moa/src/cpus/m68k/state.rs

use crate::system::System;
use crate::memory::Address;
use crate::timers::CpuTimer;

use super::decode::M68kDecoder;
use super::debugger::M68kDebugger;


#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub enum M68kType {
    MC68000,
    MC68010,
    MC68020,
    MC68030,
}

const FLAGS_ON_RESET: u16 = 0x2700;

#[repr(u16)]
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum Flags {
    Carry       = 0x0001,
    Overflow    = 0x0002,
    Zero        = 0x0004,
    Negative    = 0x0008,
    Extend      = 0x0010,
    IntMask     = 0x0700,
    Interrupt   = 0x1000,
    Supervisor  = 0x2000,
    Tracing     = 0x8000,
}

pub const ERR_BUS_ERROR: u32 = 2;
pub const ERR_ADDRESS_ERROR: u32 = 3;
pub const ERR_ILLEGAL_INSTRUCTION: u32 = 4;


#[derive(Copy, Clone, Debug, PartialEq)]
pub enum Status {
    Init,
    Running,
    Stopped,
    Halted,
}

#[repr(u8)]
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum InterruptPriority {
    NoInterrupt = 0,
    Level1 = 1,
    Level2 = 2,
    Level3 = 3,
    Level4 = 4,
    Level5 = 5,
    Level6 = 6,
    Level7 = 7,
}

impl InterruptPriority {
    pub fn from_u8(priority: u8) -> InterruptPriority {
        match priority {
            0 => InterruptPriority::NoInterrupt,
            1 => InterruptPriority::Level1,
            2 => InterruptPriority::Level2,
            3 => InterruptPriority::Level3,
            4 => InterruptPriority::Level4,
            5 => InterruptPriority::Level5,
            6 => InterruptPriority::Level6,
            _ => InterruptPriority::Level7,
        }
    }
}

pub struct M68kState {
    pub status: Status,
    pub current_ipl: InterruptPriority,
    pub pending_ipl: InterruptPriority,
    pub ipl_ack_num: u8,

    pub pc: u32,
    pub sr: u16,
    pub d_reg: [u32; 8],
    pub a_reg: [u32; 7],
    pub msp: u32,
    pub usp: u32,

    pub vbr: u32,
}

impl M68kState {
    pub fn new() -> M68kState {
        M68kState {
            status: Status::Init,
            current_ipl: InterruptPriority::NoInterrupt,
            pending_ipl: InterruptPriority::NoInterrupt,
            ipl_ack_num: 0,

            pc: 0,
            sr: FLAGS_ON_RESET,
            d_reg: [0; 8],
            a_reg: [0; 7],
            msp: 0,
            usp: 0,

            vbr: 0,
        }
    }
}

pub struct M68k {
    pub cputype: M68kType,
    pub state: M68kState,
    pub decoder: M68kDecoder,
    pub debugger: M68kDebugger,
    pub timer: CpuTimer,
}

impl M68k {
    pub fn new(cputype: M68kType) -> M68k {
        M68k {
            cputype,
            state: M68kState::new(),
            decoder: M68kDecoder::new(cputype, 0, 0),
            debugger: M68kDebugger::new(),
            timer: CpuTimer::new(),
        }
    }

    pub fn reset(&mut self) {
        self.state = M68kState::new();
        self.decoder = M68kDecoder::new(self.cputype, 0, 0);
        self.debugger = M68kDebugger::new();
    }

    pub fn dump_state(&self, system: &System) {
        println!("Status: {:?}", self.state.status);
        println!("PC: {:#010x}", self.state.pc);
        println!("SR: {:#06x}", self.state.sr);
        for i in 0..7 {
            println!("D{}: {:#010x}        A{}:  {:#010x}", i, self.state.d_reg[i as usize], i, self.state.a_reg[i as usize]);
        }
        println!("D7: {:#010x}", self.state.d_reg[7]);
        println!("MSP: {:#010x}", self.state.msp);
        println!("USP: {:#010x}", self.state.usp);

        println!("Current Instruction: {:#010x} {:?}", self.decoder.start, self.decoder.instruction);
        println!("");
        system.get_bus().dump_memory(self.state.msp as Address, 0x40);
        println!("");
    }
}