use crate::Sysno;

use core::sync::atomic::{AtomicBool, Ordering};

static mut HAS_SCV: AtomicBool = AtomicBool::new(false);

macro_rules! sys {
    ($($tt:tt)+) => {
        if HAS_SCV.load(Ordering::SeqCst) {
            // It's `scv 0` instruction but apparently llvm doesn't support it
            ::core::arch::asm!(
                ".byte 0x44",
                ".byte 0x00",
                ".byte 0x00",
                ".byte 0x01",
                $($tt)+
            );
        } else {
            ::core::arch::asm!(
                "sc",
                "bns 0f",
                "neg 3, 3",
                "0:",
                $($tt)+
            );
        }
    };
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall0(sysno: Sysno) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        lateout("r3") ret,
        lateout("r4") _,
        lateout("r5") _,
        lateout("r6") _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags, readonly)

    );
    ret
}

pub use raw_syscall0 as raw_syscall0_readonly;

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall1(sysno: Sysno, arg0: usize) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        lateout("r4") _,
        lateout("r5") _,
        lateout("r6") _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall1_readonly(sysno: Sysno, arg0: usize) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        lateout("r4") _,
        lateout("r5") _,
        lateout("r6") _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags, readonly)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn syscall1_noreturn(sysno: Sysno, arg0: usize) -> ! {
    ::core::arch::asm!(
        "sc",
        "trap",
        in("r0") sysno as usize,
        in("r3") arg0,
        options(noreturn)
    );
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall2(sysno: Sysno, arg0: usize, arg1: usize) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        lateout("r5") _,
        lateout("r6") _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall2_readonly(sysno: Sysno, arg0: usize, arg1: usize) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        lateout("r5") _,
        lateout("r6") _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags, readonly)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall3(sysno: Sysno, arg0: usize, arg1: usize, arg2: usize) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        inlateout("r5") arg2 => _,
        lateout("r6") _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall3_readonly(sysno: Sysno, arg0: usize, arg1: usize, arg2: usize) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        inlateout("r5") arg2 => _,
        lateout("r6") _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags, readonly)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall4(
    sysno: Sysno,
    arg0: usize,
    arg1: usize,
    arg2: usize,
    arg3: usize,
) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        inlateout("r5") arg2 => _,
        inlateout("r6") arg3 => _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall4_readonly(
    sysno: Sysno,
    arg0: usize,
    arg1: usize,
    arg2: usize,
    arg3: usize,
) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        inlateout("r5") arg2 => _,
        inlateout("r6") arg3 => _,
        lateout("r7") _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags, readonly)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall5(
    sysno: Sysno,
    arg0: usize,
    arg1: usize,
    arg2: usize,
    arg3: usize,
    arg4: usize,
) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        inlateout("r5") arg2 => _,
        inlateout("r6") arg3 => _,
        inlateout("r7") arg4 => _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall5_readonly(
    sysno: Sysno,
    arg0: usize,
    arg1: usize,
    arg2: usize,
    arg3: usize,
    arg4: usize,
) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        inlateout("r5") arg2 => _,
        inlateout("r6") arg3 => _,
        inlateout("r7") arg4 => _,
        lateout("r8") _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags, readonly)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall6(
    sysno: Sysno,
    arg0: usize,
    arg1: usize,
    arg2: usize,
    arg3: usize,
    arg4: usize,
    arg5: usize,
) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        inlateout("r5") arg2 => _,
        inlateout("r6") arg3 => _,
        inlateout("r7") arg4 => _,
        inlateout("r8") arg5 => _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags)
    );
    ret
}

#[allow(clippy::missing_safety_doc)]
#[inline(always)]
pub unsafe fn raw_syscall6_readonly(
    sysno: Sysno,
    arg0: usize,
    arg1: usize,
    arg2: usize,
    arg3: usize,
    arg4: usize,
    arg5: usize,
) -> usize {
    let ret;
    sys!(
        inlateout("r0") sysno as usize => _,
        inlateout("r3") arg0 => ret,
        inlateout("r4") arg1 => _,
        inlateout("r5") arg2 => _,
        inlateout("r6") arg3 => _,
        inlateout("r7") arg4 => _,
        inlateout("r8") arg5 => _,
        lateout("r9") _,
        lateout("r10") _,
        lateout("r11") _,
        lateout("r12") _,
        lateout("cr0") _,
        options(nostack, preserves_flags, readonly)
    );
    ret
}

include!("_syscalls.rs");

pub(crate) unsafe fn init() {
    if crate::env::aux::get::<crate::env::aux::HardwareCapabilities2>().map_or(false, |flags| {
        flags.contains(crate::env::aux::Features2::SCV)
    }) {
        HAS_SCV.store(true, Ordering::SeqCst);
    }
}

pub fn has_scv() -> bool {
    unsafe { HAS_SCV.load(Ordering::SeqCst) }
}