xdd,0xdb, // vpaddusw %ymm3,%ymm8,%ymm3
};
static const unsigned char kSplice_dstover_lowp[] = {
0xc4,0x62,0x7d,0x79,0x41,0x02, // vpbroadcastw 0x2(%rcx),%ymm8
0xc4,0x62,0x7d,0x79,0x01, // vpbroadcastw (%rcx),%ymm8
0xc5,0x3d,0xd9,0xc7, // vpsubusw %ymm7,%ymm8,%ymm8
0xc4,0x42,0x7d,0x0b,0xc8, // vpmulhrsw %ymm8,%ymm0,%ymm9
0xc4,0x42,0x7d,0x1d,0xc9, // vpabsw %ymm9,%ymm9
@ -408,14 +400,14 @@ static const unsigned char kSplice_dstover_lowp[] = {
0xc5,0xbd,0xdd,0xff, // vpaddusw %ymm7,%ymm8,%ymm7
};
static const unsigned char kSplice_clamp_1_lowp[] = {
0xc4,0x62,0x7d,0x79,0x41,0x02, // vpbroadcastw 0x2(%rcx),%ymm8
0xc4,0x62,0x7d,0x79,0x01, // vpbroadcastw (%rcx),%ymm8
0xc4,0xc2,0x7d,0x3a,0xc0, // vpminuw %ymm8,%ymm0,%ymm0
0xc4,0xc2,0x75,0x3a,0xc8, // vpminuw %ymm8,%ymm1,%ymm1
0xc4,0xc2,0x6d,0x3a,0xd0, // vpminuw %ymm8,%ymm2,%ymm2
0xc4,0xc2,0x65,0x3a,0xd8, // vpminuw %ymm8,%ymm3,%ymm3
};
static const unsigned char kSplice_clamp_a_lowp[] = {
0xc4,0x62,0x7d,0x79,0x41,0x02, // vpbroadcastw 0x2(%rcx),%ymm8
0xc4,0x62,0x7d,0x79,0x01, // vpbroadcastw (%rcx),%ymm8
0xc4,0xc2,0x65,0x3a,0xd8, // vpminuw %ymm8,%ymm3,%ymm3
0xc4,0xe2,0x7d,0x3a,0xc3, // vpminuw %ymm3,%ymm0,%ymm0
0xc4,0xe2,0x75,0x3a,0xcb, // vpminuw %ymm3,%ymm1,%ymm1
@ -458,13 +450,9 @@ static const unsigned char kSplice_premul_lowp[] = {
static const unsigned char kSplice_scale_u8_lowp[] = {
0x48,0x8b,0x02, // mov (%rdx),%rax
0xc4,0x62,0x7d,0x30,0x04,0x38, // vpmovzxbw (%rax,%rdi,1),%ymm8
0xc4,0xc1,0x35,0x71,0xf0,0x07, // vpsllw $0x7,%ymm8,%ymm9
0xc4,0xc1,0x2d,0x71,0xd0,0x01, // vpsrlw $0x1,%ymm8,%ymm10
0xc4,0x41,0x35,0xdd,0xca, // vpaddusw %ymm10,%ymm9,%ymm9
0xc4,0x62,0x7d,0x79,0x11, // vpbroadcastw (%rcx),%ymm10
0xc4,0x41,0x3d,0xdd,0xc2, // vpaddusw %ymm10,%ymm8,%ymm8
0xc4,0xc1,0x3d,0x71,0xd0,0x08, // vpsrlw $0x8,%ymm8,%ymm8
0xc4,0x41,0x35,0xdd,0xc0, // vpaddusw %ymm8,%ymm9,%ymm8
0xc4,0xc1,0x3d,0x71,0xf0,0x08, // vpsllw $0x8,%ymm8,%ymm8
0xc4,0x62,0x7d,0x79,0x49,0x02, // vpbroadcastw 0x2(%rcx),%ymm9
0xc4,0x41,0x3d,0xe4,0xc1, // vpmulhuw %ymm9,%ymm8,%ymm8
0xc4,0xc2,0x7d,0x0b,0xc0, // vpmulhrsw %ymm8,%ymm0,%ymm0
0xc4,0xe2,0x7d,0x1d,0xc0, // vpabsw %ymm0,%ymm0
0xc4,0xc2,0x75,0x0b,0xc8, // vpmulhrsw %ymm8,%ymm1,%ymm1
@ -494,37 +482,21 @@ static const unsigned char kSplice_load_8888_lowp[] = {
0xc5,0x39,0x68,0xc1, // vpunpckhbw %xmm1,%xmm8,%xmm8
0xc5,0xe9,0x6c,0xc3, // vpunpcklqdq %xmm3,%xmm2,%xmm0
0xc4,0xe2,0x7d,0x30,0xc0, // vpmovzxbw %xmm0,%ymm0
0xc5,0xf5,0x71,0xf0,0x07, // vpsllw $0x7,%ymm0,%ymm1
0xc5,0xad,0x71,0xd0,0x01, // vpsrlw $0x1,%ymm0,%ymm10
0xc4,0xc1,0x75,0xdd,0xca, // vpaddusw %ymm10,%ymm1,%ymm1
0xc4,0x62,0x7d,0x79,0x11, // vpbroadcastw (%rcx),%ymm10
0xc4,0xc1,0x7d,0xdd,0xc2, // vpaddusw %ymm10,%ymm0,%ymm0
0xc5,0xfd,0x71,0xd0,0x08, // vpsrlw $0x8,%ymm0,%ymm0
0xc5,0xf5,0xdd,0xc0, // vpaddusw %ymm0,%ymm1,%ymm0
0xc5,0xfd,0x71,0xf0,0x08, // vpsllw $0x8,%ymm0,%ymm0
0xc4,0x62,0x7d,0x79,0x51,0x02, // vpbroadcastw 0x2(%rcx),%ymm10
0xc4,0xc1,0x7d,0xe4,0xc2, // vpmulhuw %ymm10,%ymm0,%ymm0
0xc5,0xe9,0x6d,0xcb, // vpunpckhqdq %xmm3,%xmm2,%xmm1
0xc4,0xe2,0x7d,0x30,0xc9, // vpmovzxbw %xmm1,%ymm1
0xc5,0xed,0x71,0xf1,0x07, // vpsllw $0x7,%ymm1,%ymm2
0xc5,0xe5,0x71,0xd1,0x01, // vpsrlw $0x1,%ymm1,%ymm3
0xc5,0xed,0xdd,0xd3, // vpaddusw %ymm3,%ymm2,%ymm2
0xc4,0xc1,0x75,0xdd,0xca, // vpaddusw %ymm10,%ymm1,%ymm1
0xc5,0xf5,0x71,0xd1,0x08, // vpsrlw $0x8,%ymm1,%ymm1
0xc5,0xed,0xdd,0xc9, // vpaddusw %ymm1,%ymm2,%ymm1
0xc5,0xf5,0x71,0xf1,0x08, // vpsllw $0x8,%ymm1,%ymm1
0xc4,0xc1,0x75,0xe4,0xca, // vpmulhuw %ymm10,%ymm1,%ymm1
0xc4,0xc1,0x31,0x6c,0xd0, // vpunpcklqdq %xmm8,%xmm9,%xmm2
0xc4,0xe2,0x7d,0x30,0xd2, // vpmovzxbw %xmm2,%ymm2
0xc5,0xe5,0x71,0xf2,0x07, // vpsllw $0x7,%ymm2,%ymm3
0xc5,0xa5,0x71,0xd2,0x01, // vpsrlw $0x1,%ymm2,%ymm11
0xc4,0xc1,0x65,0xdd,0xdb, // vpaddusw %ymm11,%ymm3,%ymm3
0xc4,0xc1,0x6d,0xdd,0xd2, // vpaddusw %ymm10,%ymm2,%ymm2
0xc5,0xed,0x71,0xd2,0x08, // vpsrlw $0x8,%ymm2,%ymm2
0xc5,0xe5,0xdd,0xd2, // vpaddusw %ymm2,%ymm3,%ymm2
0xc5,0xed,0x71,0xf2,0x08, // vpsllw $0x8,%ymm2,%ymm2
0xc4,0xc1,0x6d,0xe4,0xd2, // vpmulhuw %ymm10,%ymm2,%ymm2
0xc4,0xc1,0x31,0x6d,0xd8, // vpunpckhqdq %xmm8,%xmm9,%xmm3
0xc4,0xe2,0x7d,0x30,0xdb, // vpmovzxbw %xmm3,%ymm3
0xc5,0xbd,0x71,0xf3,0x07, // vpsllw $0x7,%ymm3,%ymm8
0xc5,0xb5,0x71,0xd3,0x01, // vpsrlw $0x1,%ymm3,%ymm9
0xc4,0x41,0x3d,0xdd,0xc1, // vpaddusw %ymm9,%ymm8,%ymm8
0xc4,0xc1,0x65,0xdd,0xda, // vpaddusw %ymm10,%ymm3,%ymm3
0xc5,0xe5,0x71,0xd3,0x08, // vpsrlw $0x8,%ymm3,%ymm3
0xc5,0xbd,0xdd,0xdb, // vpaddusw %ymm3,%ymm8,%ymm3
0xc5,0xe5,0x71,0xf3,0x08, // vpsllw $0x8,%ymm3,%ymm3
0xc4,0xc1,0x65,0xe4,0xda, // vpmulhuw %ymm10,%ymm3,%ymm3
};
static const unsigned char kSplice_store_8888_lowp[] = {
0x48,0x8b,0x02, // mov (%rdx),%rax

