Rename repo to Zig GBA to build more of a SDK

* Add GBA static library
* Create examples folder and move "Hello World" to examples/first
* Add GBA/builder.zig helper for simplifying setup of building GBA ROM

.vscode/tasks.json

@@ -17,6 +17,7 @@
             "label": "Format current file",
             "type": "shell",
             "command": "zig fmt ${file}",
+            "problemMatcher": []
         }
     ]
 }

GBA/builder.zig

@@ -0,0 +1,72 @@
+const Builder = @import("std").build.Builder;
+const LibExeObjStep = @import("std").build.LibExeObjStep;
+const builtin = @import("std").builtin;
+const fmt = @import("std").fmt;
+const FixedBufferAllocator = @import("std").heap.FixedBufferAllocator;
+const std = @import("std");
+const fs = @import("std").fs;
+
+const GBALinkerScript = "GBA/gba.ld";
+
+fn gbaThumbTarget() std.Target {
+    return std.Target{
+        .Cross = std.Target.Cross{
+            .arch = std.Target.Arch{ .thumb = std.Target.Arch.Arm32.v4t },
+            .os = .freestanding,
+            .abi = .none,
+        },
+    };
+}
+
+pub fn addGBAStaticLibrary(b: *Builder, libraryName: []const u8, sourceFile: []const u8) *LibExeObjStep {
+    const lib = b.addStaticLibrary(libraryName, sourceFile);
+
+    lib.setTheTarget(gbaThumbTarget());
+
+    lib.setLinkerScriptPath(GBALinkerScript);
+    lib.setBuildMode(builtin.Mode.ReleaseFast);
+
+    return lib;
+}
+
+pub fn createGBALib(b: *Builder) *LibExeObjStep {
+    return addGBAStaticLibrary(b, "ZigGBA", "GBA/gba.zig");
+}
+
+pub fn addGBAExecutable(b: *Builder, romName: []const u8, sourceFile: []const u8) *LibExeObjStep {
+    const exe = b.addExecutable(romName, sourceFile);
+
+    exe.setTheTarget(gbaThumbTarget());
+
+    exe.setOutputDir("zig-cache/raw");
+    exe.setLinkerScriptPath(GBALinkerScript);
+    exe.setBuildMode(builtin.Mode.ReleaseFast);
+
+    const gbaLib = createGBALib(b);
+    exe.addPackagePath("gba", "GBA/gba.zig");
+    exe.linkLibrary(gbaLib);
+
+    var allocBuffer: [4 * 1024]u8 = undefined;
+    var fixed = FixedBufferAllocator.init(allocBuffer[0..]);
+    const fixedAllocator = &fixed.allocator;
+
+    const outputPath = fmt.allocPrint(fixedAllocator, "zig-cache/bin/{}.gba", .{romName}) catch unreachable;
+
+    if (fs.path.dirname(outputPath)) |dirPath| {
+        _ = fs.makePath(fixedAllocator, dirPath) catch unreachable;
+    }
+
+    // TODO: Use builtin raw output when available in Zig compiler
+    const objCopyCommand = if (builtin.os == builtin.Os.windows) "C:\\Programmation\\Zig\\llvm+clang-9.0.0-win64-msvc-mt\\bin\\llvm-objcopy.exe" else "llvm-objcopy";
+    const buildGBARomCommand = b.addSystemCommand(&[_][]const u8{
+        objCopyCommand, exe.getOutputPath(),
+        "-O",           "binary",
+        outputPath,
+    });
+
+    buildGBARomCommand.step.dependOn(&exe.step);
+
+    b.default_step.dependOn(&buildGBARomCommand.step);
+
+    return exe;
+}

src/gba.zig → GBA/gba.zig

@@ -131,8 +131,8 @@ pub const GBA = struct {
         pub const Object = 0x1000;
     };
 
-    pub inline fn toNativeColor(comptime red: u32, comptime green: u32, comptime blue: u32) u16 {
-        return @as(u16, (red | (green << 5) | (blue << 10)));
+    pub inline fn toNativeColor(comptime red: u8, comptime green: u8, comptime blue: u8) u16 {
+        return @as(u16, red & 0x1f) | (@as(u16, green & 0x1f) << 5) | (@as(u16, blue & 0x1f) << 10);
     }
 
     pub inline fn setupDisplay(mode: DisplayMode, layers: u32) void {
@@ -158,7 +158,7 @@ pub const GBA = struct {
 
