use core::intrinsics;

// NOTE This function and the one below are implemented using assembly because they using a custom
// calling convention which can't be implemented using a normal Rust function
#[naked]
#[cfg_attr(not(test), no_mangle)]
pub unsafe fn __aeabi_uidivmod() {
    asm!("push {lr}
          sub sp, sp, #4
          mov r2, sp
          bl __udivmodsi4
          ldr r1, [sp], #4
          pop {pc}");
    intrinsics::unreachable();
}

#[naked]
#[cfg_attr(not(test), no_mangle)]
pub unsafe fn __aeabi_uldivmod() {
    asm!("push {lr}
          sub r12, sp, #12
          str r12, [sp, #-20]!
          bl __udivmoddi4
          ldrd r2, r3, [sp, #8]
          add sp, sp, #20
          pop {pc}");
    intrinsics::unreachable();
}

extern "C" {
    fn memcpy(dest: *mut u8, src: *const u8, n: usize) -> *mut u8;
    fn memmove(dest: *mut u8, src: *const u8, n: usize) -> *mut u8;
    fn memset(dest: *mut u8, c: i32, n: usize) -> *mut u8;
}

// FIXME: The `*4` and `*8` variants should be defined as aliases.

#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memcpy(dest: *mut u8, src: *const u8, n: usize) {
    memcpy(dest, src, n);
}
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memcpy4(dest: *mut u8, src: *const u8, n: usize) {
    memcpy(dest, src, n);
}
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memcpy8(dest: *mut u8, src: *const u8, n: usize) {
    memcpy(dest, src, n);
}

#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memmove(dest: *mut u8, src: *const u8, n: usize) {
    memmove(dest, src, n);
}
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memmove4(dest: *mut u8, src: *const u8, n: usize) {
    memmove(dest, src, n);
}
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memmove8(dest: *mut u8, src: *const u8, n: usize) {
    memmove(dest, src, n);
}

// Note the different argument order
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memset(dest: *mut u8, n: usize, c: i32) {
    memset(dest, c, n);
}
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memset4(dest: *mut u8, n: usize, c: i32) {
    memset(dest, c, n);
}
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memset8(dest: *mut u8, n: usize, c: i32) {
    memset(dest, c, n);
}

#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memclr(dest: *mut u8, n: usize) {
    memset(dest, 0, n);
}
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memclr4(dest: *mut u8, n: usize) {
    memset(dest, 0, n);
}
#[cfg_attr(not(test), no_mangle)]
pub unsafe extern "C" fn __aeabi_memclr8(dest: *mut u8, n: usize) {
    memset(dest, 0, n);
}