wip: refactor rom module

crates/mes-core/src/bus/ppu.rs

@@ -1,7 +1,7 @@
 use crate::{
     bus::Bus,
-    cartridge::Mirroring,
     mappers::{Mapper, MapperChip},
+    rom::Mirroring,
     utils::{Clock, Reset},
 };
 

crates/mes-core/src/features/json.rs

@@ -1,4 +1,4 @@
-use crate::{cartridge::Header, error::Error};
+use crate::{error::Error, rom::ines::Header};
 
 pub fn serialize_rom_header(bytes: &[u8]) -> Result<String, Error> {
     let header = Header::try_from_bytes(bytes)?;

crates/mes-core/src/lib.rs

@@ -1,11 +1,11 @@
 pub mod apu;
 pub mod bus;
-pub mod cartridge;
 pub mod controller;
 pub mod cpu;
 pub mod error;
 pub mod mappers;
 pub mod ppu;
+pub mod rom;
 pub mod utils;
 
 mod features;

crates/mes-core/src/mappers/mapper_000.rs

@@ -2,7 +2,10 @@
 
 use super::Mapper;
 use crate::{
-    cartridge::{Cartridge, ChrPage, Mirroring, PrgPage},
+    rom::{
+        cartridge::{Cartridge, ChrPage, PrgPage},
+        Mirroring,
+    },
     utils::Reset,
 };
 

crates/mes-core/src/mappers/mapper_001.rs

@@ -2,7 +2,10 @@
 
 use super::Mapper;
 use crate::{
-    cartridge::{Cartridge, ChrPage, Mirroring, PrgPage},
+    rom::{
+        cartridge::{Cartridge, ChrPage, PrgPage},
+        Mirroring,
+    },
     utils::{BitFlag, Reset},
 };
 
@@ -102,7 +105,7 @@ impl Mapper for SxRom {
         }
     }
 
-    fn get_mirroring(&self) -> crate::cartridge::Mirroring {
+    fn get_mirroring(&self) -> crate::rom::Mirroring {
         match self.control & 0b11 {
             2 => Mirroring::Vertical,
             3 => Mirroring::Horizontal,

crates/mes-core/src/mappers/mapper_002.rs

@@ -2,7 +2,10 @@
 
 use super::Mapper;
 use crate::{
-    cartridge::{Cartridge, ChrPage, Mirroring, PrgPage},
+    rom::{
+        cartridge::{Cartridge, ChrPage, PrgPage},
+        Mirroring,
+    },
     utils::Reset,
 };
 

crates/mes-core/src/mappers/mapper_003.rs

@@ -2,7 +2,10 @@
 
 use super::Mapper;
 use crate::{
-    cartridge::{Cartridge, ChrPage, Mirroring, PrgPage},
+    rom::{
+        cartridge::{Cartridge, ChrPage, PrgPage},
+        Mirroring,
+    },
     utils::Reset,
 };
 

crates/mes-core/src/mappers/mod.rs

@@ -6,8 +6,8 @@ mod mapper_003;
 use self::{mapper_000::NRom, mapper_001::SxRom, mapper_002::UxRom, mapper_003::CnRom};
 
 use crate::{
-    cartridge::{Cartridge, Mirroring},
     error::Error,
+    rom::{cartridge::Cartridge, Mirroring},
     utils::{MemoryObserver, Reset},
 };
 
@@ -26,7 +26,7 @@ pub struct MapperBuilder {
 impl MapperBuilder {
     pub fn new(cartridge: &[u8]) -> Result<Self, Error> {
         Ok(Self {
-            cartridge: Cartridge::try_from_bytes(cartridge)?,
+            cartridge: Cartridge::try_from_ines(cartridge)?,
         })
     }
 
@@ -58,7 +58,7 @@ impl MapperChip {
     }
 
     pub fn try_from_bytes(bytes: &[u8]) -> Result<Self, Error> {
-        Cartridge::try_from_bytes(bytes).and_then(MapperChip::try_from)
+        Cartridge::try_from_ines(bytes).and_then(MapperChip::try_from)
     }
 }
 

crates/mes-core/src/cartridge/mod.rs → crates/mes-core/src/rom/cartridge.rs

@@ -1,81 +1,14 @@
-// https://www.nesdev.org/wiki/INES
+use crate::{error::Error, utils::MemoryObserver};
 
