/*

 * Copyright 2016 Google Inc.

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#include "include/core/SkStream.h"

#include "include/core/SkString.h"

#include "include/private/SkOnce.h"

#include "src/core/SkCpu.h"

#if defined(SK_CPU_X86)

    #if defined(_MSC_VER)

        #include <intrin.h>

        static void cpuid (uint32_t abcd[4]) { __cpuid  ((int*)abcd, 1);    }

        static void cpuid7(uint32_t abcd[4]) { __cpuidex((int*)abcd, 7, 0); }

        static uint64_t xgetbv(uint32_t xcr) { return _xgetbv(xcr); }

    #else

        #include <cpuid.h>

        #if !defined(__cpuid_count)  // Old Mac Clang doesn't have this defined.

            #define  __cpuid_count(eax, ecx, a, b, c, d) \

                __asm__("cpuid" : "=a"(a), "=b"(b), "=c"(c), "=d"(d) : "0"(eax), "2"(ecx))

        #endif

        static void cpuid (uint32_t abcd[4]) { __get_cpuid(1, abcd+0, abcd+1, abcd+2, abcd+3); }

        static void cpuid7(uint32_t abcd[4]) {

            __cpuid_count(7, 0, abcd[0], abcd[1], abcd[2], abcd[3]);

        }

        static uint64_t xgetbv(uint32_t xcr) {

            uint32_t eax, edx;

            __asm__ __volatile__ ( "xgetbv" : "=a"(eax), "=d"(edx) : "c"(xcr));

            return (uint64_t)(edx) << 32 | eax;

        }

    #endif

    static uint32_t read_cpu_features() {

        uint32_t features = 0;

        uint32_t abcd[4] = {0,0,0,0};

        // You might want to refer to http://www.sandpile.org/x86/cpuid.htm

        cpuid(abcd);

        if (abcd[3] & (1<<25)) { features |= SkCpu:: SSE1; }

        if (abcd[3] & (1<<26)) { features |= SkCpu:: SSE2; }

        if (abcd[2] & (1<< 0)) { features |= SkCpu:: SSE3; }

        if (abcd[2] & (1<< 9)) { features |= SkCpu::SSSE3; }

        if (abcd[2] & (1<<19)) { features |= SkCpu::SSE41; }

        if (abcd[2] & (1<<20)) { features |= SkCpu::SSE42; }

        if ((abcd[2] & (3<<26)) == (3<<26)         // XSAVE + OSXSAVE

             && (xgetbv(0) & (3<<1)) == (3<<1)) {  // XMM and YMM state enabled.

            if (abcd[2] & (1<<28)) { features |= SkCpu:: AVX; }

            if (abcd[2] & (1<<29)) { features |= SkCpu::F16C; }

            if (abcd[2] & (1<<12)) { features |= SkCpu:: FMA; }

            cpuid7(abcd);

            if (abcd[1] & (1<<5)) { features |= SkCpu::AVX2; }

            if (abcd[1] & (1<<3)) { features |= SkCpu::BMI1; }

            if (abcd[1] & (1<<8)) { features |= SkCpu::BMI2; }

            if (abcd[1] & (1<<9)) { features |= SkCpu::ERMS; }

            if ((xgetbv(0) & (7<<5)) == (7<<5)) {  // All ZMM state bits enabled too.

                if (abcd[1] & (1<<16)) { features |= SkCpu::AVX512F; }

                if (abcd[1] & (1<<17)) { features |= SkCpu::AVX512DQ; }

                if (abcd[1] & (1<<21)) { features |= SkCpu::AVX512IFMA; }

                if (abcd[1] & (1<<26)) { features |= SkCpu::AVX512PF; }

                if (abcd[1] & (1<<27)) { features |= SkCpu::AVX512ER; }

                if (abcd[1] & (1<<28)) { features |= SkCpu::AVX512CD; }

                if (abcd[1] & (1<<30)) { features |= SkCpu::AVX512BW; }

                if (abcd[1] & (1<<31)) { features |= SkCpu::AVX512VL; }

            }

        }

        return features;

