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feat(ppu): implement all ppu i/o reads

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-10-29 01:08:58 -03:00
parent d859cee365
commit 3e62feacba
3 changed files with 45 additions and 12 deletions
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1
src/core/Bus.zig
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@ -112,6 +112,7 @@ pub fn dbgRead(self: *const Self, comptime T: type, address: u32) T {
};
}
/// TODO: Should open bus read addresses be force-aligned?
fn readIo(self: *const Self, comptime T: type, unaligned_address: u32) T {
const maybe_value = io.read(self, T, forceAlign(T, unaligned_address));
return if (maybe_value) |value| value else self.openBus(T, unaligned_address);

54
src/core/ppu.zig
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@ -24,40 +24,70 @@ pub fn read(comptime T: type, ppu: *const Ppu, addr: u32) ?T {
return switch (T) {
u32 => switch (byte) {
0x00 => ppu.dispcnt.raw,
0x00 => ppu.dispcnt.raw, // Green Swap is in high half-word
0x04 => @as(T, ppu.vcount.raw) << 16 | ppu.dispstat.raw,
0x06 => @as(T, ppu.bg[0].cnt.raw) << 16 | ppu.vcount.raw,
0x08 => @as(T, ppu.bg[1].cnt.raw) << 16 | ppu.bg[0].cnt.raw,
0x0C => @as(T, ppu.bg[3].cnt.raw) << 16 | ppu.bg[2].cnt.raw,
0x10...0x1C => null, // BGXHOFS/VOFS
0x20...0x3C => null, // BG2/3 Rot Scaling Registers
0x40...0x44 => null, // WINXH/V Registers
0x48 => @as(T, ppu.win.out.raw) << 16 | ppu.win.in.raw,
0x4C => null, // MOSAIC, undefined in high byte
0x50 => @as(T, ppu.bldalpha.raw) << 16 | ppu.bldcnt.raw,
0x54 => null, // BLDY, undefined in high half-wrd
else => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, addr }),
},
u16 => switch (byte) {
0x00 => ppu.dispcnt.raw,
0x02 => null, // Green Swap
0x04 => ppu.dispstat.raw,
0x06 => ppu.vcount.raw,
0x08 => ppu.bg[0].cnt.raw,
0x0A => ppu.bg[1].cnt.raw,
0x0C => ppu.bg[2].cnt.raw,
0x0E => ppu.bg[3].cnt.raw,
0x4C => util.io.read.todo(log, "Read {} from MOSAIC", .{T}),
0x10...0x1E => null, // BGXHOFS/VOFS
0x20...0x3E => null, // BG2/3 Rot Scaling Registers
0x40...0x46 => null, // WINXH/V Registers
0x48 => ppu.win.in.raw,
0x4A => ppu.win.out.raw,
0x4C => null, // MOSAIC
0x50 => ppu.bldcnt.raw,
0x52 => ppu.bldalpha.raw,
0x54 => ppu.bldy.raw,
0x54 => null, // BLDY
else => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, addr }),
},
u8 => switch (byte) {
0x00 => @truncate(T, ppu.dispcnt.raw),
0x04 => @truncate(T, ppu.dispstat.raw),
0x05 => @truncate(T, ppu.dispcnt.raw >> 8),
0x06 => @truncate(T, ppu.vcount.raw),
0x08 => @truncate(T, ppu.bg[0].cnt.raw),
0x09 => @truncate(T, ppu.bg[0].cnt.raw >> 8),
0x0A => @truncate(T, ppu.bg[1].cnt.raw),
0x0B => @truncate(T, ppu.bg[1].cnt.raw >> 8),
0x00...0x01 => @truncate(T, ppu.dispcnt.raw >> shift(byte)),
0x02...0x03 => null,
0x04...0x05 => @truncate(T, ppu.dispstat.raw >> shift(byte)),
0x06...0x07 => @truncate(T, ppu.vcount.raw >> shift(byte)),
0x08...0x09 => @truncate(T, ppu.bg[0].cnt.raw >> shift(byte)),
0x0A...0x0B => @truncate(T, ppu.bg[1].cnt.raw >> shift(byte)),
0x0C...0x0D => @truncate(T, ppu.bg[2].cnt.raw >> shift(byte)),
0x0E...0x0F => @truncate(T, ppu.bg[3].cnt.raw >> shift(byte)),
0x10...0x1F => null, // BGXHOFS/VOFS
0x20...0x3F => null, // BG2/3 Rot Scaling Registers
0x40...0x47 => null, // WINXH/V Registers
0x48...0x49 => @truncate(T, ppu.win.in.raw >> shift(byte)),
0x4A...0x4B => @truncate(T, ppu.win.out.raw >> shift(byte)),
0x4C...0x4D => null, // MOSAIC
0x50...0x51 => @truncate(T, ppu.bldcnt.raw >> shift(byte)),
0x52...0x53 => @truncate(T, ppu.bldalpha.raw >> shift(byte)),
0x54...0x55 => null, // BLDY
else => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, addr }),
},
else => @compileError("PPU: Unsupported read width"),
};
}
/// Calculates the correct shift offset for an aligned/unaligned u8 read
///
/// TODO: Rename this
inline fn shift(byte: u8) u4 {
return @truncate(u4, byte & 1) << 3;
}
pub fn write(comptime T: type, ppu: *Ppu, addr: u32, value: T) void {
const byte = @truncate(u8, addr); // prefixed with 0x0400_00

2
src/util.zig
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@ -144,6 +144,8 @@ pub const io = struct {
}
pub fn undef(comptime T: type, log: anytype, comptime format: []const u8, args: anytype) ?T {
@setCold(true);
const unhandled_io = config.config().debug.unhandled_io;
log.warn(format, args);