feat(bus): emu is now able to read from user-provided BIOS

src/bus/bios.zig

@@ -0,0 +1,30 @@
+const std = @import("std");
+
+const Allocator = std.mem.Allocator;
+
+pub const Bios = struct {
+    buf: []u8,
+
+    pub fn fromPath(alloc: Allocator, path: []const u8) !@This() {
+        const file = try std.fs.cwd().openFile(path, .{ .read = true });
+        defer file.close();
+
+        const len = try file.getEndPos();
+
+        return @This(){
+            .buf = try file.readToEndAlloc(alloc, len),
+        };
+    }
+
+    pub inline fn get32(self: *const @This(), idx: usize) u32 {
+        return (@as(u32, self.buf[idx + 3]) << 24) | (@as(u32, self.buf[idx + 2]) << 16) | (@as(u32, self.buf[idx + 1]) << 8) | (@as(u32, self.buf[idx]));
+    }
+
+    pub inline fn get16(self: *const @This(), idx: usize) u16 {
+        return (@as(u16, self.buf[idx + 1]) << 8) | @as(u16, self.buf[idx]);
+    }
+
+    pub inline fn get8(self: *const @This(), idx: usize) u8 {
+        return self.buf[idx];
+    }
+};

src/bus/pak.zig

@@ -0,0 +1,30 @@
+const std = @import("std");
+
+const Allocator = std.mem.Allocator;
+
+pub const GamePak = struct {
+    buf: []u8,
+
+    pub fn fromPath(alloc: Allocator, path: []const u8) !@This() {
+        const file = try std.fs.cwd().openFile(path, .{ .read = true });
+        defer file.close();
+
+        const len = try file.getEndPos();
+
+        return @This(){
+            .buf = try file.readToEndAlloc(alloc, len),
+        };
+    }
+
+    pub inline fn get32(self: *const @This(), idx: usize) u32 {
+        return (@as(u32, self.buf[idx + 3]) << 24) | (@as(u32, self.buf[idx + 2]) << 16) | (@as(u32, self.buf[idx + 1]) << 8) | (@as(u32, self.buf[idx]));
+    }
+
+    pub inline fn get16(self: *const @This(), idx: usize) u16 {
+        return (@as(u16, self.buf[idx + 1]) << 8) | @as(u16, self.buf[idx]);
+    }
+
+    pub inline fn get8(self: *const @This(), idx: usize) u8 {
+        return self.buf[idx];
+    }
+};