MASM(x64)でdllを作る

Windows 10 Pro (64bit)
Visual Studio 2022 Community

dlltest.asm

comment *
ml64 /c /Fl dlltest.asm
link /dll /entry:DllMain dlltest
*
.code

DllMain proc
    mov eax, 1
    ret
DllMain endp

myadd proc export
    mov rax, rcx
    add rax, rdx
    ret
myadd endp

mysub proc export
    mov rax, rcx
    sub rax, rdx
    ret
mysub endp

end

dev.bat

@echo off
path %path%;C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.30.30705\bin\Hostx64\x64
path %path%;C:\Windows\Microsoft.NET\Framework64\v4.0.30319
cmd

C#でテスト

x64版のcsc.exeにpathを通す。

dlltest.cs

// csc dlltest.cs

using System;
using System.Runtime.InteropServices;

class Program {
    [DllImport("dlltest.dll")]
    static extern int myadd(int a, int b);
    [DllImport("dlltest.dll")]
    static extern int mysub(int a, int b);

    static void Main() {
        Console.WriteLine("add = {0}", myadd(1, 2));
        Console.WriteLine("sub = {0}", mysub(1, 2));
    }
}

実行例

CPUIDサンプル

cpuid.asm

comment *
ml64 /c /Fl cpuid.asm
link /dll /entry:DllMain cpuid
*
.code

DllMain proc
    mov eax, 1
    ret
DllMain endp

getcpuid proc export
    push    rbx
    mov r8, rcx
    mov eax, edx
    cpuid
    mov [r8   ], eax
    mov [r8+ 4], ebx
    mov [r8+ 8], ecx
    mov [r8+12], edx
    pop rbx
    ret
getcpuid endp

end

cpuid.cs

// csc cpuid.cs

using System;
using System.Runtime.InteropServices;
using System.Text;

class Program {
    [DllImport("cpuid.dll")]
    static extern void getcpuid(byte[] p, uint eax);

    static void Main() {
        var ascii = new ASCIIEncoding();
        var b = new byte[16];
        for (uint i = 0; i < 3; i++) {
            getcpuid(b, 0x80000002 + i);
            Console.WriteLine("[{0}]", ascii.GetString(b));
        }
    }
}

出力例

C:\Projects\MASM\cpuid>cpuid
[Intel(R) Celeron]
[(R) N4000 CPU @ ]
[1.10GHz         ]

参考