[core] Refactor DMG compat palettes and add licensee code tests

Cargo.toml

@@ -53,7 +53,7 @@ egui = "0.28.1"
 enum_dispatch = "0.3.13"
 env_logger = "0.11.3"
 gb-core = { path = "./core/gb-core" }
-image = { version = "0.25.1", default-features = false }
+image = { version = "0.25.2", default-features = false }
 itertools = "0.13.0"
 libretro-rs = "0.1.3"
 log = "0.4.22"
@@ -63,6 +63,6 @@ rfd = "0.14.1"
 sdl2 = "0.37.0"
 serde = { version = "1.0.204", features = ["derive"] }
 serde_json = "1.0.120"
-thiserror = "1.0.62"
+thiserror = "1.0.63"
 wasm-bindgen = "0.2.92"
 web-sys = "0.3.69"

DEVELOPMENT.md

@@ -25,9 +25,27 @@ cargo +nightly fmt --all && cargo clippy --all-targets
 https://github.com/flamegraph-rs/flamegraph
 
 ```sh
+# cargo
+cargo install flamegraph
+
 # Arch
 sudo pacman -S cargo-flamegraph
 
 cargo flamegraph --dev -- roms/rom.gb
 CARGO_PROFILE_RELEASE_DEBUG=true cargo flamegraph -- roms/rom.gb
 ```
+
+## Upgrading packages
+
+```sh
+# cargo
+cargo install cargo-edit
+
+# brew
+brew install cargo-edit
+
+# Arch
+sudo pacman -S cargo-edit
+
+cargo upgrade -i && cargo update
+```

core/gb-core/src/cartridge.rs

@@ -61,8 +61,11 @@ impl Cartridge {
         log::info!("RAM banks: {ram_banks}");
         log::info!("CGB flag: {cgb_flag}");
         log::info!("SGB flag: {sgb_flag:?}");
-        log::info!("Old licensee code: {:#04X}", licensee_code.old());
-        log::info!("New licensee code: {}", licensee_code.new_as_string());
+        log::info!("Old licensee code: {:#04X}", licensee_code.old_code());
+        log::info!(
+            "New licensee code: {}",
+            licensee_code.new_code().unwrap_or("--")
+        );
 
         Ok(Self {
             rom,

core/gb-core/src/cartridge/compatibility_palettes.rs

@@ -2,12 +2,11 @@
 // 1. https://gbdev.io/pandocs/Power_Up_Sequence.html#compatibility-palettes
 // 2. https://github.com/LIJI32/SameBoy/blob/master/BootROMs/cgb_boot.asm
 
-use self::{
-    palette_combinations::PALETTE_COMBINATIONS,
-    palette_id_lookup_table::PALETTE_ID_LOOKUP_TABLE,
-    title_checksum_lookup_table::TITLE_CHECKSUM_LOOKUP_TABLE,
-};
-use super::{licensee_code::LicenseeCode, title::Title};
+use palette_id::get_palette_id;
+use palette_id_index::get_palette_id_index;
+use palettes::get_palettes_from_id;
+
+use crate::cartridge::{licensee_code::LicenseeCode, title::Title};
 
 pub struct CompatibilityPalettes {
     pub bg0: [u16; 4],
@@ -16,49 +15,24 @@ pub struct CompatibilityPalettes {
 }
 
 impl CompatibilityPalettes {
-    pub const DEFAULT: Self = PALETTE_COMBINATIONS[0].into_palettes();
+    pub const DEFAULT: Self = get_palettes_from_id(0);
 
     pub fn from_header_info(licensee_code: &LicenseeCode, title: &Title) -> Self {
-        match licensee_code.old() {
-            0x33 => {
-                if !(licensee_code.new_as_string() == "01"
-                    || u16::from_le_bytes(*licensee_code.new_as_bytes()) == 0x01)
-                {
-                    return Self::DEFAULT;
-                }
-            }
-
-            0x01 => (),
-
-            _ => return Self::DEFAULT,
-        };
-
-        let title_checksum = title.checksum();
+        if !licensee_code.is_nintendo() {
+            return Self::DEFAULT;
+        }
 
-        let Some(checksum_index) = TITLE_CHECKSUM_LOOKUP_TABLE
-            .into_iter()
-            .position(|x| x == title_checksum)
-        else {
+        let Some(palette_id_index) = get_palette_id_index(title) else {
             return Self::DEFAULT;
         };
 
