| /* |
| * Copyright 2017 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkJumper_misc_DEFINED |
| #define SkJumper_misc_DEFINED |
| |
| #include "SkJumper.h" // for memcpy() |
| |
| // Miscellany used by SkJumper_stages.cpp and SkJumper_vectors.h. |
| |
| // Every function in this file should be marked static and inline using SI. |
| #if defined(JUMPER) |
| #define SI __attribute__((always_inline)) static inline |
| #else |
| #define SI static inline |
| #endif |
| |
| |
| template <typename T, typename P> |
| SI T unaligned_load(const P* p) { // const void* would work too, but const P* helps ARMv7 codegen. |
| T v; |
| memcpy(&v, p, sizeof(v)); |
| return v; |
| } |
| |
| template <typename T, typename P> |
| SI void unaligned_store(P* p, T v) { |
| memcpy(p, &v, sizeof(v)); |
| } |
| |
| template <typename Dst, typename Src> |
| SI Dst bit_cast(const Src& src) { |
| static_assert(sizeof(Dst) == sizeof(Src), ""); |
| return unaligned_load<Dst>(&src); |
| } |
| |
| template <typename Dst, typename Src> |
| SI Dst widen_cast(const Src& src) { |
| static_assert(sizeof(Dst) > sizeof(Src), ""); |
| Dst dst; |
| memcpy(&dst, &src, sizeof(Src)); |
| return dst; |
| } |
| |
| // Our program is an array of void*, either |
| // - 1 void* per stage with no context pointer, the next stage; |
| // - 2 void* per stage with a context pointer, first the context pointer, then the next stage. |
| |
| // load_and_inc() steps the program forward by 1 void*, returning that pointer. |
| SI void* load_and_inc(void**& program) { |
| #if defined(__GNUC__) && defined(__x86_64__) |
| // If program is in %rsi (we try to make this likely) then this is a single instruction. |
| void* rax; |
| asm("lodsq" : "=a"(rax), "+S"(program)); // Write-only %rax, read-write %rsi. |
| return rax; |
| #else |
| // On ARM *program++ compiles into pretty ideal code without any handholding. |
| return *program++; |
| #endif |
| } |
| |
| // LazyCtx doesn't do anything unless you call operator T*(), encapsulating the logic |
| // from above that stages without a context pointer are represented by just 1 void*. |
| struct LazyCtx { |
| void* ptr; |
| void**& program; |
| |
| explicit LazyCtx(void**& p) : ptr(nullptr), program(p) {} |
| |
| template <typename T> |
| operator T*() { |
| if (!ptr) { ptr = load_and_inc(program); } |
| return (T*)ptr; |
| } |
| }; |
| |
| #endif//SkJumper_misc_DEFINED |