From 669e7565c9048e0504a4d301e0a3c514abb7205e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Fri, 1 Jul 2022 18:44:58 +0100
Subject: [PATCH] feat: better structure of instruction execution
---
examples/sdl/src/main.rs | 2 +-
src/cpu.rs | 35 +++++++++++++++++++++++++++--------
src/mmu.rs | 2 +-
3 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/examples/sdl/src/main.rs b/examples/sdl/src/main.rs
index 4a56914a..98732d67 100644
--- a/examples/sdl/src/main.rs
+++ b/examples/sdl/src/main.rs
@@ -79,7 +79,7 @@ fn main() {
let mut counter = 0;
'main: loop {
- if counter >= 7000000 {
+ if counter >= 700000000 {
break;
}
diff --git a/src/cpu.rs b/src/cpu.rs
index 96f5e9f9..4ad39386 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -26,7 +26,7 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 256] = [
(noimpl, 4, "! UNIMP !"),
(inc_de, 8, "INC DE"),
(noimpl, 4, "! UNIMP !"),
- (noimpl, 4, "! UNIMP !"),
+ (dec_d, 4, "DEC D"),
(noimpl, 4, "! UNIMP !"),
(rla, 4, "RLA"),
(jr_i8, 12, "JR i8"),
@@ -157,7 +157,7 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 256] = [
(noimpl, 4, "! UNIMP !"),
(noimpl, 4, "! UNIMP !"),
// 0x9 opcodes
- (noimpl, 4, "! UNIMP !"),
+ (sub_a_b, 4, "SUB A, B"),
(noimpl, 4, "! UNIMP !"),
(noimpl, 4, "! UNIMP !"),
(noimpl, 4, "! UNIMP !"),
@@ -527,10 +527,16 @@ impl Cpu {
let (instruction_fn, instruction_time, instruction_str) = instruction;
- println!(
- "{}\t(0x{:02x})\t${:04x} {}",
- instruction_str, opcode, pc, is_prefix
- );
+ if *instruction_str == "! UNIMP !" {
+ println!(
+ "{}\t(0x{:02x})\t${:04x} {}",
+ instruction_str, opcode, pc, is_prefix
+ );
+ }
+
+ if pc == 0x0080 {
+ println!("GOING TO PLAY BOOT SOUND");
+ }
instruction_fn(self);
self.ticks = self.ticks.wrapping_add(*instruction_time as u32);
@@ -802,6 +808,16 @@ fn inc_de(cpu: &mut Cpu) {
cpu.set_de(cpu.de().wrapping_add(1));
}
+fn dec_d(cpu: &mut Cpu) {
+ let value = cpu.d.wrapping_sub(1);
+
+ cpu.set_sub(true);
+ cpu.set_zero(value == 0);
+ cpu.set_half_carry((value & 0xf) == 0xf);
+
+ cpu.d = value;
+}
+
fn rla(cpu: &mut Cpu) {
let carry = cpu.get_carry();
@@ -942,6 +958,10 @@ fn ld_a_h(cpu: &mut Cpu) {
cpu.a = cpu.h;
}
+fn sub_a_b(cpu: &mut Cpu) {
+ cpu.a = sub_set_flags(cpu, cpu.a, cpu.b);
+}
+
fn xor_a_a(cpu: &mut Cpu) {
cpu.a ^= cpu.a;
@@ -1041,12 +1061,11 @@ fn bit_h(cpu: &mut Cpu, bit: u8) {
}
fn sub_set_flags(cpu: &mut Cpu, x: u8, y: u8) -> u8 {
- // Check for borrow using 32bit arithmetics
+ // checks for borrow using 32bit arithmetics
let x = x as u32;
let y = y as u32;
let value = x.wrapping_sub(y);
-
let value_b = value as u8;
cpu.set_sub(true);
diff --git a/src/mmu.rs b/src/mmu.rs
index 8c79e05e..3dcec160 100644
--- a/src/mmu.rs
+++ b/src/mmu.rs
@@ -148,7 +148,7 @@ impl Mmu {
self.ppu.write(addr, value);
}
_ => {
- println!("Writing to Unknown IO control 0x{:04x}", addr);
+ println!("Writing to unknown IO control 0x{:04x}", addr);
}
}
}
--
GitLab