     // TODO: Figure out how to pass the reset flags and don't get eaten up by the optimizer
     pub fn BIOSRegisterRamReset() void {
-        asm volatile(
+        asm volatile (
             \\movs r0, #0xFF
             \\swi 1
         );
@@ -187,5 +187,9 @@ export nakedcc fn GBAMain() noreturn {
     GBA.BIOSRegisterRamReset();
 
     // call user's main
-    root.main();
-}
+    if (@hasDecl(root, "main")) {
+        root.main();
+    } else {
+        while (true) {}
+    }
+}

README.md

@@ -1,19 +1,19 @@
-# Zig GBA "Hello World"
+# Zig GBA
 
-This is a simple GBA program that display 3 color pixel as a hello world to the system. Also a testament to the Zig excellent cross-compile functionality !
+This is a work in progress SDK for creating Game Boy Advance games using [Zig](https://ziglang.org/) programming language. Once Zig has a proper package manager, I hope that it would as easy as import the ZigGBA package. Inspired by [TONC GBA tutorial](https://www.coranac.com/tonc/text/)
 
 ## Build
-This project assume current Zig master (0.5.0+d28aa38db). For now, you need llvm-objcopy in your PATH or change the hardcoded path in build.zig.
+This project assume current Zig master (0.5.0+a3f6a58c7). For now, you need llvm-objcopy in your PATH or change the hardcoded path in GBA/builder.zig.
 
 To build, simply use Zig's integrated build system
 ```Shell
 zig build
 ```
 
-## Running in a emulator
+## First example running in a emulator
 
-![Emulator image](docs/Emulator.png)
+![First example emulator image](docs/images/FirstExampleEmulator.png)
 
-## Running on real hardware
+## First example running on real hardware
 
-![Real hardware image](docs/RealHardware.png)
+![First example real hardware image](docs/images/FirstExampleRealHardware.png)

build.zig

@@ -1,33 +1,6 @@
 const Builder = @import("std").build.Builder;
-const builtin = @import("std").builtin;
-const std = @import("std");
+usingnamespace @import("GBA/builder.zig");
 
 pub fn build(b: *Builder) void {
-    const exe = b.addExecutable("GBAHelloWorld", "src/main.zig");
-
-    exe.setTheTarget(std.Target {
-        .Cross = std.Target.Cross {
-            .arch = std.Target.Arch {
-                .thumb = std.Target.Arch.Arm32.v4t
-            },
-            .os = .freestanding,
-            .abi = .none
-        }
-    });
-
-    exe.setOutputDir("zig-cache/raw");
-    exe.setLinkerScriptPath("gba.ld");
-    exe.setBuildMode(builtin.Mode.ReleaseFast);
-
-    const objCopyCommand = if (builtin.os == builtin.Os.windows) "C:\\Programmation\\Zig\\llvm+clang-9.0.0-win64-msvc-mt\\bin\\llvm-objcopy.exe" else "llvm-objcopy";
-
-    const buildGBARomCommand = b.addSystemCommand(&[_][]const u8 {
-        objCopyCommand, exe.getOutputPath(),
-        "-O", "binary",
-        "zig-cache/bin/GBAHelloWorld.gba",
-    });
-
-    buildGBARomCommand.step.dependOn(&exe.step);
-
-    b.default_step.dependOn(&buildGBARomCommand.step);
+    const first = addGBAExecutable(b, "first", "examples/first/first.zig");
 }

src/main.zig → examples/first/first.zig

@@ -1,6 +1,6 @@
-const GBA = @import("gba.zig").GBA;
+const GBA = @import("gba").GBA;
 
-export var gameHeader linksection(".gbaheader") = GBA.Header.setup("HELLOWORLD", "AWJE", "00", 0);
+export var gameHeader linksection(".gbaheader") = GBA.Header.setup("FIRST", "AFSE", "00", 0);
 
 pub fn main() noreturn {
     GBA.setupDisplay(GBA.DisplayMode.Mode3, GBA.DisplayLayers.Background2 | GBA.DisplayLayers.Background0);