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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkJumper.h"
#include "SkJumper_misc.h"
#include <immintrin.h>
#if !defined(__SSSE3__) || !defined(__clang__) || !defined(__x86_64__)
#error "We're starting with just SSSE3 x86-64 for now, and will always require Clang."
#endif
#define WRAP(name) sk_##name##_ssse3_lowp
using K = const SkJumper_constants;
static const size_t kStride = 8;
template <typename T> using V = T __attribute__((ext_vector_type(8)));
using U8 = V<uint8_t>;
using U16 = V<uint16_t>;
using U32 = V<uint32_t>;
// See SkFixed15.h for details on this format and its operations.
struct F {
U16 vec;
F() = default;
F(uint16_t bits) : vec(bits) {}
F(U16 v) : vec(v) {}
operator U16() const { return vec; }
};
SI F operator+(F x, F y) { return x.vec + y.vec; }
SI F operator-(F x, F y) { return x.vec - y.vec; }
SI F operator*(F x, F y) { return _mm_abs_epi16(_mm_mulhrs_epi16(x.vec, y.vec)); }
SI F mad(F f, F m, F a) { return f*m+a; }
SI F operator<<(F x, int bits) { return x.vec << bits; }
SI F operator>>(F x, int bits) { return x.vec >> bits; }
using Stage = void(K* k, void** program, size_t x, size_t y, size_t tail, F,F,F,F, F,F,F,F);
MAYBE_MSABI
extern "C" size_t WRAP(start_pipeline)(size_t x, size_t y, size_t limit, void** program, K* k) {
F v{};
auto start = (Stage*)load_and_inc(program);
while (x + kStride <= limit) {
start(k,program,x,y,0, v,v,v,v, v,v,v,v);
x += kStride;
}
if (size_t tail = limit - x) {
start(k,program,x,y,tail, v,v,v,v, v,v,v,v);
}
return limit;
}
extern "C" void WRAP(just_return)(K*, void**, size_t,size_t,size_t, F,F,F,F, F,F,F,F) {}
#define STAGE(name) \
SI void name##_k(K* k, LazyCtx ctx, size_t x, size_t y, size_t tail, \
F& r, F& g, F& b, F& a, F& dr, F& dg, F& db, F& da); \
extern "C" void WRAP(name)(K* k, void** program, size_t x, size_t y, size_t tail, \
F r, F g, F b, F a, F dr, F dg, F db, F da) { \
LazyCtx ctx(program); \
name##_k(k,ctx,x,y,tail, r,g,b,a, dr,dg,db,da); \
auto next = (Stage*)load_and_inc(program); \
next(k,program,x,y,tail, r,g,b,a, dr,dg,db,da); \
} \
SI void name##_k(K* k, LazyCtx ctx, size_t x, size_t y, size_t tail, \
F& r, F& g, F& b, F& a, F& dr, F& dg, F& db, F& da)
// Helper functions used by multiple stages.
template <typename V, typename T>
SI V load(const T* src, size_t tail) {
#if defined(JUMPER)
__builtin_assume(tail < kStride);
if (__builtin_expect(tail, 0)) {
V v{}; // Any inactive lanes are zeroed.
switch (tail-1) {
case 6: v[6] = src[6];
case 5: v[5] = src[5];
case 4: v[4] = src[4];
case 3: v[3] = src[3];
case 2: v[2] = src[2];
case 1: v[1] = src[1];
case 0: v[0] = src[0];
}
return v;
}
#endif
return unaligned_load<V>(src);
}
template <typename V, typename T>
SI void store(T* dst, V v, size_t tail) {
#if defined(JUMPER)
__builtin_assume(tail < kStride);
if (__builtin_expect(tail, 0)) {
switch (tail-1) {
case 6: dst[6] = v[6];
case 5: dst[5] = v[5];
case 4: dst[4] = v[4];
case 3: dst[3] = v[3];
case 2: dst[2] = v[2];
case 1: dst[1] = v[1];
case 0: dst[0] = v[0];
}
return;
}
#endif
unaligned_store(dst, v);
}
SI void from_8888(U32 rgba, F* r, F* g, F* b, F* a) {
// Split the 8 pixels into low and high halves, and reinterpret as vectors of 16-bit values.
U16 lo = unaligned_load<U16>((const uint32_t*)&rgba + 0),
hi = unaligned_load<U16>((const uint32_t*)&rgba + 4);
U16 _0415 = _mm_unpacklo_epi8(lo, hi), // r0 r4 g0 g4 b0 b4 a0 a4 r1 r5 g1 g5 b1 b5 a1 a5
_2637 = _mm_unpackhi_epi8(lo, hi);
U16 even = _mm_unpacklo_epi8(_0415, _2637), // r0 r2 r4 r6 g0 g2 g4 g6 b0 b2 b4 b6 a0 a2 a4 a6
odd = _mm_unpackhi_epi8(_0415, _2637);
U16 rg = _mm_unpacklo_epi8(even, odd), // r0 r1 r2 r3 r4 r5 r6 r7 g0 g1 g2 g3 g4 g5 g6 g7
ba = _mm_unpackhi_epi8(even, odd);
// Unpack as 16-bit values into the high half of each 16-bit lane, to get a free *256.
U16 R = _mm_unpacklo_epi8(U16(0), rg),
G = _mm_unpackhi_epi8(U16(0), rg),
B = _mm_unpacklo_epi8(U16(0), ba),
A = _mm_unpackhi_epi8(U16(0), ba);
// Now we scale from [0,255] to [0,32768]. Ideally that's 32768/255 = 128.50196,
// but we can approximate that very cheaply as 256*32897/65536 = 128.50391.
// 0 and 255 map to 0 and 32768 correctly, and nothing else is off by more than 1.
*r = _mm_mulhi_epu16(R, U16(32897));
*g = _mm_mulhi_epu16(G, U16(32897));
*b = _mm_mulhi_epu16(B, U16(32897));
*a = _mm_mulhi_epu16(A, U16(32897));
}
SI U32 to_8888(F r, F g, F b, F a) {
// We want to interlace and pack these values from [0,32768] to [0,255].
// Luckily the simplest possible thing works great: >>7, then saturate.
// The 'u' in packus handles the saturation to [0,255] we need.
U16 rb = _mm_packus_epi16(r>>7,b>>7), // r0 r1 r2 r3 r4 r5 r6 r7 b0 b1 b2 b3 b4 b5 b6 b7
ga = _mm_packus_epi16(g>>7,a>>7);
U16 rg = _mm_unpacklo_epi8(rb, ga), // r0 g0 r1 g1 ... r7 g7
ba = _mm_unpackhi_epi8(rb, ga); // b0 a0 ... b7 a7
U16 lo = _mm_unpacklo_epi16(rg, ba), // r0 g0 b0 a0 ... r3 g3 b3 a3
hi = _mm_unpackhi_epi16(rg, ba); // r4 g4 b4 a4 ... r7 g7 b7 a7
U32 px;
memcpy((uint32_t*)&px + 0, &lo, sizeof(lo));
memcpy((uint32_t*)&px + 4, &hi, sizeof(hi));
return px;
}
// Stages!
STAGE(load_8888) {
auto ptr = *(const uint32_t**)ctx + x;
from_8888(load<U32>(ptr, tail), &r,&g,&b,&a);
}
STAGE(store_8888) {
auto ptr = *(uint32_t**)ctx + x;
store(ptr, to_8888(r,g,b,a), tail);
}
STAGE(swap_rb) {
auto tmp = r;
r = b;
b = tmp;
}
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