skia2/include/private/SkVx.h
Mike Klein f4438d56e9 skvx: allow more implicit conversions
Guarding the implict constructors and scalar/vector
operations with std::is_convertible ought to make SkVx
types feel more like normal C types, allowing implicit
conversions exactly when the scalar equivalents would.

This shouldn't change the behavior of any code, or make
anything new possible... just nicer to read and write.

Change-Id: Iff4b89012c5b8c7f7933e6841c925b81186bc614
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201402
Commit-Queue: Mike Klein <mtklein@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
2019-03-14 19:11:21 +00:00

452 lines
21 KiB
C++

/*
* Copyright 2019 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SKVX_DEFINED
#define SKVX_DEFINED
// skvx::Vec<N,T> are SIMD vectors of N T's, a v1.5 successor to SkNx<N,T>.
//
// This time we're leaning a bit less on platform-specific intrinsics and a bit
// more on Clang/GCC vector extensions, but still keeping the option open to
// drop in platform-specific intrinsics, actually more easily than before.
//
// We've also fixed a few of the caveats that used to make SkNx awkward to work
// with across translation units. skvx::Vec<N,T> always has N*sizeof(T) size
// and alignof(T) alignment and is safe to use across translation units freely.
#include "SkTypes.h" // SK_CPU_SSE_LEVEL*, etc.
#include <algorithm> // std::min, std::max
#include <cmath> // std::ceil, std::floor, std::trunc, std::round, std::sqrt, etc.
#include <cstdint> // intXX_t
#include <cstring> // memcpy()
#include <initializer_list> // std::initializer_list
#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE1
#include <immintrin.h>
#elif defined(SK_ARM_HAS_NEON)
#include <arm_neon.h>
#endif
namespace skvx {
// All Vec have the same simple memory layout, the same as `T vec[N]`.
// This gives Vec a consistent ABI, letting them pass between files compiled with
// different instruction sets (e.g. SSE2 and AVX2) without fear of ODR violation.
template <int N, typename T>
struct Vec {
static_assert((N & (N-1)) == 0, "N must be a power of 2.");
Vec<N/2,T> lo, hi;
// Methods belong here in the class declaration of Vec only if:
// - they must be here, like constructors or operator[];
// - they'll definitely never want a specialized implementation.
// Other operations on Vec should be defined outside the type.
Vec() = default;
template <typename U,
typename=typename std::enable_if<std::is_convertible<U,T>::value>::type>
Vec(U x) : lo(x), hi(x) {}
Vec(std::initializer_list<T> xs) {
T vals[N] = {0};
memcpy(vals, xs.begin(), std::min(xs.size(), (size_t)N)*sizeof(T));
lo = Vec<N/2,T>::Load(vals + 0);
hi = Vec<N/2,T>::Load(vals + N/2);
}
T operator[](int i) const { return i < N/2 ? lo[i] : hi[i-N/2]; }
T& operator[](int i) { return i < N/2 ? lo[i] : hi[i-N/2]; }
static Vec Load(const void* ptr) {
Vec v;
memcpy(&v, ptr, sizeof(Vec));
return v;
}
void store(void* ptr) const {
memcpy(ptr, this, sizeof(Vec));
}
};
template <typename T>
struct Vec<1,T> {
T val;
Vec() = default;
template <typename U,
typename=typename std::enable_if<std::is_convertible<U,T>::value>::type>
Vec(U x) : val(x) {}
Vec(std::initializer_list<T> xs) : val(xs.size() ? *xs.begin() : 0) {}
T operator[](int) const { return val; }
T& operator[](int) { return val; }
static Vec Load(const void* ptr) {
Vec v;
memcpy(&v, ptr, sizeof(Vec));
return v;
}
void store(void* ptr) const {
memcpy(ptr, this, sizeof(Vec));
}
};
#if defined(__GNUC__) && !defined(__clang__) && SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE1
// GCC warns about ABI changes when returning >= 32 byte vectors when -mavx is not enabled.
// This only happens for types like VExt whose ABI we don't care about, not for Vec itself.
#pragma GCC diagnostic ignored "-Wpsabi"
#endif
// Helps tamp down on the repetitive boilerplate.