    }

#elif defined(SK_CPU_ARM64) && __has_include(<sys/auxv.h>)

    #include <sys/auxv.h>

    static uint32_t read_cpu_features() {

        const uint32_t kHWCAP_CRC32   = (1<< 7),

                       kHWCAP_ASIMDHP = (1<<10);

        uint32_t features = 0;

        uint32_t hwcaps = getauxval(AT_HWCAP);

        if (hwcaps & kHWCAP_CRC32  ) { features |= SkCpu::CRC32; }

        if (hwcaps & kHWCAP_ASIMDHP) { features |= SkCpu::ASIMDHP; }

        // The Samsung Mongoose 3 core sets the ASIMDHP bit but doesn't support it.

        for (int core = 0; features & SkCpu::ASIMDHP; core++) {

            // These /sys files contain the core's MIDR_EL1 register, the source of

            // CPU {implementer, variant, part, revision} you'd see in /proc/cpuinfo.

            SkString path =

                SkStringPrintf("/sys/devices/system/cpu/cpu%d/regs/identification/midr_el1", core);

            // Can't use SkData::MakeFromFileName() here, I think because /sys can't be mmap()'d.

            SkFILEStream midr_el1(path.c_str());

            if (!midr_el1.isValid()) {

                // This is our ordinary exit path.

                // If we ask for MIDR_EL1 from a core that doesn't exist, we've checked all cores.

                if (core == 0) {

                    // On the other hand, if we can't read MIDR_EL1 from any core, assume the worst.

                    features &= ~(SkCpu::ASIMDHP);

                }

                break;

            }

            const char kMongoose3[] = "0x00000000531f0020";  // 53 == Samsung.

            char buf[SK_ARRAY_COUNT(kMongoose3) - 1];  // No need for the terminating \0.

            if (SK_ARRAY_COUNT(buf) != midr_el1.read(buf, SK_ARRAY_COUNT(buf))

                          || 0 == memcmp(kMongoose3, buf, SK_ARRAY_COUNT(buf))) {

                features &= ~(SkCpu::ASIMDHP);

            }

        }

        return features;

    }

#elif defined(SK_CPU_ARM32) && __has_include(<sys/auxv.h>) && \

    (!defined(__ANDROID_API__) || __ANDROID_API__ >= 18)

    // sys/auxv.h will always be present in the Android NDK due to unified

    //headers, but getauxval is only defined for API >= 18.

    #include <sys/auxv.h>

    static uint32_t read_cpu_features() {

        const uint32_t kHWCAP_NEON  = (1<<12);

        const uint32_t kHWCAP_VFPv4 = (1<<16);

        uint32_t features = 0;

        uint32_t hwcaps = getauxval(AT_HWCAP);

        if (hwcaps & kHWCAP_NEON ) {

            features |= SkCpu::NEON;

            if (hwcaps & kHWCAP_VFPv4) { features |= SkCpu::NEON_FMA|SkCpu::VFP_FP16; }

        }

        return features;

    }

#elif defined(SK_CPU_ARM32) && __has_include(<cpu-features.h>)

    #include <cpu-features.h>

    static uint32_t read_cpu_features() {

        uint32_t features = 0;

        uint64_t cpu_features = android_getCpuFeatures();

        if (cpu_features & ANDROID_CPU_ARM_FEATURE_NEON)     { features |= SkCpu::NEON; }

        if (cpu_features & ANDROID_CPU_ARM_FEATURE_NEON_FMA) { features |= SkCpu::NEON_FMA; }

        if (cpu_features & ANDROID_CPU_ARM_FEATURE_VFP_FP16) { features |= SkCpu::VFP_FP16; }

        return features;

    }

#else

    static uint32_t read_cpu_features() {

        return 0;

    }

#endif

uint32_t SkCpu::gCachedFeatures = 0;

void SkCpu::CacheRuntimeFeatures() {

    static SkOnce once;

    once([] { gCachedFeatures = read_cpu_features(); });

}