From 7b85fc28204a32d0e0c54879dc209eed72d0ff9e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Thu, 7 Jul 2022 22:05:26 +0100
Subject: [PATCH] feat: initial timer strcture
---
examples/sdl/src/main.rs | 2 +-
src/cpu.rs | 7 ++++++-
src/gb.rs | 11 ++++++++---
src/lib.rs | 1 +
src/mmu.rs | 21 +++++++++++++++------
src/ppu.rs | 12 ++++++------
src/timer.rs | 27 +++++++++++++++++++++++++++
7 files changed, 64 insertions(+), 17 deletions(-)
create mode 100644 src/timer.rs
diff --git a/examples/sdl/src/main.rs b/examples/sdl/src/main.rs
index 2c916122..f72bf2aa 100644
--- a/examples/sdl/src/main.rs
+++ b/examples/sdl/src/main.rs
@@ -34,7 +34,7 @@ fn start_sdl() -> Graphics {
// creates the system window that is going to be used to
// show the emulator and sets it to the central are o screen
- let mut window = video_subsystem
+ let window = video_subsystem
.window(
TITLE,
2 as u32 * DISPLAY_WIDTH as u32, //@todo check screen scale
diff --git a/src/cpu.rs b/src/cpu.rs
index 1e29d760..34d659d3 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -4,7 +4,7 @@ use crate::{
inst::{EXTENDED, INSTRUCTIONS},
mmu::Mmu,
pad::Pad,
- ppu::Ppu,
+ ppu::Ppu, timer::Timer,
};
pub const PREFIX: u8 = 0xcb;
@@ -191,6 +191,11 @@ impl Cpu {
pub fn pad(&mut self) -> &mut Pad {
self.mmu().pad()
}
+
+ #[inline(always)]
+ pub fn timer(&mut self) -> &mut Timer {
+ self.mmu().timer()
+ }
#[inline(always)]
pub fn halted(&self) -> bool {
diff --git a/src/gb.rs b/src/gb.rs
index b58146b6..f9a12c84 100644
--- a/src/gb.rs
+++ b/src/gb.rs
@@ -4,7 +4,7 @@ use crate::{
mmu::Mmu,
pad::{Pad, PadKey},
ppu::{Ppu, Tile, FRAME_BUFFER_SIZE},
- util::read_file,
+ util::read_file, timer::Timer,
};
#[cfg(feature = "wasm")]
@@ -22,9 +22,10 @@ pub struct GameBoy {
impl GameBoy {
#[cfg_attr(feature = "wasm", wasm_bindgen(constructor))]
pub fn new() -> Self {
- let pad = Pad::new();
let ppu = Ppu::new();
- let mmu = Mmu::new(ppu, pad);
+ let pad = Pad::new();
+ let timer = Timer::new();
+ let mmu = Mmu::new(ppu, pad, timer);
let cpu = Cpu::new(mmu);
Self { cpu: cpu }
}
@@ -144,6 +145,10 @@ impl GameBoy {
self.cpu.pad()
}
+ pub fn timer(&mut self) -> &mut Timer {
+ self.cpu.timer()
+ }
+
pub fn frame_buffer(&mut self) -> &Box<[u8; FRAME_BUFFER_SIZE]> {
&(self.ppu().frame_buffer)
}
diff --git a/src/lib.rs b/src/lib.rs
index cd9b622a..11af82a5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,4 +5,5 @@ pub mod inst;
pub mod mmu;
pub mod pad;
pub mod ppu;
+pub mod timer;
pub mod util;
diff --git a/src/mmu.rs b/src/mmu.rs
index a64f6a6a..ed98c3ec 100644
--- a/src/mmu.rs
+++ b/src/mmu.rs
@@ -1,4 +1,4 @@
-use crate::{pad::Pad, ppu::Ppu};
+use crate::{pad::Pad, ppu::Ppu, timer::Timer};
pub const BIOS_SIZE: usize = 256;
pub const ROM_SIZE: usize = 32768;
@@ -6,24 +6,29 @@ pub const RAM_SIZE: usize = 8192;
pub const ERAM_SIZE: usize = 8192;
pub struct Mmu {
+ /// Register that controls the interrupts that are considered
+ /// to be enabled and should be triggered.