2
src/splicer/SkSplicer_shared.h
View File

@ -41,8 +41,8 @@ struct SkSplicer_constants {
};
struct SkSplicer_constants_lowp {
uint16_t _0x0001; // 0x0001 == 1 == epsilon
uint16_t _1; // 0x8000 == 32768 == 1.0
uint16_t _0x8081; // 0x8081 == 32897, closest value to 32768 * (256/255).
};
#endif//SkSplicer_shared_DEFINED

6
src/splicer/SkSplicer_stages_lowp.cpp
View File

@ -124,9 +124,11 @@ using K = const SkSplicer_constants_lowp;
static F max(F a, F b) { return _mm256_max_epu16(a,b); }
static F from_u8(U8 u8, K* k) {
// Nothing too interesting here. We follow the stock SkFixed15 formula.
// Ideally we'd multiply by 32768/255 = 128.50196...
// We can approximate that very cheaply as 256*32897/65536 = 128.50391...
// 0 and 255 map to 0 and 32768 correctly, and the max error is 1 (on about 1/4 of values).
F u16 = _mm256_cvtepu8_epi16(u8);
return (u16 << 7) + (u16 >> 1) + ((u16+k->_0x0001)>>8);
return _mm256_mulhi_epu16(u16 << 8, F(k->_0x8081));
}
#endif