calling conventions

main.rs

#[cfg(unix)]
std::arch::global_asm!(
    "with_rsp:",
    "xor rax, rax",
    "add rax, rdi",
    "shl rsi, 1",
    "add rax, rsi",
    "shl rdx, 2",
    "add rax, rdx",
    "shl rcx, 3",
    "add rax, rcx",
    "add rax, r8",
    "add rax, r9",
    "add rax, [rsp + 8]",
    "add rax, [rsp + 16]",
    "ret",
    "with_rbp:",
    "push rbp",
    "mov rbp, rsp",
    "xor rax, rax",
    "add rax, rdi",
    "shl rsi, 1",
    "add rax, rsi",
    "shl rdx, 2",
    "add rax, rdx",
    "shl rcx, 3",
    "add rax, rcx",
    "add rax, r8",
    "add rax, r9",
    "add rax, [rbp + 16]",
    "add rax, [rbp + 24]",
    "pop rbp",
    "ret",
);

#[cfg(windows)]
std::arch::global_asm!(
    "with_rsp:",
    "xor rax, rax",
    "add rax, rdx",
    "shl rcx, 1",
    "add rax, rcx",
    "shl r8, 2",
    "add rax, r8",
    "shl r9, 3",
    "add rax, r9",
    "add rax, [rsp + 40]",
    "add rax, [rsp + 48]",
    "add rax, [rsp + 56]",
    "add rax, [rsp + 64]",
    "ret",
    "with_rbp:",
    "push rbp",
    "mov rbp, rsp",
    "xor rax, rax",
    "add rax, rdx",
    "shl rcx, 1",
    "add rax, rcx",
    "shl r8, 2",
    "add rax, r8",
    "shl r9, 3",
    "add rax, r9",
    "add rax, [rbp + 48]",
    "add rax, [rbp + 56]",
    "add rax, [rbp + 64]",
    "add rax, [rbp + 72]",
    "pop rbp",
    "ret",
);

extern "C" {
    #[cfg(unix)]
    fn with_rsp(
        arg1: u64,
        arg2: u64,
        arg3: u64,
        arg4: u64,
        arg5: u64,
        arg6: u64,
        arg7: u64,
        arg8: u64,
    ) -> u64;
    #[cfg(unix)]
    fn with_rbp(
        arg1: u64,
        arg2: u64,
        arg3: u64,
        arg4: u64,
        arg5: u64,
        arg6: u64,
        arg7: u64,
        arg8: u64,
    ) -> u64;
    #[cfg(windows)]
    fn with_rsp(
        arg1: u64,
        arg2: u64,
        arg3: u64,
        arg4: u64,
        arg5: u64,
        arg6: u64,
        arg7: u64,
        arg8: u64,
    ) -> u64;
    #[cfg(windows)]
    fn with_rbp(
        arg1: u64,
        arg2: u64,
        arg3: u64,
        arg4: u64,
        arg5: u64,
        arg6: u64,
        arg7: u64,
        arg8: u64,
    ) -> u64;
}

fn main() {
    unsafe {
        println!("rsp: {}", with_rsp(1, 1, 1, 1, 16, 32, 64, 128));
        println!("rbp: {}", with_rbp(1, 1, 1, 1, 16, 32, 64, 128));
    }
}