Assembler Functions

An asm func body is written directly in assembly for the build target instead of Rux. Use it when exact instruction-level control is required:

asm func Greet() {
    mov eax, 4      // 'write' system call
    mov ebx, 1      // file descriptor (stdout)
    mov ecx, msg    // pointer to the string
    mov edx, len    // length of the string
    int 0x80        // call the kernel

    mov eax, 1      // 'exit' system call
    xor ebx, ebx    // return code 0
    int 0x80        // call the kernel
}

The instruction set is that of the build target, so an asm func is inherently platform-specific — pair it with @[Target] when a package supports more than one architecture.

See Also

• Function Declaration — ordinary Rux-bodied functions
• @[Target] — restricting a function to one platform
• Foreign Function Interface — calling external native code instead