emu: factor out operations and operands into own module

src/emu/i8088.rs

@@ -3,6 +3,8 @@ use std::fmt::{Debug, Formatter};
 
 use super::byteorder::{ByteOrder, LittleEndian};
 
+use emu::operands::{Addr, Reg, RegHi};
+use emu::operations as ops;
 use emu::pc::Bus;
 
 #[allow(non_camel_case_types)]
@@ -50,156 +52,6 @@ pub struct Flags {
   // bits 12-15 always 1
 }
 
-mod ops {
-  use emu::byteorder::{ByteOrder, LittleEndian};
-  use emu::dos;
-  use emu::i8088::{Address, Bus, LValue, Reg, RValue, i8088, segoff_to_addr};
-
-  pub fn show(cpu: &mut i8088) {
-    println!("{:#X?}", cpu);
-  }
-
-  pub fn peek(addr: &(impl Address + RValue<u8>)) {
-    println!("PEEK: @{:#X} = {:#X} ({})", addr.addr(), addr.read(), addr.read());
-  }
-
-  pub fn call(ip: &mut Reg, ss: u16, sp: &mut Reg, mem: &mut [u8], addr: i16) {
-    let target = ip.read().wrapping_add(addr as u16);
-    push16(ss, sp, mem, ip.read());
-    ip.write(target);
-  }
-
-  pub fn int(cpu: &mut i8088, bus: &mut Bus, num: &u8) {
-    match num {
-      0x21 => dos::interrupt(cpu, bus),
-      _ => unimplemented!("interrupt: {:02X}\ncpu: {:#X?}", num, cpu)
-    }
-  }
-
-  pub fn mov<T>(dst: &mut impl LValue<T>, src: &impl RValue<T>) {
-    dst.write(src.read());
-  }
-
-  pub fn nop() {}
-
-  pub fn pop16(ss: u16, sp: &mut Reg, mem: &[u8]) -> u16 {
-    let val = LittleEndian::read_u16(&mem[segoff_to_addr(ss.read(), sp.read())..]);
-    sp.write(sp.read() + 2);
-    val
-  }
-
-  pub fn push16(ss: u16, sp: &mut Reg, mem: &mut [u8], val: u16) {
-    // XXX: Not checking for stack faults or anything
-    sp.write(sp.read() - 2);
-    LittleEndian::write_u16(&mut mem[segoff_to_addr(ss.read(), sp.read())..], val);
-  }
-
-  pub fn ret(ip: &mut Reg, ss: u16, sp: &mut Reg, mem: &[u8]) {
-    ip.write(pop16(ss, sp, mem));
-  }
-}
-
-pub trait LValue<T> {
-  fn write(&mut self, val: T);
-}
-
-pub trait RValue<T> {
-  fn read(&self) -> T;
-}
-
-pub trait Address {
-  fn addr(&self) -> usize;
-}
-
-impl RValue<u8> for u8 {
-  fn read(&self) -> u8 {
-    *self
-  }
-}
-
-impl LValue<u16> for u16 {
-  fn write(&mut self, val: u16) {
-    *self = val;
-  }
-}
-
-impl RValue<u16> for u16 {
-  fn read(&self) -> u16 {
-    *self
-  }
-}
-
-pub struct Reg<'a> {
-  reg: &'a Cell<u16>
-}
-
-impl LValue<u16> for Reg<'_> {
-  fn write(&mut self, val: u16) {
-    self.reg.set(val);
-  }
-}
-
-impl RValue<u16> for Reg<'_> {
-  fn read(&self) -> u16 {
-    self.reg.get()
-  }
-}
-
-struct RegHi<'a> {
-  reg: &'a Cell<u16>
-}
-
-impl LValue<u8> for RegHi<'_> {
-  fn write(&mut self, val: u8) {
-    write_hi(&mut self.reg, val);
-  }
-}
-
-impl RValue<u8> for RegHi<'_> {
-  fn read(&self) -> u8 {
-    read_hi(self.reg)
-  }
-}
-
-struct Addr<'a> {
-  bus: &'a mut Bus,
-  addr: usize
-}
-
-impl Address for Addr<'_> {
-  fn addr(&self) -> usize {
-    self.addr
-  }
-}
-
-impl LValue<u8> for Addr<'_> {
-  fn write(&mut self, val: u8) {
-    self.bus.write(self.addr, val);
-  }
-}
-
-impl RValue<u8> for Addr<'_> {
-  fn read(&self) -> u8 {
-    self.bus.read(self.addr)
-  }
-}
-
-struct RegLo<'a> {
-  reg: &'a Cell<u16>
-}
-
-impl LValue<u8> for RegLo<'_> {
-  fn write(&mut self, val: u8) {
-    write_lo(&mut self.reg, val);
-  }
-}
-
-impl RValue<u8> for RegLo<'_> {
-  fn read(&self) -> u8 {
-    read_lo(self.reg)
-  }
-}
-
 macro_rules! step {
   // Base case: all args processed and ready to call op
   (@code ( $($done:tt)* ),
@@ -384,37 +236,6 @@ macro_rules! step {
   }
 }
 
-pub const fn segoff_to_addr(segment: u16, offset: u16) -> usize {
-  let segaddr = (segment as usize) << 4;
-  segaddr + offset as usize
-}
-
-pub fn read_hi(val: &Cell<u16>) -> u8 {
-  let mut buf = [0; 2];
-  LittleEndian::write_u16(&mut buf, val.get());
-  buf[1] as u8
-}
-
-pub fn read_lo(val: &Cell<u16>) -> u8 {
-  let mut buf = [0; 2];
-  LittleEndian::write_u16(&mut buf, val.get());
-  buf[0] as u8
-}
-
-pub fn write_hi(reg: &Cell<u16>, val: u8) {
-  let mut buf = [0; 2];
-  LittleEndian::write_u16(&mut buf, reg.get());
-  buf[1] = val;
-  reg.set(LittleEndian::read_u16(&buf))
-}
-
-pub fn write_lo(reg: &Cell<u16>, val: u8) {
-  let mut buf = [0; 2];
-  LittleEndian::write_u16(&mut buf, reg.get());
-  buf[1] = val;
-  reg.set(LittleEndian::read_u16(&buf));
-}
-
 impl i8088 {
   pub fn run(&mut self, bus: &mut Bus) {
     loop {
@@ -481,6 +302,36 @@ impl i8088 {
   }
 }
 
+pub const fn segoff_to_addr(segment: u16, offset: u16) -> usize {
+  let segaddr = (segment as usize) << 4;
+  segaddr + offset as usize
+}
+
+pub fn read_hi(val: &Cell<u16>) -> u8 {
+  let mut buf = [0; 2];
+  LittleEndian::write_u16(&mut buf, val.get());
+  buf[1] as u8
+}
+
+pub fn read_lo(val: &Cell<u16>) -> u8 {
+  let mut buf = [0; 2];
+  LittleEndian::write_u16(&mut buf, val.get());
+  buf[0] as u8
+}
+
+pub fn write_hi(reg: &Cell<u16>, val: u8) {
+  let mut buf = [0; 2];
+  LittleEndian::write_u16(&mut buf, reg.get());
+  buf[1] = val;
+  reg.set(LittleEndian::read_u16(&buf))
+}
+
+pub fn write_lo(reg: &Cell<u16>, val: u8) {
+  let mut buf = [0; 2];
+  LittleEndian::write_u16(&mut buf, reg.get());
+  buf[1] = val;
+  reg.set(LittleEndian::read_u16(&buf));
+}
 
 impl From<u16> for Flags {
   fn from(flags: u16) -> Self {