diff --git a/src/Bus.zig b/src/Bus.zig index 91162ea..5c5a493 100644 --- a/src/Bus.zig +++ b/src/Bus.zig @@ -61,7 +61,7 @@ pub fn read32(self: *const Self, addr: u32) u32 { // Internal Display Memory 0x0500_0000...0x05FF_FFFF => self.ppu.palette.get32(addr & 0x3FF), - 0x0600_0000...0x0601_7FFF => self.ppu.vram.read(u32, addr - 0x0600_0000), + 0x0600_0000...0x06FF_FFFF => self.ppu.vram.read(u32, addr), 0x0700_0000...0x07FF_FFFF => self.ppu.oam.get32(addr & 0x3FF), // External Memory (Game Pak) @@ -84,7 +84,7 @@ pub fn write32(self: *Self, addr: u32, word: u32) void { // Internal Display Memory 0x0500_0000...0x05FF_FFFF => self.ppu.palette.set32(addr & 0x3FF, word), - 0x0600_0000...0x0601_7FFF => self.ppu.vram.write(u32, addr - 0x0600_0000, word), + 0x0600_0000...0x06FF_FFFF => self.ppu.vram.write(u32, addr, word), 0x0700_0000...0x07FF_FFFF => self.ppu.oam.set32(addr & 0x3FF, word), else => undWrite("Tried to write 0x{X:0>8} to 0x{X:0>8}", .{ word, addr }), @@ -101,7 +101,7 @@ pub fn read16(self: *const Self, addr: u32) u16 { // Internal Display Memory 0x0500_0000...0x05FF_FFFF => self.ppu.palette.get16(addr & 0x3FF), - 0x0600_0000...0x0601_7FFF => self.ppu.vram.read(u16, addr - 0x0600_0000), + 0x0600_0000...0x06FF_FFFF => self.ppu.vram.read(u16, addr), 0x0700_0000...0x07FF_FFFF => self.ppu.oam.get16(addr & 0x3FF), // External Memory (Game Pak) @@ -123,7 +123,7 @@ pub fn write16(self: *Self, addr: u32, halfword: u16) void { // Internal Display Memory 0x0500_0000...0x05FF_FFFF => self.ppu.palette.set16(addr & 0x3FF, halfword), - 0x0600_0000...0x0601_7FFF => self.ppu.vram.write(u16, addr - 0x0600_0000, halfword), + 0x0600_0000...0x06FF_FFFF => self.ppu.vram.write(u16, addr, halfword), 0x0700_0000...0x07FF_FFFF => self.ppu.oam.set16(addr & 0x3FF, halfword), 0x0800_00C4, 0x0800_00C6, 0x0800_00C8 => log.warn("Tried to write 0x{X:0>4} to GPIO", .{halfword}), @@ -141,7 +141,7 @@ pub fn read8(self: *const Self, addr: u32) u8 { // Internal Display Memory 0x0500_0000...0x05FF_FFFF => self.ppu.palette.get8(addr & 0x3FF), - 0x0600_0000...0x0601_7FFF => self.ppu.vram.read(u8, addr - 0x0600_0000), + 0x0600_0000...0x06FF_FFFF => self.ppu.vram.read(u8, addr), 0x0700_0000...0x07FF_FFFF => self.ppu.oam.get8(addr & 0x3FF), // External Memory (Game Pak) diff --git a/src/ppu.zig b/src/ppu.zig index 5fb37d3..64f8efc 100644 --- a/src/ppu.zig +++ b/src/ppu.zig @@ -479,16 +479,20 @@ const Vram = struct { self.alloc.free(self.buf); } - pub fn read(self: *const Self, comptime T: type, addr: usize) T { - switch (T) { - u32 => return (@as(T, self.buf[addr + 3]) << 24) | (@as(T, self.buf[addr + 2]) << 16) | (@as(T, self.buf[addr + 1]) << 8) | (@as(T, self.buf[addr])), - u16 => return (@as(T, self.buf[addr + 1]) << 8) | @as(T, self.buf[addr]), - u8 => return self.buf[addr], + pub fn read(self: *const Self, comptime T: type, address: usize) T { + const addr = Self.mirror(address); + + return switch (T) { + u32 => (@as(T, self.buf[addr + 3]) << 24) | (@as(T, self.buf[addr + 2]) << 16) | (@as(T, self.buf[addr + 1]) << 8) | (@as(T, self.buf[addr])), + u16 => (@as(T, self.buf[addr + 1]) << 8) | @as(T, self.buf[addr]), + u8 => self.buf[addr], else => @compileError("VRAM: Unsupported read width"), - } + }; } - pub fn write(self: *Self, comptime T: type, addr: usize, value: T) void { + pub fn write(self: *Self, comptime T: type, address: usize, value: T) void { + const addr = Self.mirror(address); + switch (T) { u32 => { self.buf[addr + 3] = @truncate(u8, value >> 24); @@ -503,6 +507,11 @@ const Vram = struct { else => @compileError("VRAM: Unsupported write width"), } } + + fn mirror(address: usize) usize { + const addr = address & 0x1FFFF; // repeated in steps of 128KiB + return if (addr >= 0x18000) addr & 0x7FFF else addr; // 64K + 32K + 32K (abcc) + } }; const Oam = struct {