From a3f12e61b46981888fcdd37c90ce685f1728c6c4 Mon Sep 17 00:00:00 2001
From: Franco Colmenarez <info@francoacg.com>
Date: Mon, 12 Dec 2022 22:04:03 -0500
Subject: [PATCH] WIP PPU structure

---
 snes-core/src/cpu/bus.rs       |  6 ++++++
 snes-core/src/emulator.rs      |  3 +++
 snes-core/src/lib.rs           |  1 +
 snes-core/src/ppu.rs           |  0
 snes-core/src/ppu/ppu.rs       |  8 ++++----
 snes-core/src/ppu/registers.rs | 13 ++++++++++++-
 6 files changed, 26 insertions(+), 5 deletions(-)
 delete mode 100644 snes-core/src/ppu.rs

diff --git a/snes-core/src/cpu/bus.rs b/snes-core/src/cpu/bus.rs
index a461b52..e517263 100644
--- a/snes-core/src/cpu/bus.rs
+++ b/snes-core/src/cpu/bus.rs
@@ -1,5 +1,8 @@
+use crate::ppu::PPU;
+
 pub struct Bus {
     wram: [u8; 0x10000],
+    pub ppu: PPU,
 }
 
 #[derive(PartialEq, Debug)]
@@ -15,6 +18,7 @@ impl Bus {
     pub fn new() -> Self {
         Self {
             wram: [0; 0x10000],
+            ppu: PPU::new(),
         }
     }
 
@@ -49,6 +53,7 @@ impl Bus {
         let section = Bus::map_address(address);
         match section {
             MemoryMap::WRAM => self.read_wram(address),
+            MemoryMap::PPU => self.ppu.registers.read(address as u16),
             _ => todo!("Implement other memory sections"),
         }
     }
@@ -57,6 +62,7 @@ impl Bus {
         let section = Bus::map_address(address);
         match section {
             MemoryMap::WRAM => self.write_wram(address, value),
+            MemoryMap::PPU => self.ppu.registers.write(address as u16, value),
             _ => todo!("Implement other memory sections"),
         }
     }
diff --git a/snes-core/src/emulator.rs b/snes-core/src/emulator.rs
index 546c77b..b90a3e3 100644
--- a/snes-core/src/emulator.rs
+++ b/snes-core/src/emulator.rs
@@ -20,5 +20,8 @@ impl Emulator {
 
     pub fn run(&mut self) {
         self.cpu.run(&mut self.bus);
+        self.bus.ppu.tick(self.cpu.cycles);
+
+        self.cpu.cycles = 0;
     }
 }
\ No newline at end of file
diff --git a/snes-core/src/lib.rs b/snes-core/src/lib.rs
index 22acfe3..80fda5f 100644
--- a/snes-core/src/lib.rs
+++ b/snes-core/src/lib.rs
@@ -1,4 +1,5 @@
 pub mod cpu;
+pub mod ppu;
 pub mod rom;
 pub mod utils;
 pub mod common;
diff --git a/snes-core/src/ppu.rs b/snes-core/src/ppu.rs
deleted file mode 100644
index e69de29..0000000
diff --git a/snes-core/src/ppu/ppu.rs b/snes-core/src/ppu/ppu.rs
index 1af242f..357180d 100644
--- a/snes-core/src/ppu/ppu.rs
+++ b/snes-core/src/ppu/ppu.rs
@@ -2,19 +2,19 @@ use super::registers::PPURegisters;
 
 pub struct PPU {
     framebuffer: Vec<u8>,
-    registers: PPURegisters,
+    pub registers: PPURegisters,
 }
 
 impl PPU {
     pub fn new() -> Self {
         Self {
             framebuffer: vec![],
-            registers: PPURegisters,
+            registers: PPURegisters::new(),
         }
     }
 
-    pub fn tick(&mut self, cycles: usize) {
-        for _ in 0..cycles {
+    pub fn tick(&mut self, cpu_cycles: usize) {
+        for _ in 0..cpu_cycles {
             self.do_cycle();
         }
     }
diff --git a/snes-core/src/ppu/registers.rs b/snes-core/src/ppu/registers.rs
index 24bfb63..9342205 100644
--- a/snes-core/src/ppu/registers.rs
+++ b/snes-core/src/ppu/registers.rs
@@ -61,10 +61,21 @@ pub const TMW: u16          = 0x212E;  // Window Area Main Screen Disable (W)
 pub const TSW: u16          = 0x212F;  // Window Area Sub Screen Disable (W)
 
 pub struct PPURegisters {
-
+    data: [u8; 256],
 }
 
 impl PPURegisters {
+    pub fn new() -> Self {
+        Self {
+            data: [0x00; 256],
+        }
+    }
 
+    pub fn read(&self, address: u16) -> u8 {
+        self.data[(address as usize) - 0x2100]
+    }
 
+    pub fn write(&mut self, address: u16, value: u8) {
+        self.data[(address as usize) - 0x2100] = value;
+    }
 }