#define SI static inline
#define SIT template < typename T> static inline
#define SINT template <int N, typename T> static inline
#define SINTU template <int N, typename T, typename U, \
typename=typename std::enable_if<std::is_convertible<U,T>::value>::type> \
static inline
template <typename D, typename S>
SI D bit_pun(S s) {
static_assert(sizeof(D) == sizeof(S), "");
D d;
memcpy(&d, &s, sizeof(D));
return d;
}
// Translate from a value type T to its corresponding Mask, the result of a comparison.
template <typename T> struct Mask { using type = T; };
template <> struct Mask<float > { using type = int32_t; };
template <> struct Mask<double> { using type = int64_t; };
template <typename T> using M = typename Mask<T>::type;
// Join two Vec<N,T> into one Vec<2N,T>.
SINT Vec<2*N,T> join(Vec<N,T> lo, Vec<N,T> hi) {
Vec<2*N,T> v;
v.lo = lo;
v.hi = hi;
return v;
}
// We have two default strategies for implementing most operations:
// 1) lean on Clang/GCC vector extensions when available;
// 2) recurse to scalar portable implementations when not.
// At the end we can drop in platform-specific implementations that override either default.
#if !defined(SKNX_NO_SIMD) && (defined(__clang__) || defined(__GNUC__))
// VExt<N,T> types have the same size as Vec<N,T> and support most operations directly.
// N.B. VExt<N,T> alignment is N*alignof(T), stricter than Vec<N,T>'s alignof(T).
#if defined(__clang__)
template <int N, typename T>
using VExt = T __attribute__((ext_vector_type(N)));
#elif defined(__GNUC__)
template <int N, typename T>
struct VExtHelper {
typedef T __attribute__((vector_size(N*sizeof(T)))) type;
};
template <int N, typename T>
using VExt = typename VExtHelper<N,T>::type;
// For some reason some (new!) versions of GCC cannot seem to deduce N in the generic
// to_vec<N,T>() below for N=4 and T=float. This workaround seems to help...
SI Vec<4,float> to_vec(VExt<4,float> v) { return bit_pun<Vec<4,float>>(v); }
#endif
SINT VExt<N,T> to_vext(Vec<N,T> v) { return bit_pun<VExt<N,T>>(v); }
SINT Vec <N,T> to_vec(VExt<N,T> v) { return bit_pun<Vec <N,T>>(v); }
SINT Vec<N,T> operator+(Vec<N,T> x, Vec<N,T> y) { return to_vec(to_vext(x) + to_vext(y)); }
SINT Vec<N,T> operator-(Vec<N,T> x, Vec<N,T> y) { return to_vec(to_vext(x) - to_vext(y)); }
SINT Vec<N,T> operator*(Vec<N,T> x, Vec<N,T> y) { return to_vec(to_vext(x) * to_vext(y)); }
SINT Vec<N,T> operator/(Vec<N,T> x, Vec<N,T> y) { return to_vec(to_vext(x) / to_vext(y)); }
SINT Vec<N,T> operator^(Vec<N,T> x, Vec<N,T> y) { return to_vec(to_vext(x) ^ to_vext(y)); }
SINT Vec<N,T> operator&(Vec<N,T> x, Vec<N,T> y) { return to_vec(to_vext(x) & to_vext(y)); }
SINT Vec<N,T> operator|(Vec<N,T> x, Vec<N,T> y) { return to_vec(to_vext(x) | to_vext(y)); }
SINT Vec<N,T> operator!(Vec<N,T> x) { return to_vec(!to_vext(x)); }
SINT Vec<N,T> operator-(Vec<N,T> x) { return to_vec(-to_vext(x)); }
SINT Vec<N,T> operator~(Vec<N,T> x) { return to_vec(~to_vext(x)); }
SINT Vec<N,T> operator<<(Vec<N,T> x, int bits) { return to_vec(to_vext(x) << bits); }
SINT Vec<N,T> operator>>(Vec<N,T> x, int bits) { return to_vec(to_vext(x) >> bits); }
SINT Vec<N,M<T>> operator==(Vec<N,T> x, Vec<N,T> y) { return bit_pun<Vec<N,M<T>>>(to_vext(x) == to_vext(y)); }
SINT Vec<N,M<T>> operator!=(Vec<N,T> x, Vec<N,T> y) { return bit_pun<Vec<N,M<T>>>(to_vext(x) != to_vext(y)); }
SINT Vec<N,M<T>> operator<=(Vec<N,T> x, Vec<N,T> y) { return bit_pun<Vec<N,M<T>>>(to_vext(x) <= to_vext(y)); }
SINT Vec<N,M<T>> operator>=(Vec<N,T> x, Vec<N,T> y) { return bit_pun<Vec<N,M<T>>>(to_vext(x) >= to_vext(y)); }
SINT Vec<N,M<T>> operator< (Vec<N,T> x, Vec<N,T> y) { return bit_pun<Vec<N,M<T>>>(to_vext(x) < to_vext(y)); }
SINT Vec<N,M<T>> operator> (Vec<N,T> x, Vec<N,T> y) { return bit_pun<Vec<N,M<T>>>(to_vext(x) > to_vext(y)); }
#else
// Either SKNX_NO_SIMD is defined, or Clang/GCC vector extensions are not available.
