fix: impl BG?{X,Y} RefPoint write behaviour outside of Vblank

With this fix Mode 7-like games now properly render their backgrounds

src/bus/GamePak.zig

@@ -113,14 +113,14 @@ pub fn write(self: *Self, comptime T: type, word_count: u16, address: u32, value
 
     switch (T) {
         u32 => switch (address) {
-            0x0800_00C4 => log.err("Wrote {} 0x{X:} to I/O Port Data and Direction", .{ T, value }),
+            0x0800_00C4 => log.debug("Wrote {} 0x{X:} to I/O Port Data and Direction", .{ T, value }),
-            0x0800_00C6 => log.err("Wrote {} 0x{X:} to I/O Port Direction and Control", .{ T, value }),
+            0x0800_00C6 => log.debug("Wrote {} 0x{X:} to I/O Port Direction and Control", .{ T, value }),
             else => {},
         },
         u16 => switch (address) {
-            0x0800_00C4 => log.err("Wrote {} 0x{X:} to I/O Port Data", .{ T, value }),
+            0x0800_00C4 => log.debug("Wrote {} 0x{X:} to I/O Port Data", .{ T, value }),
-            0x0800_00C6 => log.err("Wrote {} 0x{X:} to I/O Port Direction", .{ T, value }),
+            0x0800_00C6 => log.debug("Wrote {} 0x{X:} to I/O Port Direction", .{ T, value }),
-            0x0800_00C8 => log.err("Wrote {} 0x{X:} to I/O Port Control", .{ T, value }),
+            0x0800_00C8 => log.debug("Wrote {} 0x{X:} to I/O Port Control", .{ T, value }),
             else => {},
         },
         u8 => log.debug("Wrote {} 0x{X:} to 0x{X:0>8}, Ignored.", .{ T, value, address }),

src/bus/io.zig

@@ -156,12 +156,12 @@ 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 = @bitCast(i32, value),
+            0x0400_0028 => bus.ppu.aff_bg[0].setX(bus.ppu.dispstat.vblank.read(), value),
-            0x0400_002C => bus.ppu.aff_bg[0].y = @bitCast(i32, value),
+            0x0400_002C => bus.ppu.aff_bg[0].setY(bus.ppu.dispstat.vblank.read(), 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 = @bitCast(i32, value),
+            0x0400_0038 => bus.ppu.aff_bg[1].setX(bus.ppu.dispstat.vblank.read(), value),
-            0x0400_003C => bus.ppu.aff_bg[1].y = @bitCast(i32, value),
+            0x0400_003C => bus.ppu.aff_bg[1].setY(bus.ppu.dispstat.vblank.read(), 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}),

src/ppu.zig

@@ -752,6 +752,16 @@ const AffineBackground = struct {
         };
     }
 
+    pub fn setX(self: *Self, is_vblank: bool, value: u32) void {
+        self.x = @bitCast(i32, value);
+        if (!is_vblank) self.x_latch = @bitCast(i32, value);
+    }
+
+    pub fn setY(self: *Self, is_vblank: bool, value: u32) void {
+        self.y = @bitCast(i32, value);
+        if (!is_vblank) self.y_latch = @bitCast(i32, value);
+    }
+
     pub fn writePaPb(self: *Self, value: u32) void {
         self.pa = @bitCast(i16, @truncate(u16, value));
         self.pb = @bitCast(i16, @truncate(u16, value >> 16));

src/util.zig

@@ -102,13 +102,13 @@ pub const FilePaths = struct {
 };
 
 pub fn readUndefined(log: anytype, comptime format: []const u8, args: anytype) u8 {
-    log.debug(format, args);
+    log.warn(format, args);
     if (builtin.mode == .Debug) std.debug.panic("TODO: Implement I/O Register", .{});
 
     return 0;
 }
 
 pub fn writeUndefined(log: anytype, comptime format: []const u8, args: anytype) void {
-    log.debug(format, args);
+    log.warn(format, args);
     if (builtin.mode == .Debug) std.debug.panic("TODO: Implement I/O Register", .{});
 }