From 72340fc8477baaaf5ea0e059e7a8c611ffd767c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Tue, 28 Jun 2022 21:11:39 +0100
Subject: [PATCH] feat: better stack operations
---
examples/sdl/src/main.rs | 5 +++--
src/cpu.rs | 30 +++++++++++++++++++++++++-----
2 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/examples/sdl/src/main.rs b/examples/sdl/src/main.rs
index 77da12f8..bc62660b 100644
--- a/examples/sdl/src/main.rs
+++ b/examples/sdl/src/main.rs
@@ -4,9 +4,10 @@ fn main() {
let mut game_boy = GameBoy::new();
game_boy.load_boot_default();
- for _ in 0..40000 {
+ for i in 0..24612 {
game_boy.clock();
- if game_boy.cpu().pc() >= 0x0032 {
+ if game_boy.cpu().pc() >= 0x3032 {
+ println!("{}", i);
break;
}
}
diff --git a/src/cpu.rs b/src/cpu.rs
index ab674168..d663cdf8 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -87,7 +87,7 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 256] = [
(nop, 4, "NOP"),
(nop, 4, "NOP"),
(nop, 4, "NOP"),
- (nop, 4, "NOP"),
+ (ld_c_a, 4, "LD C, A"),
// 0x5 opcodes
(nop, 4, "NOP"),
(nop, 4, "NOP"),
@@ -213,7 +213,7 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 256] = [
(nop, 4, "NOP"),
(nop, 4, "NOP"),
(nop, 4, "NOP"),
- (nop, 4, "NOP"),
+ (push_bc, 16, "PUSH BC"),
(nop, 4, "NOP"),
(nop, 4, "NOP"),
(nop, 4, "NOP"),
@@ -613,6 +613,18 @@ impl Cpu {
word
}
+ #[inline(always)]
+ fn push_byte(&mut self, byte: u8){
+ self.sp -= 1;
+ self.mmu.write(self.sp, byte);
+ }
+
+ #[inline(always)]
+ fn push_word(&mut self, word: u16) {
+ self.push_byte((word >> 8) as u8);
+ self.push_byte(word as u8);
+ }
+
#[inline(always)]
fn get_zero(&self) -> bool {
self.zero
@@ -771,6 +783,10 @@ fn ld_a_u8(cpu: &mut Cpu) {
cpu.a = byte;
}
+fn ld_c_a(cpu: &mut Cpu) {
+ cpu.c = cpu.a;
+}
+
fn xor_a_a(cpu: &mut Cpu) {
cpu.a ^= cpu.a;
@@ -780,10 +796,14 @@ fn xor_a_a(cpu: &mut Cpu) {
cpu.set_carry(false);
}
+fn push_bc(cpu: &mut Cpu) {
+ cpu.push_word(cpu.bc());
+}
+
fn call_u16(cpu: &mut Cpu) {
- // @todo push stack and set the current PC
- // to be able to jump
- cpu.sp += 1;
+ let word = cpu.read_u16();
+ cpu.push_word(cpu.pc);
+ cpu.pc = word;
}
fn ld_mff00u8_a(cpu: &mut Cpu) {
--
GitLab