// We'll implement things portably, in a way that should be easily autovectorizable.
// N == 1 scalar implementations.
SIT Vec<1,T> operator+(Vec<1,T> x, Vec<1,T> y) { return x.val + y.val; }
SIT Vec<1,T> operator-(Vec<1,T> x, Vec<1,T> y) { return x.val - y.val; }
SIT Vec<1,T> operator*(Vec<1,T> x, Vec<1,T> y) { return x.val * y.val; }
SIT Vec<1,T> operator/(Vec<1,T> x, Vec<1,T> y) { return x.val / y.val; }
SIT Vec<1,T> operator^(Vec<1,T> x, Vec<1,T> y) { return x.val ^ y.val; }
SIT Vec<1,T> operator&(Vec<1,T> x, Vec<1,T> y) { return x.val & y.val; }
SIT Vec<1,T> operator|(Vec<1,T> x, Vec<1,T> y) { return x.val | y.val; }
SIT Vec<1,T> operator!(Vec<1,T> x) { return !x.val; }
SIT Vec<1,T> operator-(Vec<1,T> x) { return -x.val; }
SIT Vec<1,T> operator~(Vec<1,T> x) { return ~x.val; }
SIT Vec<1,T> operator<<(Vec<1,T> x, int bits) { return x.val << bits; }
SIT Vec<1,T> operator>>(Vec<1,T> x, int bits) { return x.val >> bits; }
SIT Vec<1,M<T>> operator==(Vec<1,T> x, Vec<1,T> y) { return x.val == y.val ? ~0 : 0; }
SIT Vec<1,M<T>> operator!=(Vec<1,T> x, Vec<1,T> y) { return x.val != y.val ? ~0 : 0; }
SIT Vec<1,M<T>> operator<=(Vec<1,T> x, Vec<1,T> y) { return x.val <= y.val ? ~0 : 0; }
SIT Vec<1,M<T>> operator>=(Vec<1,T> x, Vec<1,T> y) { return x.val >= y.val ? ~0 : 0; }
SIT Vec<1,M<T>> operator< (Vec<1,T> x, Vec<1,T> y) { return x.val < y.val ? ~0 : 0; }
SIT Vec<1,M<T>> operator> (Vec<1,T> x, Vec<1,T> y) { return x.val > y.val ? ~0 : 0; }
// All default N != 1 implementations just recurse on lo and hi halves.