-use crate::{
-    error::Error,
-    utils::{BitFlag, MemoryObserver},
+use super::{
+    ines::{Header, INES_HEADER_SIZE, TRAINER_SIZE},
+    Mirroring,
 };
 
-#[cfg(feature = "json")]
-use serde::Serialize;
-
-const INES_ASCII: [u8; 4] = [0x4E, 0x45, 0x53, 0x1A];
-const INES_HEADER_SIZE: usize = 16;
-const TRAINER_SIZE: usize = 512;
-const PRG_ROM_PAGE_SIZE: usize = 16384;
-const PRG_RAM_SIZE: usize = 8192;
-const CHR_ROM_PAGE_SIZE: usize = 8192;
-const CHR_RAM_PAGE_SIZE: usize = 8192;
-
-pub fn is_ines_file(bytes: &[u8]) -> bool {
-    bytes[0..4] == INES_ASCII
-}
-
-#[derive(Debug, Clone, Copy, PartialEq)]
-#[cfg_attr(feature = "json", derive(Serialize))]
-pub enum Mirroring {
-    Vertical,
-    Horizontal,
-    OneScreen,
-    FourScreen,
-}
-
-#[derive(Debug)]
-#[cfg_attr(feature = "json", derive(Serialize))]
-pub struct Header {
-    pub prg_rom_pages: u8,
-    pub chr_rom_pages: u8,
-    pub prg_ram_pages: u8,
-    pub mirroring: Mirroring,
-    pub battery: bool,
-    pub trainer: bool,
-    pub mapper: u8,
-}
-
-impl Header {
-    pub fn try_from_bytes(bytes: &[u8]) -> Result<Self, Error> {
-        if !is_ines_file(bytes) {
-            return Err(Error::UnsupportedFileFormat);
-        }
-
-        let prg_rom_pages = *bytes.get(4).ok_or(Error::eof("PRG ROM pages", 1))?;
-        let chr_rom_pages = *bytes.get(5).ok_or(Error::eof("CHR ROM pages", 1))?;
-        let flags_6 = bytes.get(6).ok_or(Error::eof("Flags 6", 1))?;
-        let flags_7 = bytes.get(7).ok_or(Error::eof("Flags 7", 1))?;
-        let prg_ram_pages = *bytes.get(8).ok_or(Error::eof("PRG RAM pages", 1))?;
-
-        let battery = flags_6.contains(1);
-        let trainer = flags_6.contains(2);
-        let mapper = (flags_7 & 0xF0) | (flags_6 >> 4);
-        let is_vertical_mirroring = flags_6.contains(0);
-        let is_four_screen = flags_6.contains(3);
-
-        let mirroring = match (is_four_screen, is_vertical_mirroring) {
-            (true, _) => Mirroring::FourScreen,
-            (false, true) => Mirroring::Vertical,
-            (false, false) => Mirroring::Horizontal,
-        };
-
-        Ok(Self {
-            prg_rom_pages,
-            prg_ram_pages,
-            chr_rom_pages,
-            mirroring,
-            battery,
-            trainer,
-            mapper,
-        })
-    }
-}
+pub const PRG_ROM_PAGE_SIZE: usize = 16384;
+pub const PRG_RAM_SIZE: usize = 8192;
+pub const CHR_ROM_PAGE_SIZE: usize = 8192;
+pub const CHR_RAM_PAGE_SIZE: usize = 8192;
 
 pub enum ChrPage {
     Index4(u8),
@@ -104,7 +37,7 @@ impl std::fmt::Debug for Cartridge {
 }
 
 impl Cartridge {
-    pub fn try_from_bytes(bytes: &[u8]) -> Result<Self, Error> {
+    pub fn try_from_ines(bytes: &[u8]) -> Result<Self, Error> {
         let header = Header::try_from_bytes(bytes)?;
 