+ pub ie: u8,
+
+ /// Reference to the PPU (Pixel Processing Unit) that is going
+ /// to be used both for VRAM reading/writing and to forward
+ /// some of the access operations.
ppu: Ppu,
pad: Pad,
+ timer: Timer,
boot_active: bool,
boot: [u8; BIOS_SIZE],
rom: [u8; ROM_SIZE],
ram: [u8; RAM_SIZE],
eram: [u8; RAM_SIZE],
-
- /// Registers that controls the interrupts that are considered
- /// to be enabled and should be triggered.
- pub ie: u8,
}
impl Mmu {
- pub fn new(ppu: Ppu, pad: Pad) -> Self {
+ pub fn new(ppu: Ppu, pad: Pad, timer: Timer) -> Self {
Self {
ppu: ppu,
pad: pad,
+ timer: timer,
boot_active: true,
boot: [0u8; BIOS_SIZE],
rom: [0u8; ROM_SIZE],
@@ -49,6 +54,10 @@ impl Mmu {
&mut self.pad
}
+ pub fn timer(&mut self) -> &mut Timer {
+ &mut self.timer
+ }
+
pub fn boot_active(&self) -> bool {
self.boot_active
}
diff --git a/src/ppu.rs b/src/ppu.rs
index 6cb2b802..66a5c397 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -327,22 +327,22 @@ impl Ppu {
match self.mode {
PpuMode::OamRead => {
if self.mode_clock >= 80 {
- self.mode_clock = 0;
self.mode = PpuMode::VramRead;
+ self.mode_clock = self.mode_clock - 80;
}
}
PpuMode::VramRead => {
if self.mode_clock >= 172 {
self.render_line();
- self.mode_clock = 0;
self.mode = PpuMode::HBlank;
+ self.mode_clock = self.mode_clock - 172;
}
}
PpuMode::HBlank => {
if self.mode_clock >= 204 {
// increments the register that holds the
- // information about the current line in drawign
+ // information about the current line in drawing
self.ly += 1;
// in case we've reached the end of the
@@ -354,7 +354,7 @@ impl Ppu {
self.mode = PpuMode::OamRead;
}
- self.mode_clock = 0;
+ self.mode_clock = self.mode_clock - 204;
}
}
PpuMode::VBlank => {
@@ -369,7 +369,7 @@ impl Ppu {
self.ly = 0;
}
- self.mode_clock = 0;
+ self.mode_clock = self.mode_clock - 456;
}
}
}
@@ -711,7 +711,7 @@ impl Ppu {
let pixel = tile_row[if obj.xflip { 7 - x } else { x }];
let color = palette[pixel as usize];
- // set the color pixel in the frame buffer
+ // sets the color pixel in the frame buffer
self.frame_buffer[frame_offset] = color[0];
self.frame_buffer[frame_offset + 1] = color[1];
self.frame_buffer[frame_offset + 2] = color[2];
diff --git a/src/timer.rs b/src/timer.rs
new file mode 100644
index 00000000..0302f9be
--- /dev/null
+++ b/src/timer.rs
@@ -0,0 +1,27 @@
+pub struct Timer {
+ div: u8,
+ tima: u8,
+ tma: u8,
+ tac: u8,
+ ratio: u16,
+}
+
+impl Timer {
+ pub fn new() -> Self {
+ Self {
+ div: 0,
+ tima: 0,
+ tma: 0,
+ tac: 0x0,
+ ratio: 1024
+ }
+ }
+
+ pub fn read(&mut self, addr: u16) -> u8 {
+ 0x00
+ }
+
+ pub fn write(&mut self, addr: u16, value: u8) {
+ }
+}
+
--
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