SINT Vec<N,T> operator+(Vec<N,T> x, Vec<N,T> y) { return join(x.lo + y.lo, x.hi + y.hi); }
SINT Vec<N,T> operator-(Vec<N,T> x, Vec<N,T> y) { return join(x.lo - y.lo, x.hi - y.hi); }
SINT Vec<N,T> operator*(Vec<N,T> x, Vec<N,T> y) { return join(x.lo * y.lo, x.hi * y.hi); }
SINT Vec<N,T> operator/(Vec<N,T> x, Vec<N,T> y) { return join(x.lo / y.lo, x.hi / y.hi); }
SINT Vec<N,T> operator^(Vec<N,T> x, Vec<N,T> y) { return join(x.lo ^ y.lo, x.hi ^ y.hi); }
SINT Vec<N,T> operator&(Vec<N,T> x, Vec<N,T> y) { return join(x.lo & y.lo, x.hi & y.hi); }
SINT Vec<N,T> operator|(Vec<N,T> x, Vec<N,T> y) { return join(x.lo | y.lo, x.hi | y.hi); }
SINT Vec<N,T> operator!(Vec<N,T> x) { return join(!x.lo, !x.hi); }
SINT Vec<N,T> operator-(Vec<N,T> x) { return join(-x.lo, -x.hi); }
SINT Vec<N,T> operator~(Vec<N,T> x) { return join(~x.lo, ~x.hi); }
SINT Vec<N,T> operator<<(Vec<N,T> x, int bits) { return join(x.lo << bits, x.hi << bits); }
SINT Vec<N,T> operator>>(Vec<N,T> x, int bits) { return join(x.lo >> bits, x.hi >> bits); }
SINT Vec<N,M<T>> operator==(Vec<N,T> x, Vec<N,T> y) { return join(x.lo == y.lo, x.hi == y.hi); }
SINT Vec<N,M<T>> operator!=(Vec<N,T> x, Vec<N,T> y) { return join(x.lo != y.lo, x.hi != y.hi); }
SINT Vec<N,M<T>> operator<=(Vec<N,T> x, Vec<N,T> y) { return join(x.lo <= y.lo, x.hi <= y.hi); }
SINT Vec<N,M<T>> operator>=(Vec<N,T> x, Vec<N,T> y) { return join(x.lo >= y.lo, x.hi >= y.hi); }
SINT Vec<N,M<T>> operator< (Vec<N,T> x, Vec<N,T> y) { return join(x.lo < y.lo, x.hi < y.hi); }
SINT Vec<N,M<T>> operator> (Vec<N,T> x, Vec<N,T> y) { return join(x.lo > y.lo, x.hi > y.hi); }
#endif
// Some operations we want are not expressible with Clang/GCC vector
// extensions, so we implement them using the recursive approach.
// N == 1 scalar implementations.
SIT Vec<1,T> if_then_else(Vec<1,M<T>> cond, Vec<1,T> t, Vec<1,T> e) {
auto t_bits = bit_pun<M<T>>(t),
e_bits = bit_pun<M<T>>(e);
return bit_pun<T>( (cond.val & t_bits) | (~cond.val & e_bits) );
}
SIT bool any(Vec<1,T> x) { return x.val != 0; }
SIT bool all(Vec<1,T> x) { return x.val != 0; }
SIT T min(Vec<1,T> x) { return x.val; }
SIT T max(Vec<1,T> x) { return x.val; }
SIT Vec<1,T> min(Vec<1,T> x, Vec<1,T> y) { return std::min(x.val, y.val); }
SIT Vec<1,T> max(Vec<1,T> x, Vec<1,T> y) { return std::max(x.val, y.val); }
SIT Vec<1,T> ceil(Vec<1,T> x) { return std:: ceil(x.val); }
SIT Vec<1,T> floor(Vec<1,T> x) { return std::floor(x.val); }
SIT Vec<1,T> trunc(Vec<1,T> x) { return std::trunc(x.val); }
SIT Vec<1,T> round(Vec<1,T> x) { return std::round(x.val); }
SIT Vec<1,T> sqrt(Vec<1,T> x) { return std:: sqrt(x.val); }
SIT Vec<1,T> abs(Vec<1,T> x) { return std:: abs(x.val); }
SIT Vec<1,T> rcp(Vec<1,T> x) { return 1 / x.val; }
SIT Vec<1,T> rsqrt(Vec<1,T> x) { return rcp(sqrt(x)); }
SIT Vec<1,T> mad(Vec<1,T> f,
Vec<1,T> m,
Vec<1,T> a) { return f*m+a; }
// All default N != 1 implementations just recurse on lo and hi halves.
