JavaCPP Presets for Systems

Introduction

This directory contains the JavaCPP Presets module for system APIs:

• Linux (glibc) https://www.gnu.org/software/libc/
• Mac OS X (XNU libc) https://opensource.apple.com/
• Windows (Win32) https://developer.microsoft.com/en-us/windows/

For now, basic functionality is supported. The range will be expanded based on demand, so please make sure to communicate your needs.

Please refer to the parent README.md file for more detailed information about the JavaCPP Presets.

Documentation

Java API documentation is available here:

• http://bytedeco.org/javacpp-presets/systems/apidocs/

Sample Usage

Here is a simple example to detect some AVX capabilities by using CPUID functions exposed by systems APIs for x86 processors:

• https://en.wikipedia.org/wiki/CPUID

We can use Maven 3 to download and install automatically all the class files as well as the native binaries. To run this sample code, after creating the pom.xml and TestAVX.java source files below, simply execute on the command line:

 $ mvn compile exec:java

The pom.xml build file

<project>
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.bytedeco.systems</groupId>
    <artifactId>testavx</artifactId>
    <version>1.5</version>
    <properties>
        <exec.mainClass>TestAVX</exec.mainClass>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.bytedeco</groupId>
            <artifactId>systems-platform</artifactId>
            <version>1.5</version>
        </dependency>
    </dependencies>
    <build>
        <sourceDirectory>.</sourceDirectory>
    </build>
</project>

The TestAVX.java source file

import org.bytedeco.javacpp.*;
import org.bytedeco.systems.global.*;

public class TestAVX {
    public static void main(String[] args) {
        int AVXbit = 0x10000000;
        int AVX2bit = 0x20;
        boolean hasAVX = false;
        boolean hasAVX2 = false;
        String platform = Loader.getPlatform();

        if (platform.startsWith("linux-x86")) {
            int[] eax = {0}, ebx = {0}, ecx = {0}, edx = {0};
            linux.__cpuid_count(1, 0, eax, ebx, ecx, edx);
            hasAVX = (ecx[0] & AVXbit) != 0;
            linux.__cpuid_count(7, 0, eax, ebx, ecx, edx);
            hasAVX2 = hasAVX && (ebx[0] & AVX2bit) != 0;
        } else if (platform.startsWith("macosx-x86")) {
            int[] eax = {0}, ebx = {0}, ecx = {0}, edx = {0};
            macosx.__cpuid_count(1, 0, eax, ebx, ecx, edx);
            hasAVX = (ecx[0] & AVXbit) != 0;
            macosx.__cpuid_count(7, 0, eax, ebx, ecx, edx);
            hasAVX2 = hasAVX && (ebx[0] & AVX2bit) != 0;
        } else if (platform.startsWith("windows-x86")) {
            int[] cpuinfo = new int[4];
            windows.__cpuidex(cpuinfo, 1, 0);
            hasAVX = (cpuinfo[2] & AVXbit) != 0;
            windows.__cpuidex(cpuinfo, 7, 0);
            hasAVX2 = hasAVX && (cpuinfo[1] & AVX2bit) != 0;
        }

        System.out.println("hasAVX = " + hasAVX);
        System.out.println("hasAVX2 = " + hasAVX2);
    }
}