misc: minor cleanup

Ryp · Jun 24, 2024 · 3e43008 · 3e43008
1 parent 176524f
commit 3e43008
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Showing 3 changed files with 10 additions and 13 deletions.
diff --git a/src/gb/cpu.zig b/src/gb/cpu.zig
@@ -326,16 +326,11 @@ pub const MMIO = packed struct {
     },
 };
 
+pub const MMIOSizeBytes = 256;
+
 comptime {
     assert(@offsetOf(MMIO, "apu") == 0x10);
     assert(@offsetOf(MMIO, "ppu") == 0x40);
     assert(@offsetOf(MMIO, "PCM34") == 0x77);
     assert(@sizeOf(MMIO) == MMIOSizeBytes);
 }
-
-pub const MMIOSizeBytes = 256;
-
-pub const TClockPeriod = 4 * 1024 * 1024;
-pub const DIVClockPeriod = 16 * 1024;
-
-pub const DMACopyByteCount = 160;
diff --git a/src/gb/execution.zig b/src/gb/execution.zig
@@ -164,6 +164,8 @@ fn step_timer(gb: *cpu.GBState, clock_falling_edge_mask: u64) void {
     }
 }
 
+const DMACopyByteCount = 160;
+
 fn step_dma(gb: *cpu.GBState, t_cycle_count: u8) void {
     const scope = tracy.trace(@src());
     defer scope.end();
@@ -174,7 +176,7 @@ fn step_dma(gb: *cpu.GBState, t_cycle_count: u8) void {
     // Copy 1 byte per M-cycle
     const byte_count_to_copy_max = t_cycle_count / 4;
     const copy_offset_begin = gb.dma_current_offset;
-    const copy_offset_end = @min(gb.dma_current_offset + byte_count_to_copy_max, cpu.DMACopyByteCount);
+    const copy_offset_end = @min(gb.dma_current_offset + byte_count_to_copy_max, DMACopyByteCount);
 
     for (copy_offset_begin..copy_offset_end) |offset| {
         oam_sprites_mem[offset] = load_memory_u8(gb, dma_src_address + @as(u16, @intCast(offset)));
@@ -183,7 +185,7 @@ fn step_dma(gb: *cpu.GBState, t_cycle_count: u8) void {
     // Update state
     gb.dma_current_offset = copy_offset_end;
 
-    if (copy_offset_end == cpu.DMACopyByteCount) {
+    if (copy_offset_end == DMACopyByteCount) {
         gb.dma_active = false;
     }
 }
@@ -1190,9 +1192,6 @@ const TAC = 0x07; // Timer Control (R/W)
 // PPU Region A
 const DMA = 0x46; // DMA Transfer and Start Address (W)
 // PPU Region B
-// KEY0       = 0x4C, // Controls DMG mode and PGB mode
-// KEY1       = 0x4D, // CGB Mode Only - Prepare Speed Switch
-// VBK        = 0x4F, // CGB Mode Only - VRAM Bank
 // BANK       = 0x50, // Write to disable the boot ROM mapping
 // HDMA1      = 0x51, // CGB Mode Only - New DMA Source, High
 // HDMA2      = 0x52, // CGB Mode Only - New DMA Source, Low

diff --git a/src/gb/ppu.zig b/src/gb/ppu.zig
@@ -125,7 +125,7 @@ pub fn step_ppu(gb: *cpu.GBState, t_cycle_count: u8) void {
 pub const MMIO_OffsetABegin = LCDC;
 pub const MMIO_OffsetAEndInclusive = LYC;
 pub const MMIO_OffsetBBegin = BGP;
-pub const MMIO_OffsetBEndInclusive = WX;
+pub const MMIO_OffsetBEndInclusive = VBK;
 
 pub fn store_mmio_u8(ppu: *PPUState, mmio: *MMIO, mmio_bytes: []u8, offset: u8, value: u8) void {
     switch (offset) {
@@ -511,3 +511,6 @@ const OBP0 = 0x48; // Object Palette 0 Data (R/W) - Non CGB Mode Only
 const OBP1 = 0x49; // Object Palette 1 Data (R/W) - Non CGB Mode Only
 const WY = 0x4A; // Window Y Position (R/W)
 const WX = 0x4B; // Window X Position minus 7 (R/W)
+const KEY0 = 0x4C; // Controls DMG mode and PGB mode
+const KEY1 = 0x4D; // CGB Mode Only - Prepare Speed Switch
+const VBK = 0x4F; // CGB Mode Only - VRAM Bank