SINT Vec<N,T> if_then_else(Vec<N,M<T>> cond, Vec<N,T> t, Vec<N,T> e) {
return join(if_then_else(cond.lo, t.lo, e.lo),
if_then_else(cond.hi, t.hi, e.hi));
}
SINT bool any(Vec<N,T> x) { return any(x.lo) || any(x.hi); }
SINT bool all(Vec<N,T> x) { return all(x.lo) && all(x.hi); }
SINT T min(Vec<N,T> x) { return std::min(min(x.lo), min(x.hi)); }
SINT T max(Vec<N,T> x) { return std::max(max(x.lo), max(x.hi)); }
SINT Vec<N,T> min(Vec<N,T> x, Vec<N,T> y) { return join(min(x.lo, y.lo), min(x.hi, y.hi)); }
SINT Vec<N,T> max(Vec<N,T> x, Vec<N,T> y) { return join(max(x.lo, y.lo), max(x.hi, y.hi)); }
SINT Vec<N,T> ceil(Vec<N,T> x) { return join( ceil(x.lo), ceil(x.hi)); }
SINT Vec<N,T> floor(Vec<N,T> x) { return join(floor(x.lo), floor(x.hi)); }
SINT Vec<N,T> trunc(Vec<N,T> x) { return join(trunc(x.lo), trunc(x.hi)); }
SINT Vec<N,T> round(Vec<N,T> x) { return join(round(x.lo), round(x.hi)); }
SINT Vec<N,T> sqrt(Vec<N,T> x) { return join( sqrt(x.lo), sqrt(x.hi)); }
SINT Vec<N,T> abs(Vec<N,T> x) { return join( abs(x.lo), abs(x.hi)); }
SINT Vec<N,T> rcp(Vec<N,T> x) { return join( rcp(x.lo), rcp(x.hi)); }
SINT Vec<N,T> rsqrt(Vec<N,T> x) { return join(rsqrt(x.lo), rsqrt(x.hi)); }
SINT Vec<N,T> mad(Vec<N,T> f,
Vec<N,T> m,
Vec<N,T> a) { return join(mad(f.lo, m.lo, a.lo), mad(f.hi, m.hi, a.hi)); }
// Scalar/vector operations just splat the scalar to a vector...
SINTU Vec<N,T> operator+ (U x, Vec<N,T> y) { return Vec<N,T>(x) + y; }
SINTU Vec<N,T> operator- (U x, Vec<N,T> y) { return Vec<N,T>(x) - y; }
SINTU Vec<N,T> operator* (U x, Vec<N,T> y) { return Vec<N,T>(x) * y; }
SINTU Vec<N,T> operator/ (U x, Vec<N,T> y) { return Vec<N,T>(x) / y; }
SINTU Vec<N,T> operator^ (U x, Vec<N,T> y) { return Vec<N,T>(x) ^ y; }
SINTU Vec<N,T> operator& (U x, Vec<N,T> y) { return Vec<N,T>(x) & y; }
SINTU Vec<N,T> operator| (U x, Vec<N,T> y) { return Vec<N,T>(x) | y; }
SINTU Vec<N,M<T>> operator==(U x, Vec<N,T> y) { return Vec<N,T>(x) == y; }
SINTU Vec<N,M<T>> operator!=(U x, Vec<N,T> y) { return Vec<N,T>(x) != y; }
SINTU Vec<N,M<T>> operator<=(U x, Vec<N,T> y) { return Vec<N,T>(x) <= y; }
SINTU Vec<N,M<T>> operator>=(U x, Vec<N,T> y) { return Vec<N,T>(x) >= y; }
SINTU Vec<N,M<T>> operator< (U x, Vec<N,T> y) { return Vec<N,T>(x) < y; }
SINTU Vec<N,M<T>> operator> (U x, Vec<N,T> y) { return Vec<N,T>(x) > y; }
SINTU Vec<N,T> min(U x, Vec<N,T> y) { return min(Vec<N,T>(x), y); }
SINTU Vec<N,T> max(U x, Vec<N,T> y) { return max(Vec<N,T>(x), y); }
// ... and same deal for vector/scalar operations.
