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added rts isntruction

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Lauchmelder 2022-08-24 02:27:07 +02:00
parent a2695b5ca1
commit 48b76193d2
2 changed files with 26 additions and 6 deletions
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2
src/cpu.rs
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@ -73,6 +73,8 @@ impl CPU
instr_set[0x50] = instr!(bvc, rel, 2, 2);
instr_set[0x60] = instr!(rts, imp, 6, 1);
instr_set[0x70] = instr!(bvs, rel, 2, 2);
instr_set[0x85] = instr!(sta, zpg, 3, 2);

30
src/instructions.rs
View file

@ -1,4 +1,6 @@
use crate::cpu::CPU;
use crate::bus::Bus;
use std::cell::Ref;
#[allow(dead_code)]
enum Bit
@ -52,6 +54,12 @@ macro_rules! push
}
}
fn pop(bus: Ref<Bus>, sp: &mut u8) -> u8
{
*sp += 1;
bus.read_cpu(0x0100 + *sp as u16)
}
macro_rules! branch
{
($self: ident) =>
@ -70,7 +78,7 @@ macro_rules! branch
macro_rules! branch_on_fn
{
($name: tt, $flag: expr, $result: literal) =>
($name: ident, $flag: expr, $result: literal) =>
{
pub fn $name(&mut self)
{
@ -84,7 +92,7 @@ macro_rules! branch_on_fn
macro_rules! set_flag_fn
{
($name: tt, $flag: expr, $result: literal) =>
($name: ident, $flag: expr, $result: literal) =>
{
pub fn $name(&mut self)
{
@ -99,7 +107,7 @@ macro_rules! set_flag_fn
macro_rules! load_fn
{
($name: tt, $register: ident) =>
($name: ident, $register: ident) =>
{
pub fn $name(&mut self)
{
@ -113,7 +121,7 @@ macro_rules! load_fn
macro_rules! store_fn
{
($name: tt, $register: ident) =>
($name: ident, $register: ident) =>
{
pub fn $name(&mut self)
{
@ -170,16 +178,26 @@ impl CPU
{
let bus = self.bus.upgrade().unwrap();
self.pc -= 1;
push!(bus.borrow_mut(), self.sp, self.pc >> 8);
push!(bus.borrow_mut(), self.sp, self.pc);
self.pc = self.absolute_addr;
}
pub fn nop(&mut self)
{
}
pub fn rts(&mut self)
{
let bus = self.bus.upgrade().unwrap();
let lo = pop(bus.borrow(), &mut self.sp) as u16;
let hi = pop(bus.borrow(), &mut self.sp) as u16;
self.pc = (hi << 8) | lo;
self.pc += 1;
}
}