Inline assembly¶

One of the distinctive parts of Novus is that low-level work happens inside the language rather than through a separate FFI layer for every platform.

This is mainly useful for:

syscalls
register manipulation
tiny platform backends
Windows API calls via win_call

Most application code should still prefer std and existing libraries.

The core builtins¶

Builtin	What it does
`mov(reg, value)`	load a value into a register
`getreg(reg)`	read a register value
`syscall()`	issue a syscall on Unix-like targets
`ptr(value)`	get the address of a value
`push(value)` / `pop()`	direct stack operations
`win_call("Name", ...)`	call a Windows API symbol

A tiny register example¶

fn read_back_demo() -> u64 {
    mov(x0, 42);
    return getreg(x0);
}

This does not do any OS work. It just proves that Novus can place and read values directly from registers.

A syscall-shaped example¶

The exact syscall numbers are platform-specific, but the structure is always the same:

fn raw_write(fd: i32, buf: str) -> u64 {
    mov(x0, fd);
    mov(x1, ptr(buf));
    mov(x2, len(buf));
    mov(x16, 0x2000000 + 4);
    syscall();
    return getreg(x0);
}

That is the general pattern used in many Novus low-level libraries:

load arguments into the correct registers
load the syscall number
call syscall()
read the result with getreg(...)

Windows API calls¶

On Windows, Novus libraries often use win_call instead of syscall.

win_call("ExitProcess", 0);

This pattern appears in platform-specific code such as terminal or environment helpers.

Conditional compilation matters¶

Inline assembly is usually wrapped in #if blocks:

#if(os == "darwin") {
    mov(x16, 0x2000000 + 4);
    syscall();
}

#if(os == "windows") {
    win_call("ExitProcess", 0);
}

That is the normal way to keep one public API while swapping implementations per OS or architecture.

When to reach for inline assembly¶

Use it when you are:

building a library backend
wrapping a platform syscall directly
exposing a missing low-level primitive

Do not use it for everyday string handling, arrays, printing, file IO, or process launching if an official library already does that work.

Best place to learn from real code¶

Study these sources:

official Novus docs and legacy docs
novus-window
novus-env
novus-process
examples/lib/term/main.nov in the Novus repo