v86/src/rust/cpu_context.rs

use cpu;
use prefix::{PREFIX_MASK_ADDRSIZE, PREFIX_MASK_OPSIZE};
use state_flags::CachedStateFlags;

#[derive(Clone)]
pub struct CpuContext {
    pub eip: u32,
    pub prefixes: u32,
    pub cs_offset: u32,
    pub state_flags: CachedStateFlags,
}

impl CpuContext {
    pub fn advance8(&mut self) {
        assert!(self.eip & 0xFFF < 0xFFF);
        self.eip += 1;
    }
    pub fn advance16(&mut self) {
        assert!(self.eip & 0xFFF < 0xFFE);
        self.eip += 2;
    }
    pub fn advance32(&mut self) {
        assert!(self.eip & 0xFFF < 0xFFC);
        self.eip += 4;
    }
    #[allow(unused)]
    pub fn advance_moffs(&mut self) {
        if self.asize_32() {
            self.advance32()
        }
        else {
            self.advance16()
        }
    }

    pub fn read_imm8(&mut self) -> u8 {
        assert!(self.eip & 0xFFF < 0xFFF);
        let v = cpu::read8(self.eip);
        self.eip += 1;
        v
    }
    pub fn read_imm8s(&mut self) -> i8 { self.read_imm8() as i8 }
    pub fn read_imm16(&mut self) -> u16 {
        assert!(self.eip & 0xFFF < 0xFFE);
        let v = cpu::read16(self.eip);
        self.eip += 2;
        v
    }
    pub fn read_imm16s(&mut self) -> i16 { self.read_imm16() as i16 }
    pub fn read_imm32(&mut self) -> u32 {
        assert!(self.eip & 0xFFF < 0xFFC);
        let v = cpu::read32(self.eip);
        self.eip += 4;
        v
    }
    pub fn read_moffs(&mut self) -> u32 {
        if self.asize_32() {
            self.read_imm32()
        }
        else {
            self.read_imm16() as u32
        }
    }

    pub fn cpl3(&self) -> bool { self.state_flags.cpl3() }
    pub fn has_flat_segmentation(&self) -> bool { self.state_flags.has_flat_segmentation() }
    pub fn osize_32(&self) -> bool {
        self.state_flags.is_32() != (self.prefixes & PREFIX_MASK_OPSIZE != 0)
    }
    pub fn asize_32(&self) -> bool {
        self.state_flags.is_32() != (self.prefixes & PREFIX_MASK_ADDRSIZE != 0)
    }
    pub fn ssize_32(&self) -> bool { self.state_flags.ssize_32() }
}