         let prg_rom_size = header.prg_rom_pages as usize * PRG_ROM_PAGE_SIZE;
@@ -113,8 +46,7 @@ impl Cartridge {
         let chr_rom_start = prg_rom_start + prg_rom_size;
         let prg_rom = bytes[prg_rom_start..prg_rom_start + prg_rom_size].to_vec();
         let chr_rom = bytes[chr_rom_start..chr_rom_start + chr_rom_size].to_vec();
-        let prg_ram_size = PRG_RAM_SIZE;
-        let prg_ram = vec![0_u8; prg_ram_size];
+        let prg_ram = vec![0_u8; PRG_RAM_SIZE];
         let chr_ram_size = (header.chr_rom_pages == 0) as usize * CHR_RAM_PAGE_SIZE;
         let chr_ram = vec![0_u8; chr_ram_size];
 
@@ -207,7 +139,7 @@ mod tests {
 
     #[test]
     fn test_load_rom() {
-        let rom = Cartridge::try_from_bytes(&NESTEST_ROM);
+        let rom = Cartridge::try_from_ines(&NESTEST_ROM);
 
         assert!(rom.is_ok());
     }

crates/mes-core/src/rom/ines.rs

@@ -0,0 +1,62 @@
+#[cfg(feature = "json")]
+use serde::Serialize;
+
+use crate::{error::Error, utils::BitFlag};
+
+use super::Mirroring;
+
+pub const INES_ASCII: [u8; 4] = [0x4E, 0x45, 0x53, 0x1A];
+pub const INES_HEADER_SIZE: usize = 16;
+pub const TRAINER_SIZE: usize = 512;
+
+pub fn is_ines_file(bytes: &[u8]) -> bool {
+    bytes[0..4] == INES_ASCII
+}
+
+#[derive(Debug)]
+#[cfg_attr(feature = "json", derive(Serialize))]
+pub struct Header {
+    pub prg_rom_pages: u8,
+    pub chr_rom_pages: u8,
+    pub prg_ram_pages: u8,
+    pub mirroring: Mirroring,
+    pub battery: bool,
+    pub trainer: bool,
+    pub mapper: u8,
+}
+
+impl Header {
+    pub fn try_from_bytes(bytes: &[u8]) -> Result<Self, Error> {
+        if !is_ines_file(bytes) {
+            return Err(Error::UnsupportedFileFormat);
+        }
+
+        let prg_rom_pages = *bytes.get(4).ok_or(Error::eof("PRG ROM pages", 1))?;
+        let chr_rom_pages = *bytes.get(5).ok_or(Error::eof("CHR ROM pages", 1))?;
+        let flags_6 = bytes.get(6).ok_or(Error::eof("Flags 6", 1))?;
+        let flags_7 = bytes.get(7).ok_or(Error::eof("Flags 7", 1))?;
+        let prg_ram_pages = *bytes.get(8).ok_or(Error::eof("PRG RAM pages", 1))?;
+
+        let battery = flags_6.contains(1);
+        let trainer = flags_6.contains(2);
+        let mapper = (flags_7 & 0xF0) | (flags_6 >> 4);
+        let is_vertical_mirroring = flags_6.contains(0);
+        let is_four_screen = flags_6.contains(3);
+
+        let mirroring = match (is_four_screen, is_vertical_mirroring) {
+            (true, _) => Mirroring::FourScreen,
+            (false, true) => Mirroring::Vertical,
+            (false, false) => Mirroring::Horizontal,
+        };
+
+        Ok(Self {
+            prg_rom_pages,
+            prg_ram_pages,
+            chr_rom_pages,
+            mirroring,
+            battery,
+            trainer,
+            mapper,
+        })
+    }
+}

crates/mes-core/src/rom/mod.rs

@@ -0,0 +1,17 @@
+// https://www.nesdev.org/wiki/INES
+
+pub mod cartridge;
+pub mod fds;
+pub mod ines;
+
+#[cfg(feature = "json")]
+use serde::Serialize;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+#[cfg_attr(feature = "json", derive(Serialize))]
+pub enum Mirroring {
+    Vertical,
+    Horizontal,
+    OneScreen,
+    FourScreen,
+}