From 1c99b69a12007802410cc15d0ee7ead4ec0233af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sat, 2 Jul 2022 09:35:42 +0100
Subject: [PATCH] feat: better MMu code structure
---
examples/sdl/src/main.rs | 1 +
src/gb.rs | 12 ++++++++++-
src/mmu.rs | 28 +++++++++++++++-----------
src/ppu.rs | 43 ++++++++++++++++++++--------------------
4 files changed, 49 insertions(+), 35 deletions(-)
diff --git a/examples/sdl/src/main.rs b/examples/sdl/src/main.rs
index 98732d67..011e83f9 100644
--- a/examples/sdl/src/main.rs
+++ b/examples/sdl/src/main.rs
@@ -75,6 +75,7 @@ fn main() {
let mut game_boy = GameBoy::new();
game_boy.load_boot_default();
+ game_boy.load_rom("C:/Users/joamag/Desktop/tetris.gb");
let mut counter = 0;
diff --git a/src/gb.rs b/src/gb.rs
index 3494c3f3..f1ae2ce1 100644
--- a/src/gb.rs
+++ b/src/gb.rs
@@ -1,4 +1,9 @@
-use crate::{cpu::Cpu, mmu::Mmu, ppu::{Ppu, FRAME_BUFFER_SIZE}, util::read_file};
+use crate::{
+ cpu::Cpu,
+ mmu::Mmu,
+ ppu::{Ppu, FRAME_BUFFER_SIZE},
+ util::read_file,
+};
pub struct GameBoy {
cpu: Cpu,
@@ -42,6 +47,11 @@ impl GameBoy {
&(self.ppu().frame_buffer)
}
+ pub fn load_rom(&mut self, path: &str) {
+ let data = read_file(path);
+ self.cpu.mmu().write_rom(0x0000, &data);
+ }
+
pub fn load_boot(&mut self, path: &str) {
let data = read_file(path);
self.cpu.mmu().write_boot(0x0000, &data);
diff --git a/src/mmu.rs b/src/mmu.rs
index 3dcec160..beb8b3dd 100644
--- a/src/mmu.rs
+++ b/src/mmu.rs
@@ -32,7 +32,7 @@ impl Mmu {
pub fn read(&mut self, addr: u16) -> u8 {
match addr & 0xf000 {
- // BIOS
+ // BOOT (256 B) + ROM0 (4 KB/16 KB)
0x0000 => {
// in case the boot mode is active and the
// address is withing boot memory reads from it
@@ -47,21 +47,21 @@ impl Mmu {
}
self.rom[addr as usize]
}
- // ROM0
+ // ROM0 (12 KB/16 KB)
0x1000 | 0x2000 | 0x3000 => self.rom[addr as usize],
- // ROM1 (unbanked) (16k)
+ // ROM1 (unbanked) (16 KB)
0x4000 | 0x5000 | 0x6000 | 0x7000 => self.rom[addr as usize],
- // Graphics: VRAM (8k)
+ // Graphics: VRAM (8 KB)
0x8000 | 0x9000 => {
println!("READING FROM VRAM");
self.ppu.vram[(addr & 0x1fff) as usize]
}
- // External RAM (8k)
+ // External RAM (8 KB)
0xa000 | 0xb000 => {
println!("READING FROM ERAM");
self.eram[(addr & 0x1fff) as usize]
}
- // Working RAM (8k)
+ // Working RAM (8 KB)
0xc000 | 0xd000 => self.ram[(addr & 0x1fff) as usize],
// Working RAM shadow
0xe000 => {
@@ -97,30 +97,30 @@ impl Mmu {
pub fn write(&mut self, addr: u16, value: u8) {
match addr & 0xf000 {
- // BOOT
+ // BOOT (256 B) + ROM0 (4 KB/16 KB)
0x0000 => {
println!("WRITING to BOOT")
}
- // ROM0
+ // ROM0 (12 KB/16 KB)
0x1000 | 0x2000 | 0x3000 => {
println!("WRITING TO ROM 0");
}
- // ROM1 (unbanked) (16k)
+ // ROM1 (unbanked) (16 KB)
0x4000 | 0x5000 | 0x6000 | 0x7000 => {
println!("WRITING TO ROM 1");
}
- // Graphics: VRAM (8k)
+ // Graphics: VRAM (8 KB)
0x8000 | 0x9000 => {
