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fix: replace affine bg register bitfields with signed integers

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-06-03 19:26:52 -03:00
parent 2dc3864dca
commit b6f5517c89
2 changed files with 59 additions and 50 deletions
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54
src/bus/io.zig
View File

@ -184,12 +184,12 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
0x0400_001C => bus.ppu.setBgOffsets(3, value),
0x0400_0020 => bus.ppu.aff.bg[0].writePaPb(value),
0x0400_0024 => bus.ppu.aff.bg[0].writePcPd(value),
0x0400_0028 => bus.ppu.aff.bg[0].x.raw = value,
0x0400_002C => bus.ppu.aff.bg[0].y.raw = value,
0x0400_0028 => bus.ppu.aff.bg[0].x = @bitCast(i32, value),
0x0400_002C => bus.ppu.aff.bg[0].y = @bitCast(i32, value),
0x0400_0030 => bus.ppu.aff.bg[1].writePaPb(value),
0x0400_0034 => bus.ppu.aff.bg[1].writePcPd(value),
0x0400_0038 => bus.ppu.aff.bg[1].x.raw = value,
0x0400_003C => bus.ppu.aff.bg[1].y.raw = value,
0x0400_0038 => bus.ppu.aff.bg[1].x = @bitCast(i32, value),
0x0400_003C => bus.ppu.aff.bg[1].y = @bitCast(i32, value),
0x0400_0040 => log.debug("Wrote 0x{X:0>8} to WIN0H and WIN1H", .{value}),
0x0400_0044 => log.debug("Wrote 0x{X:0>8} to WIN0V and WIN1V", .{value}),
0x0400_0048 => log.debug("Wrote 0x{X:0>8} to WININ and WINOUT", .{value}),
@ -270,22 +270,22 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
0x0400_001A => bus.ppu.bg[2].vofs.raw = value,
0x0400_001C => bus.ppu.bg[3].hofs.raw = value,
0x0400_001E => bus.ppu.bg[3].vofs.raw = value,
0x0400_0020 => bus.ppu.aff.bg[0].pa.raw = value,
0x0400_0022 => bus.ppu.aff.bg[0].pb.raw = value,
0x0400_0024 => bus.ppu.aff.bg[0].pc.raw = value,
0x0400_0026 => bus.ppu.aff.bg[0].pd.raw = value,
0x0400_0028 => bus.ppu.aff.bg[0].x.raw = bus.ppu.aff.bg[0].x.raw & 0xFFFF_0000 | value,
0x0400_002A => bus.ppu.aff.bg[0].x.raw = bus.ppu.aff.bg[0].x.raw & 0x0000_FFFF | (@as(u32, value) << 16),
0x0400_002C => bus.ppu.aff.bg[0].y.raw = bus.ppu.aff.bg[0].y.raw & 0xFFFF_0000 | value,
0x0400_002E => bus.ppu.aff.bg[0].y.raw = bus.ppu.aff.bg[0].y.raw & 0x0000_FFFF | (@as(u32, value) << 16),
0x0400_0030 => bus.ppu.aff.bg[1].pa.raw = value,
0x0400_0032 => bus.ppu.aff.bg[1].pb.raw = value,
0x0400_0034 => bus.ppu.aff.bg[1].pc.raw = value,
0x0400_0036 => bus.ppu.aff.bg[1].pd.raw = value,
0x0400_0038 => bus.ppu.aff.bg[1].x.raw = bus.ppu.aff.bg[1].x.raw & 0xFFFF_0000 | value,
0x0400_003A => bus.ppu.aff.bg[1].x.raw = bus.ppu.aff.bg[1].x.raw & 0x0000_FFFF | (@as(u32, value) << 16),
0x0400_003C => bus.ppu.aff.bg[1].y.raw = bus.ppu.aff.bg[1].y.raw & 0xFFFF_0000 | value,
0x0400_003E => bus.ppu.aff.bg[1].y.raw = bus.ppu.aff.bg[1].y.raw & 0x0000_FFFF | (@as(u32, value) << 16),
0x0400_0020 => bus.ppu.aff.bg[0].pa = @bitCast(i16, value),
0x0400_0022 => bus.ppu.aff.bg[0].pb = @bitCast(i16, value),
0x0400_0024 => bus.ppu.aff.bg[0].pc = @bitCast(i16, value),
0x0400_0026 => bus.ppu.aff.bg[0].pd = @bitCast(i16, value),
0x0400_0028 => bus.ppu.aff.bg[0].x = @bitCast(i32, @bitCast(u32, bus.ppu.aff.bg[0].x) & 0xFFFF_0000 | value),
0x0400_002A => bus.ppu.aff.bg[0].x = @bitCast(i32, @bitCast(u32, bus.ppu.aff.bg[0].x) & 0x0000_FFFF | (@as(u32, value) << 16)),
0x0400_002C => bus.ppu.aff.bg[0].y = @bitCast(i32, @bitCast(u32, bus.ppu.aff.bg[0].y) & 0xFFFF_0000 | value),
0x0400_002E => bus.ppu.aff.bg[0].y = @bitCast(i32, @bitCast(u32, bus.ppu.aff.bg[0].y) & 0x0000_FFFF | (@as(u32, value) << 16)),
0x0400_0030 => bus.ppu.aff.bg[1].pa = @bitCast(i16, value),
0x0400_0032 => bus.ppu.aff.bg[1].pb = @bitCast(i16, value),
0x0400_0034 => bus.ppu.aff.bg[1].pc = @bitCast(i16, value),
0x0400_0036 => bus.ppu.aff.bg[1].pd = @bitCast(i16, value),
0x0400_0038 => bus.ppu.aff.bg[1].x = @bitCast(i32, @bitCast(u32, bus.ppu.aff.bg[1].x) & 0xFFFF_0000 | value),
0x0400_003A => bus.ppu.aff.bg[1].x = @bitCast(i32, @bitCast(u32, bus.ppu.aff.bg[1].x) & 0x0000_FFFF | (@as(u32, value) << 16)),
0x0400_003C => bus.ppu.aff.bg[1].y = @bitCast(i32, @bitCast(u32, bus.ppu.aff.bg[1].y) & 0xFFFF_0000 | value),
0x0400_003E => bus.ppu.aff.bg[1].y = @bitCast(i32, @bitCast(u32, bus.ppu.aff.bg[1].y) & 0x0000_FFFF | (@as(u32, value) << 16)),
0x0400_0040 => log.debug("Wrote 0x{X:0>4} to WIN0H", .{value}),
0x0400_0042 => log.debug("Wrote 0x{X:0>4} to WIN1H", .{value}),
0x0400_0044 => log.debug("Wrote 0x{X:0>4} to WIN0V", .{value}),
@ -561,20 +561,6 @@ pub const BackgroundOffset = extern union {
raw: u16,
};
pub const BackgroundRefPoint = extern union {
fractional: Bitfield(u32, 0, 8),
integer: Bitfield(u32, 8, 19),
sign: Bit(u32, 27),
raw: u32,
};
pub const BackgroundRotScaleParam = extern union {
fractional: Bitfield(u16, 0, 8),
integer: Bitfield(u16, 8, 7),
sign: Bit(u32, 15),
raw: u16,
};
/// Read / Write
const InterruptRequest = extern union {
vblank: Bit(u16, 0),

