//! # Wrapping ARMv7-A Instructions
//!
//! This provides bindings for assembly instructions
//! to be used in other rust functions without `unsafe`
//! markers everywhere.

/// # Wait for event
#[inline(always)]
pub fn wfe() {
    unsafe { core::arch::asm!("wfe", options(nomem, nostack)) }
}

/// # No Operation
#[inline(always)]
pub fn nop() {
    unsafe { core::arch::asm!("nop", options(nomem, nostack)) }
}

/// # Store u32 to memory address
#[inline]
pub fn store32(addr: u32, value: u32) {
    unsafe {
        *(addr as *mut u32) = value;
    }
}

/// # Read u32 from memory address
#[inline]
pub fn load32(addr: u32) -> u32 {
    unsafe { *(addr as *mut u32) }
}

/// # Spin CPU for `n` cycles
#[inline]
pub fn spin_for_n_cycles(n: u32) {
    unsafe {
        core::arch::asm!("1: subs r1, #1
				bne 1b", in("r1") n);
    }
}

/// # Switch to user mode
#[inline]
pub fn usr_mode() {
    unsafe {
        core::arch::asm!("cps 0x10");
    }
}