From 965db0e0cb7fbfbd9a1d8c5391c76cb270e3c14b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sat, 6 May 2023 09:54:49 +0100
Subject: [PATCH] chore: initial support for the DMA controller This is only a
structure change and no real DMA implementation has been done.
---
src/cpu.rs | 11 +++++++++++
src/dma.rs | 17 +++++++++++++++++
src/gb.rs | 38 +++++++++++++++++++++++++++++++++++++-
src/lib.rs | 1 +
src/mmu.rs | 16 ++++++++++++++++
5 files changed, 82 insertions(+), 1 deletion(-)
create mode 100644 src/dma.rs
diff --git a/src/cpu.rs b/src/cpu.rs
index ba60309d..39bb3c01 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -3,6 +3,7 @@ use std::{cell::RefCell, rc::Rc};
use crate::{
apu::Apu,
debugln,
+ dma::Dma,
gb::GameBoyConfig,
inst::{EXTENDED, INSTRUCTIONS},
mmu::Mmu,
@@ -334,6 +335,16 @@ impl Cpu {
self.mmu_i().apu_i()
}
+ #[inline(always)]
+ pub fn dma(&mut self) -> &mut Dma {
+ self.mmu().dma()
+ }
+
+ #[inline(always)]
+ pub fn dma_i(&self) -> &Dma {
+ self.mmu_i().dma_i()
+ }
+
#[inline(always)]
pub fn pad(&mut self) -> &mut Pad {
self.mmu().pad()
diff --git a/src/dma.rs b/src/dma.rs
new file mode 100644
index 00000000..9f6d014c
--- /dev/null
+++ b/src/dma.rs
@@ -0,0 +1,17 @@
+pub struct Dma {}
+
+impl Dma {
+ pub fn new() -> Self {
+ Self {}
+ }
+
+ pub fn reset(&mut self) {}
+
+ pub fn clock(&mut self, cycles: u8) {}
+}
+
+impl Default for Dma {
+ fn default() -> Self {
+ Self::new()
+ }
+}
diff --git a/src/gb.rs b/src/gb.rs
index 9be41c40..9de814b6 100644
--- a/src/gb.rs
+++ b/src/gb.rs
@@ -10,6 +10,7 @@ use crate::{
cpu::Cpu,
data::{BootRom, CGB_BOOT, DMG_BOOT, DMG_BOOTIX, MGB_BOOTIX, SGB_BOOT},
devices::{printer::PrinterDevice, stdout::StdoutDevice},
+ dma::Dma,
gen::{COMPILATION_DATE, COMPILATION_TIME, COMPILER, COMPILER_VERSION, VERSION},
mmu::Mmu,
pad::{Pad, PadKey},
@@ -133,6 +134,9 @@ pub struct GameBoyConfig {
/// If the APU is enabled, it will be clocked.
apu_enabled: bool,
+ /// if the DMA is enabled, it will be clocked.
+ dma_enabled: bool,
+
/// If the timer is enabled, it will be clocked.
timer_enabled: bool,
@@ -186,6 +190,14 @@ impl GameBoyConfig {
self.apu_enabled = value;
}
+ pub fn dma_enabled(&self) -> bool {
+ self.dma_enabled
+ }
+
+ pub fn set_dma_enabled(&mut self, value: bool) {
+ self.dma_enabled = value;
+ }
+
pub fn timer_enabled(&self) -> bool {
self.timer_enabled
}
@@ -217,6 +229,7 @@ impl Default for GameBoyConfig {
mode: GameBoyMode::Dmg,
ppu_enabled: true,
apu_enabled: true,
+ dma_enabled: true,
timer_enabled: true,
serial_enabled: true,
clock_freq: GameBoy::CPU_FREQ,
@@ -246,6 +259,11 @@ pub struct GameBoy {
/// kept for performance reasons.
apu_enabled: bool,
+ /// If the DMA is enabled, it will be clocked.
+ /// This is a clone of the configuration value
+ /// kept for performance reasons.