self.ppu.vram[(addr & 0x1fff) as usize] = value;
if addr < 0x9800 {
self.ppu.update_tile(addr, value);
}
}
- // External RAM (8k)
+ // External RAM (8 KB)
0xa000 | 0xb000 => {
println!("WRITING TO ERAM");
}
- // Working RAM (8k)
+ // Working RAM (8 KB)
0xc000 | 0xd000 => {
println!("WRITING TO RAM");
self.ram[(addr & 0x1fff) as usize] = value;
@@ -166,4 +166,8 @@ impl Mmu {
pub fn write_ram(&mut self, addr: u16, buffer: &[u8]) {
self.ram[addr as usize..addr as usize + buffer.len()].clone_from_slice(buffer);
}
+
+ pub fn write_rom(&mut self, addr: u16, buffer: &[u8]) {
+ self.rom[addr as usize..addr as usize + buffer.len()].clone_from_slice(buffer);
+ }
}
diff --git a/src/ppu.rs b/src/ppu.rs
index c43f0546..250b1d5e 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -163,7 +163,7 @@ impl Ppu {
match addr & 0x00ff {
0x0040 => {
self.switch_bg = value & 0x01 == 0x01;
- self.bg_map = value & 0x08 == 0x08;
+ self.bg_map = value & 0x08 == 0x08; // @todo o buf pode estar aqui
self.bg_tile = value & 0x10 == 0x10;
self.switch_lcd = value & 0x80 == 0x80;
}
@@ -196,12 +196,8 @@ impl Ppu {
for x in 0..8 {
mask = 1 << (7 - x);
- self.tiles[tile_index][y][x] =
- if self.vram[addr] & mask > 0 {
- 0x1
- } else {
- 0x0
- } | if self.vram[addr + 1] & mask > 0 {
+ self.tiles[tile_index][y][x] = if self.vram[addr] & mask > 0 { 0x1 } else { 0x0 }
+ | if self.vram[addr + 1] & mask > 0 {
0x2
} else {
0x0
@@ -217,6 +213,7 @@ impl Ppu {
// shifted by 3 meaning as the tiles are 8x8
let mut line_offset: usize = (self.scx >> 3) as usize;
+ // calculates both the current Y and X positions within the tiles
let y = ((self.scy + self.line) & 0x07) as usize;
let mut x = (self.scx & 0x07) as usize;
@@ -233,6 +230,23 @@ impl Ppu {
let mut frame_offset = self.line as usize * DISPLAY_WIDTH * RGB_SIZE;
for _index in 0..DISPLAY_WIDTH {
+ // obtains the current pixel data from the tile and
+ // re-maps it according to the current palette
+ let pixel = self.tiles[tile_index][y][x];
+ let color = self.palette[pixel as usize];
+
+ // set 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];
+
+ // increments the offset of the frame buffer by the
+ // size of an RGB pixel (which is 3 bytes)
+ frame_offset += RGB_SIZE;
+
+ // increments the current tile X position in drawing
+ x += 1;
+
// in case the end of tile width has been reached then
// a new tile must be retrieved for plotting
if x == 8 {
@@ -251,21 +265,6 @@ impl Ppu {
tile_index += 256;
}
}
-
- // obtains the current pixel data from the tile and
- // re-maps it according to the current palette
- let pixel = self.tiles[tile_index][y][x];
- let color = self.palette[pixel as usize];
-
- // set 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];
-
- frame_offset += RGB_SIZE;
-
- // increments the current tile X position in drawing
- x += 1;
}
}
}
--
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