55
src/ppu.zig
View File

@ -201,6 +201,14 @@ pub const Ppu = struct {
if (pal_id != 0) self.scanline_buf[@bitCast(u9, x)] = self.palette.read(u16, 0x200 + pal_id * 2);
}
fn drawAffineBackground(self: *Self, comptime n: u3) void {
comptime std.debug.assert(n == 2 or n == 3); // Only BG2 and BG3 can be affine
// Update BG?X/Y
self.aff.bg[n - 2].x_latch += self.aff.bg[n - 2].pb >> 8;
self.aff.bg[n - 2].y_latch += self.aff.bg[n - 2].pc >> 8;
}
fn drawBackround(self: *Self, comptime n: u3) void {
// A Tile in a charblock is a byte, while a Screen Entry is a halfword
const charblock_len: u32 = 0x4000;
@ -458,6 +466,9 @@ pub const Ppu = struct {
cpu.handleInterrupt();
}
self.aff.bg[0].latchRefPoints();
self.aff.bg[1].latchRefPoints();
// See if Vblank DMA is present and not enabled
pollBlankingDma(&cpu.bus, .VBlank);
}
@ -656,33 +667,45 @@ const AffineBackground = struct {
const AffineBackgroundRegisters = struct {
const Self = @This();
x: io.BackgroundRefPoint,
y: io.BackgroundRefPoint,
x: i32,
y: i32,
pa: io.BackgroundRotScaleParam,
pb: io.BackgroundRotScaleParam,
pc: io.BackgroundRotScaleParam,
pd: io.BackgroundRotScaleParam,
pa: i16,
pb: i16,
pc: i16,
pd: i16,
x_latch: ?i32,
y_latch: ?i32,
fn init() Self {
return .{
.x = .{ .raw = 0 },
.y = .{ .raw = 0 },
.pa = .{ .raw = 0 },
.pb = .{ .raw = 0 },
.pc = .{ .raw = 0 },
.pd = .{ .raw = 0 },
.x = 0,
.y = 0,
.pa = 0,
.pb = 0,
.pc = 0,
.pd = 0,
.x_latch = null,
.y_latch = null,
};
}
pub fn writePaPb(self: *Self, value: u32) void {
self.pa.raw = @truncate(u16, value);
self.pb.raw = @truncate(u16, value >> 16);
self.pa = @bitCast(i16, @truncate(u16, value));
self.pb = @bitCast(i16, @truncate(u16, value >> 16));
}
pub fn writePcPd(self: *Self, value: u32) void {
self.pc.raw = @truncate(u16, value);
self.pd.raw = @truncate(u16, value >> 16);
self.pc = @bitCast(i16, @truncate(u16, value));
self.pd = @bitCast(i16, @truncate(u16, value >> 16));
}
// Every Vblank BG?X/Y registers are latched
fn latchRefPoints(self: *Self) void {
self.x_latch = self.x;
self.y_latch = self.y;
}
};