SINTU Vec<N,T> operator+ (Vec<N,T> x, U y) { return x + Vec<N,T>(y); }
SINTU Vec<N,T> operator- (Vec<N,T> x, U y) { return x - Vec<N,T>(y); }
SINTU Vec<N,T> operator* (Vec<N,T> x, U y) { return x * Vec<N,T>(y); }
SINTU Vec<N,T> operator/ (Vec<N,T> x, U y) { return x / Vec<N,T>(y); }
SINTU Vec<N,T> operator^ (Vec<N,T> x, U y) { return x ^ Vec<N,T>(y); }
SINTU Vec<N,T> operator& (Vec<N,T> x, U y) { return x & Vec<N,T>(y); }
SINTU Vec<N,T> operator| (Vec<N,T> x, U y) { return x | Vec<N,T>(y); }
SINTU Vec<N,M<T>> operator==(Vec<N,T> x, U y) { return x == Vec<N,T>(y); }
SINTU Vec<N,M<T>> operator!=(Vec<N,T> x, U y) { return x != Vec<N,T>(y); }
SINTU Vec<N,M<T>> operator<=(Vec<N,T> x, U y) { return x <= Vec<N,T>(y); }
SINTU Vec<N,M<T>> operator>=(Vec<N,T> x, U y) { return x >= Vec<N,T>(y); }
SINTU Vec<N,M<T>> operator< (Vec<N,T> x, U y) { return x < Vec<N,T>(y); }
SINTU Vec<N,M<T>> operator> (Vec<N,T> x, U y) { return x > Vec<N,T>(y); }
SINTU Vec<N,T> min(Vec<N,T> x, U y) { return min(x, Vec<N,T>(y)); }
SINTU Vec<N,T> max(Vec<N,T> x, U y) { return max(x, Vec<N,T>(y)); }
// All vector/scalar combinations for mad() with at least one vector.
SINTU Vec<N,T> mad(U f, Vec<N,T> m, Vec<N,T> a) { return Vec<N,T>(f)*m + a; }
SINTU Vec<N,T> mad(Vec<N,T> f, U m, Vec<N,T> a) { return f*Vec<N,T>(m) + a; }
SINTU Vec<N,T> mad(Vec<N,T> f, Vec<N,T> m, U a) { return f*m + Vec<N,T>(a); }
SINTU Vec<N,T> mad(Vec<N,T> f, U m, U a) { return f*Vec<N,T>(m) + Vec<N,T>(a); }
SINTU Vec<N,T> mad(U f, Vec<N,T> m, U a) { return Vec<N,T>(f)*m + Vec<N,T>(a); }
SINTU Vec<N,T> mad(U f, U m, Vec<N,T> a) { return Vec<N,T>(f)*Vec<N,T>(m) + a; }
// The various op= operators, for vectors...
SINT Vec<N,T>& operator+=(Vec<N,T>& x, Vec<N,T> y) { return (x = x + y); }
SINT Vec<N,T>& operator-=(Vec<N,T>& x, Vec<N,T> y) { return (x = x - y); }
SINT Vec<N,T>& operator*=(Vec<N,T>& x, Vec<N,T> y) { return (x = x * y); }
SINT Vec<N,T>& operator/=(Vec<N,T>& x, Vec<N,T> y) { return (x = x / y); }
SINT Vec<N,T>& operator^=(Vec<N,T>& x, Vec<N,T> y) { return (x = x ^ y); }
SINT Vec<N,T>& operator&=(Vec<N,T>& x, Vec<N,T> y) { return (x = x & y); }
SINT Vec<N,T>& operator|=(Vec<N,T>& x, Vec<N,T> y) { return (x = x | y); }
// ... for scalars...
SINTU Vec<N,T>& operator+=(Vec<N,T>& x, U y) { return (x = x + Vec<N,T>(y)); }
SINTU Vec<N,T>& operator-=(Vec<N,T>& x, U y) { return (x = x - Vec<N,T>(y)); }
SINTU Vec<N,T>& operator*=(Vec<N,T>& x, U y) { return (x = x * Vec<N,T>(y)); }
SINTU Vec<N,T>& operator/=(Vec<N,T>& x, U y) { return (x = x / Vec<N,T>(y)); }
SINTU Vec<N,T>& operator^=(Vec<N,T>& x, U y) { return (x = x ^ Vec<N,T>(y)); }
SINTU Vec<N,T>& operator&=(Vec<N,T>& x, U y) { return (x = x & Vec<N,T>(y)); }
SINTU Vec<N,T>& operator|=(Vec<N,T>& x, U y) { return (x = x | Vec<N,T>(y)); }
// ... and for shifts.