-        let palette_id = if checksum_index <= 64 {
-            PALETTE_ID_LOOKUP_TABLE[checksum_index]
-        } else {
-            let fourth_byte = title.as_bytes()[3];
-            let row = title_row_lookup_table::find_row(checksum_index - 65, fourth_byte);
-            let index = checksum_index + (14 * row);
-
-            PALETTE_ID_LOOKUP_TABLE[index]
-        };
+        let palette_id = get_palette_id(palette_id_index);
 
-        PALETTE_COMBINATIONS[palette_id].into_palettes()
+        get_palettes_from_id(palette_id)
     }
 }
 
-mod palette_combinations;
-mod palette_id_lookup_table;
-mod palette_lookup_table;
-mod palette_lookup_type;
-mod title_checksum_lookup_table;
-mod title_row_lookup_table;
+mod palette;
+mod palette_id;
+mod palette_id_index;
+mod palettes;

core/gb-core/src/cartridge/compatibility_palettes/palette_lookup_table.rs → core/gb-core/src/cartridge/compatibility_palettes/palette.rs

@@ -2,7 +2,10 @@
 // 1. https://gbdev.io/pandocs/Power_Up_Sequence.html#compatibility-palettes
 // 2. https://github.com/LIJI32/SameBoy/blob/master/BootROMs/cgb_boot.asm
 
-pub const fn from_index_start(id: usize) -> [u16; 4] {
+/// **Fourth step**
+///
+/// Returns the palette from the id obtained in the previous step.
+pub const fn palette_from_id(id: usize) -> [u16; 4] {
     [
         PALETTE_LOOKUP_TABLE[id],
         PALETTE_LOOKUP_TABLE[id + 1],
@@ -11,7 +14,7 @@ pub const fn from_index_start(id: usize) -> [u16; 4] {
     ]
 }
 
-pub const PALETTE_LOOKUP_TABLE: [u16; 120] = [
+const PALETTE_LOOKUP_TABLE: [u16; 120] = [
     0x7FFF, 0x32BF, 0x00D0, 0x0000, // 0
     0x639F, 0x4279, 0x15B0, 0x04CB, // 1
     0x7FFF, 0x6E31, 0x454A, 0x0000, // 2

core/gb-core/src/cartridge/compatibility_palettes/palette_id_lookup_table.rs → core/gb-core/src/cartridge/compatibility_palettes/palette_id.rs

@@ -2,7 +2,15 @@
 // 1. https://gbdev.io/pandocs/Power_Up_Sequence.html#compatibility-palettes
 // 2. https://github.com/LIJI32/SameBoy/blob/master/BootROMs/cgb_boot.asm
 
-pub const PALETTE_ID_LOOKUP_TABLE: [usize; 94] = [
+/// **Second step**
+///
+/// Used to obtain the palette id given its index from the lookup table.
+pub const fn get_palette_id(index: usize) -> usize {
+    PALETTE_ID[index]
+}
+
+/// Indexeded by the index of the title checksum.
+const PALETTE_ID: [usize; 94] = [
     0,  // Default Palette
     4,  // ALLEY WAY
     5,  // YAKUMAN

