/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * -----------------------------------------------------------------------------
 * File: Simd.h
 * Description:
 *  This file implements the function for detecting SIMD support.
 * 
 * Author: Mineplay
 * -----------------------------------------------------------------------------
 */
#include "../../Include/Hallocy/Utils/Simd.h"

HallocySimdType hallocy_is_simd_supported(void) {
    static HallocySimdType hallocy_supported_simd = HALLOCY_SIMD_UNDEFINED;
    if (hallocy_supported_simd != HALLOCY_SIMD_UNDEFINED) {
        return hallocy_supported_simd;
    }

    #if defined(_MSC_VER)
        #if defined(_M_ARM64)
        if (isProcessorFeaturePresent(PF_ARM64_SVE)) {
            hallocy_supported_simd = HALLOCY_SIMD_NEON;
            return hallocy_supported_simd;
        }
        #else
        int cpu_info[4] = { 0 };
        __cpuid(cpu_info, 7);
        if ((cpu_info[1] & (1 << 16)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_AVX512;
            return hallocy_supported_simd;
        }
        
        if ((cpu_info[1] & (1 << 5)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_AVX2;
            return hallocy_supported_simd;
        }

        __cpuid(cpu_info, 1);
        
        if ((cpu_info[2] & (1 << 28)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_AVX;
            return hallocy_supported_simd;
        }

        if ((cpu_info[3] & (1 << 26)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_SSE2;
            return hallocy_supported_simd;
        }

        if ((cpu_info[3] & (1 << 25)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_SSE2;
            return hallocy_supported_simd;
        }
        #endif
    #else
        #if defined(__aarch64__) || defined(__arm__)
        int file_descriptor = open("/proc/cpuinfo", O_READONLY);
        if (file_descriptor == -1) {
            return hallocy_supported_simd;
        }

        char buffer[256];
        int bytes_read = read(file_descriptor, buffer, sizeof(buffer));
        while (bytes_read > 0) {
            for (size_t i = 0; i < bytes_read - 4; i++) {
                if (buffer[i] == 'n' && buffer[i + 1] == 'e' && buffer[i + 2] == 'o' && buffer[i + 3] == 'n') {
                    close(file_descriptor);

                    hallocy_supported_simd = HALLOCY_SIMD_NEON;
                    return hallocy_supported_simd;
                }
            }

            bytes_read = read(file_descriptor, buffer, sizeof(buffer));
        }

        close(file_descriptor);
        #else
        unsigned int a, b, c, d;
        __asm__ __volatile__ (
            "cpuid"
            : "=a" (a), "=b" (b), "=c" (c), "=d" (d)
            : "a" (7)
        );

        if ((b & (1 << 16)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_AVX512;
            return hallocy_supported_simd;
        }

        if ((b & (1 << 5)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_AVX2;
            return hallocy_supported_simd;
        }

        __asm__ __volatile__ (
            "cpuid"
            : "=a" (a), "=b" (b), "=c" (c), "=d" (d)
            : "a" (1)
        );

        if ((c & (1 << 28)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_AVX;
            return hallocy_supported_simd;
        }

        if ((c & (1 << 26)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_SSE2;
            return hallocy_supported_simd;
        }

        if ((c & (1 << 25)) != 0) {
            hallocy_supported_simd = HALLOCY_SIMD_SSE;
            return hallocy_supported_simd;
        }
        #endif
    #endif

    hallocy_supported_simd = HALLOCY_SIMD_NONE;
    return hallocy_supported_simd;
}