SINT Vec<N,T>& operator<<=(Vec<N,T>& x, int bits) { return (x = x << bits); }
SINT Vec<N,T>& operator>>=(Vec<N,T>& x, int bits) { return (x = x >> bits); }
} // namespace skvx
// These next few routines take extra template arguments that prevent
// argument-dependent lookup. They must live outside the skvx namespace,
// but since they operate only on skvx::Vec, that shouldn't be a big deal.
// cast() Vec<N,S> to Vec<N,D>, as if applying a C-cast to each lane.
template <typename D, typename S>
SI skvx::Vec<1,D> cast(skvx::Vec<1,S> src) { return (D)src.val; }
template <typename D, int N, typename S>
SI skvx::Vec<N,D> cast(skvx::Vec<N,S> src) {
#if !defined(SKNX_NO_SIMD) && defined(__clang__)
return skvx::to_vec(__builtin_convertvector(skvx::to_vext(src), skvx::VExt<N,D>));
#else
return join(cast<D>(src.lo), cast<D>(src.hi));
#endif
}
// Shuffle values from a vector pretty arbitrarily:
// skvx::Vec<4,float> rgba = {R,G,B,A};
// shuffle<2,1,0,3> (rgba) ~> {B,G,R,A}
// shuffle<2,1> (rgba) ~> {B,G}
// shuffle<2,1,2,1,2,1,2,1>(rgba) ~> {B,G,B,G,B,G,B,G}
// shuffle<3,3,3,3> (rgba) ~> {A,A,A,A}
// The only real restriction is that the output also be a legal N=power-of-two sknx::Vec.
template <int... Ix, int N, typename T>
SI skvx::Vec<sizeof...(Ix),T> shuffle(skvx::Vec<N,T> x) {
return { x[Ix]... };
}
#if !defined(SKNX_NO_SIMD)
namespace skvx {
// Platform-specific specializations and overloads can now drop in here.
#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE1
SI Vec<4,float> sqrt(Vec<4,float> x) {
return bit_pun<Vec<4,float>>(_mm_sqrt_ps(bit_pun<__m128>(x)));
}
SI Vec<4,float> rsqrt(Vec<4,float> x) {
return bit_pun<Vec<4,float>>(_mm_rsqrt_ps(bit_pun<__m128>(x)));
}
SI Vec<4,float> rcp(Vec<4,float> x) {
return bit_pun<Vec<4,float>>(_mm_rcp_ps(bit_pun<__m128>(x)));
}
SI Vec<2,float> sqrt(Vec<2,float> x) { return shuffle<0,1>( sqrt(shuffle<0,1,0,1>(x))); }
SI Vec<2,float> rsqrt(Vec<2,float> x) { return shuffle<0,1>(rsqrt(shuffle<0,1,0,1>(x))); }
SI Vec<2,float> rcp(Vec<2,float> x) { return shuffle<0,1>( rcp(shuffle<0,1,0,1>(x))); }
#endif
#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE41
SI Vec<4,float> if_then_else(Vec<4,int> c, Vec<4,float> t, Vec<4,float> e) {
return bit_pun<Vec<4,float>>(_mm_blendv_ps(bit_pun<__m128>(e),
bit_pun<__m128>(t),
bit_pun<__m128>(c)));
}
#elif SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE1
SI Vec<4,float> if_then_else(Vec<4,int> c, Vec<4,float> t, Vec<4,float> e) {
return bit_pun<Vec<4,float>>(_mm_or_ps(_mm_and_ps (bit_pun<__m128>(c),
bit_pun<__m128>(t)),
_mm_andnot_ps(bit_pun<__m128>(c),
bit_pun<__m128>(e))));
}
#elif defined(SK_ARM_HAS_NEON)
SI Vec<4,float> if_then_else(Vec<4,int> c, Vec<4,float> t, Vec<4,float> e) {
return bit_pun<Vec<4,float>>(vbslq_f32(bit_pun<uint32x4_t> (c),
bit_pun<float32x4_t>(t),
bit_pun<float32x4_t>(e)));
}
#endif
} // namespace skvx
#endif // !defined(SKNX_NO_SIMD)
#undef SINTU
#undef SINT
#undef SIT
#undef SI
#endif//SKVX_DEFINED