core/gb-core/src/cartridge/compatibility_palettes/palette_id_index.rs

@@ -0,0 +1,63 @@
+// Taken from
+// 1. https://gbdev.io/pandocs/Power_Up_Sequence.html#compatibility-palettes
+// 2. https://github.com/LIJI32/SameBoy/blob/master/BootROMs/cgb_boot.asm
+
+use crate::cartridge::title::Title;
+
+/// **First step**
+///
+/// Used to obtain the index of the palette id.
+pub fn get_palette_id_index(title: &Title) -> Option<usize> {
+    let title_checksum = title.checksum();
+
+    let checksum_index = TITLE_CHECKSUM
+        .into_iter()
+        .position(|x| x == title_checksum)?;
+
+    if checksum_index <= 64 {
+        Some(checksum_index)
+    } else {
+        let fourth_byte = title.as_bytes()[3];
+        let row = find_title_row(checksum_index - 65, fourth_byte);
+        let index = checksum_index + (14 * row);
+
+        Some(index)
+    }
+}
+
+/// The index will be the index that corresponds to the value of the title checksum in this table.
+const TITLE_CHECKSUM: [u8; 79] = [
+    0x00, 0x88, 0x16, 0x36, 0xD1, 0xDB, 0xF2, 0x3C, 0x8C, 0x92, 0x3D, 0x5C, 0x58, 0xC9, 0x3E, 0x70,
+    0x1D, 0x59, 0x69, 0x19, 0x35, 0xA8, 0x14, 0xAA, 0x75, 0x95, 0x99, 0x34, 0x6F, 0x15, 0xFF, 0x97,
+    0x4B, 0x90, 0x17, 0x10, 0x39, 0xF7, 0xF6, 0xA2, 0x49, 0x4E, 0x43, 0x68, 0xE0, 0x8B, 0xF0, 0xCE,
+    0x0C, 0x29, 0xE8, 0xB7, 0x86, 0x9A, 0x52, 0x01, 0x9D, 0x71, 0x9C, 0xBD, 0x5D, 0x6D, 0x67, 0x3F,
+    0x6B, // <-- 64
+    // Ambiguous. Refer to the fourth byte in the title if the index is >64.
+    0xB3, 0x46, 0x28, 0xA5, 0xC6, 0xD3, 0x27, 0x61, 0x18, 0x66, 0x6A, 0xBF, 0x0D, 0xF4,
+];
+
+/// If the index of the checksum is <= 64, don't use this.
+/// If > 64, this will return the index of the palette id lookup table.
+fn find_title_row(column: usize, fourth_byte: u8) -> usize {
+    const TITLE_ROW_LOOKUP_TABLE: [&str; 3] = ["BEFAARBEKEK R-", "URAR INAILICE ", "R"];
+
+    if let Some(ch) = TITLE_ROW_LOOKUP_TABLE[0].as_bytes().get(column) {
+        if *ch == fourth_byte {
+            return 0;
+        }
+    }
+
+    if let Some(ch) = TITLE_ROW_LOOKUP_TABLE[1].as_bytes().get(column) {
+        if *ch == fourth_byte {
+            return 1;
+        }
+    }
+
+    if let Some(ch) = TITLE_ROW_LOOKUP_TABLE[2].as_bytes().get(column) {
+        if *ch == fourth_byte {
+            return 2;
+        }
+    }
+
+    0
+}

core/gb-core/src/cartridge/compatibility_palettes/palette_combinations.rs → core/gb-core/src/cartridge/compatibility_palettes/palettes.rs

@@ -2,10 +2,36 @@
 // 1. https://gbdev.io/pandocs/Power_Up_Sequence.html#compatibility-palettes
 // 2. https://github.com/LIJI32/SameBoy/blob/master/BootROMs/cgb_boot.asm
 
-use super::palette_lookup_type::PaletteLookupKind::{self, Normal, Raw};
+use super::palette::palette_from_id;
+use crate::cartridge::compatibility_palettes::CompatibilityPalettes;
+
+/// **Third step**
+///
+/// From the palette id, get each palette for BG0, OBJ1 and OBJ2.
+pub const fn get_palettes_from_id(id: usize) -> CompatibilityPalettes {
+    let (obj0, obj1, bg0) = match PALETTE_COMBINATIONS[id] {
+        PaletteLookupKind::Normal(obj0, obj1, bg0) => (obj0 * 4, obj1 * 4, bg0 * 4),
+        PaletteLookupKind::Raw(obj0, obj1, bg0) => (obj0, obj1, bg0),
+    };
+
+    CompatibilityPalettes {
+        bg0: palette_from_id(bg0),
+        obj0: palette_from_id(obj0),
+        obj1: palette_from_id(obj1),
+    }
+}
+
+/// (OBJ0, OBJ1, BG0)
+#[derive(Debug, Clone, Copy)]
+enum PaletteLookupKind {
+    Normal(usize, usize, usize),
+    Raw(usize, usize, usize),
+}
+
+use PaletteLookupKind::{Normal, Raw};
 
 #[allow(clippy::erasing_op)]
-pub const PALETTE_COMBINATIONS: [PaletteLookupKind; 51] = [
+const PALETTE_COMBINATIONS: [PaletteLookupKind; 51] = [
     Normal(4, 4, 29),
     Normal(18, 18, 18),
     Normal(20, 20, 20),

core/gb-core/src/cartridge/header.rs

@@ -2,8 +2,8 @@ use super::error::Error;
 
 /// Not the actual start, we're starting at 0 for convenience, as 0..0x100 is the bootrom area.
 /// The actual start is at 0x100.
-pub const HEADER_START: usize = 0;
-pub const HEADER_END: usize = 0x014F;
+const HEADER_START: usize = 0;
+const HEADER_END: usize = 0x014F;
 
 pub const HEADER_SIZE: usize = HEADER_START + HEADER_END + 1;