use riscv::register::sstatus::{self, Sstatus, SPP};

#[repr(C)]
pub struct TrapContext {
    pub x: [usize; 32],
    pub s_status: Sstatus,
    pub sepc: usize,
}

impl TrapContext {
    pub fn init_application_context(entry: usize, sp: usize) -> Self {
        let sstatus = sstatus::read();
        unsafe {
            sstatus::set_spp(SPP::User);
        }
        let mut context = Self {
            x: [0; 32],
            s_status: sstatus,
            sepc: entry,
        };

        context.set_sp(sp);
        context
    }

    pub fn set_sp(&mut self, sp: usize) {
        // x2 is stack pointer register
        self.x[2] = sp;
    }
}