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/*
* Copyright 2012 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkUtilsArm_DEFINED
#define SkUtilsArm_DEFINED
#include "SkUtils.h"
// Define SK_ARM_NEON_MODE to one of the following values
// corresponding respectively to:
// - No ARM Neon support at all (not targetting ARMv7-A, or don't have NEON)
// - Full ARM Neon support (i.e. assume the CPU always supports it)
// - Optional ARM Neon support (i.e. probe CPU at runtime)
//
#define SK_ARM_NEON_MODE_NONE 0
#define SK_ARM_NEON_MODE_ALWAYS 1
#define SK_ARM_NEON_MODE_DYNAMIC 2
#if defined(__arm__) && defined(__ARM_HAVE_OPTIONAL_NEON_SUPPORT)
# define SK_ARM_NEON_MODE SK_ARM_NEON_MODE_DYNAMIC
#elif defined(__arm__) && defined(__ARM_HAVE_NEON)
# define SK_ARM_NEON_MODE SK_ARM_NEON_MODE_ALWAYS
#else
# define SK_ARM_NEON_MODE SK_ARM_NEON_MODE_NONE
#endif
// Convenience test macros, always defined as 0 or 1
#define SK_ARM_NEON_IS_NONE (SK_ARM_NEON_MODE == SK_ARM_NEON_MODE_NONE)
#define SK_ARM_NEON_IS_ALWAYS (SK_ARM_NEON_MODE == SK_ARM_NEON_MODE_ALWAYS)
#define SK_ARM_NEON_IS_DYNAMIC (SK_ARM_NEON_MODE == SK_ARM_NEON_MODE_DYNAMIC)
// The sk_cpu_arm_has_neon() function returns true iff the target device
// is ARMv7-A and supports Neon instructions. In DYNAMIC mode, this actually
// probes the CPU at runtime (and caches the result).
#if SK_ARM_NEON_IS_NONE
static bool sk_cpu_arm_has_neon(void) {
return false;
}
#elif SK_ARM_NEON_IS_ALWAYS
static bool sk_cpu_arm_has_neon(void) {
return true;
}
#else // SK_ARM_NEON_IS_DYNAMIC
extern bool sk_cpu_arm_has_neon(void) SK_PURE_FUNC;
#endif
// Use SK_ARM_NEON_WRAP(symbol) to map 'symbol' to a NEON-specific symbol
// when applicable. This will transform 'symbol' differently depending on
// the current NEON configuration, i.e.:
//
// NONE -> 'symbol'
// ALWAYS -> 'symbol_neon'
// DYNAMIC -> 'symbol' or 'symbol_neon' depending on runtime check.
//
// The goal is to simplify user code, for example:
//
// return SK_ARM_NEON_WRAP(do_something)(params);
//
// Replaces the equivalent:
//
// #if SK_ARM_NEON_IS_NONE
// return do_something(params);
// #elif SK_ARM_NEON_IS_ALWAYS
// return do_something_neon(params);
// #elif SK_ARM_NEON_IS_DYNAMIC
// if (sk_cpu_arm_has_neon())
// return do_something_neon(params);
// else
// return do_something(params);
// #endif
//
#if SK_ARM_NEON_IS_NONE
# define SK_ARM_NEON_WRAP(x) (x)
#elif SK_ARM_NEON_IS_ALWAYS
# define SK_ARM_NEON_WRAP(x) (x ## _neon)
#elif SK_ARM_NEON_IS_DYNAMIC
# define SK_ARM_NEON_WRAP(x) (sk_cpu_arm_has_neon() ? x ## _neon : x)
#endif
#endif // SkUtilsArm_DEFINED
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