+ dma_enabled: bool,
+
/// If the timer is enabled, it will be clocked.
/// This is a clone of the configuration value
/// kept for performance reasons.
@@ -314,6 +332,7 @@ impl GameBoy {
mode,
ppu_enabled: true,
apu_enabled: true,
+ dma_enabled: true,
timer_enabled: true,
serial_enabled: true,
clock_freq: GameBoy::CPU_FREQ,
@@ -321,16 +340,18 @@ impl GameBoy {
let ppu = Ppu::new(mode, gbc.clone());
let apu = Apu::default();
+ let dma = Dma::default();
let pad = Pad::default();
let timer = Timer::default();
let serial = Serial::default();
- let mmu = Mmu::new(ppu, apu, pad, timer, serial, mode, gbc.clone());
+ let mmu = Mmu::new(ppu, apu, dma, pad, timer, serial, mode, gbc.clone());
let cpu = Cpu::new(mmu, gbc.clone());
Self {
mode,
ppu_enabled: true,
apu_enabled: true,
+ dma_enabled: true,
timer_enabled: true,
serial_enabled: true,
clock_freq: GameBoy::CPU_FREQ,
@@ -356,6 +377,9 @@ impl GameBoy {
if self.apu_enabled {
self.apu_clock(cycles);
}
+ if self.dma_enabled {
+ self.dma_clock(cycles);
+ }
if self.timer_enabled {
self.timer_clock(cycles);
}
@@ -385,6 +409,10 @@ impl GameBoy {
self.apu().clock(cycles)
}
+ pub fn dma_clock(&mut self, cycles: u8) {
+ self.dma().clock(cycles)
+ }
+
pub fn timer_clock(&mut self, cycles: u8) {
self.timer().clock(cycles)
}
@@ -735,6 +763,14 @@ impl GameBoy {
self.cpu.apu_i()
}
+ pub fn dma(&mut self) -> &mut Dma {
+ self.cpu.dma()
+ }
+
+ pub fn dma_i(&self) -> &Dma {
+ self.cpu.dma_i()
+ }
+
pub fn pad(&mut self) -> &mut Pad {
self.cpu.pad()
}
diff --git a/src/lib.rs b/src/lib.rs
index 80f4f5b8..d25f5ac6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,7 @@ pub mod apu;
pub mod cpu;
pub mod data;
pub mod devices;
+pub mod dma;
pub mod gb;
pub mod gen;
pub mod inst;
diff --git a/src/mmu.rs b/src/mmu.rs
index c6a0eea1..6b7ebe86 100644
--- a/src/mmu.rs
+++ b/src/mmu.rs
@@ -3,6 +3,7 @@ use std::{cell::RefCell, rc::Rc};
use crate::{
apu::Apu,
debugln,
+ dma::Dma,
gb::{GameBoyConfig, GameBoyMode, GameBoySpeed},
pad::Pad,
ppu::Ppu,
@@ -44,6 +45,11 @@ pub struct Mmu {
/// some of the access operations.
apu: Apu,
+ /// Reference to the DMA (Direct Memory Access) controller that is going
+ /// to be used for quick and CPU offloaded memory transfers.
+ /// There are multiple execution modes for the DMA.
+ dma: Dma,
+
/// Reference to the Gamepad structure that is going to control
/// the I/O access to this device.
pad: Pad,
@@ -95,6 +101,7 @@ impl Mmu {
pub fn new(
ppu: Ppu,
apu: Apu,
+ dma: Dma,
pad: Pad,
timer: Timer,
serial: Serial,
@@ -104,6 +111,7 @@ impl Mmu {
Self {
ppu,
apu,
+ dma,
pad,
timer,
serial,
@@ -161,6 +169,14 @@ impl Mmu {
&self.apu
}
+ pub fn dma(&mut self) -> &mut Dma {
+ &mut self.dma
+ }
+
+ pub fn dma_i(&self) -> &Dma {
+ &self.dma
+ }
+
pub fn pad(&mut self) -> &mut Pad {
&mut self.pad
}
--
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