chore: dont allocate not-small ?Sprite array on stack

use memset like most other allocations in this emu

src/core/bus/dma.zig

@@ -266,7 +266,7 @@ fn DmaController(comptime id: u2) type {
     };
 }
 
-pub fn pollDmaOnBlank(bus: *Bus, comptime kind: DmaKind) void {
+pub fn onBlanking(bus: *Bus, comptime kind: DmaKind) void {
     bus.dma[0].poll(kind);
     bus.dma[1].poll(kind);
     bus.dma[2].poll(kind);

src/core/bus/io.zig

@@ -305,11 +305,21 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
             0x0400_0009 => bus.ppu.bg[0].cnt.raw = setHi(u16, bus.ppu.bg[0].cnt.raw, value),
             0x0400_000A => bus.ppu.bg[1].cnt.raw = setLo(u16, bus.ppu.bg[1].cnt.raw, value),
             0x0400_000B => bus.ppu.bg[1].cnt.raw = setHi(u16, bus.ppu.bg[1].cnt.raw, value),
+            0x0400_0040 => bus.ppu.win.h[0].raw = setLo(u16, bus.ppu.win.h[0].raw, value),
+            0x0400_0041 => bus.ppu.win.h[0].raw = setHi(u16, bus.ppu.win.h[0].raw, value),
+            0x0400_0042 => bus.ppu.win.h[1].raw = setLo(u16, bus.ppu.win.h[1].raw, value),
+            0x0400_0043 => bus.ppu.win.h[1].raw = setHi(u16, bus.ppu.win.h[1].raw, value),
+            0x0400_0044 => bus.ppu.win.v[0].raw = setLo(u16, bus.ppu.win.v[0].raw, value),
+            0x0400_0045 => bus.ppu.win.v[0].raw = setHi(u16, bus.ppu.win.v[0].raw, value),
+            0x0400_0046 => bus.ppu.win.v[1].raw = setLo(u16, bus.ppu.win.v[1].raw, value),
+            0x0400_0047 => bus.ppu.win.v[1].raw = setHi(u16, bus.ppu.win.v[1].raw, value),
             0x0400_0048 => bus.ppu.win.in.raw = setLo(u16, bus.ppu.win.in.raw, value),
             0x0400_0049 => bus.ppu.win.in.raw = setHi(u16, bus.ppu.win.in.raw, value),
             0x0400_004A => bus.ppu.win.out.raw = setLo(u16, bus.ppu.win.out.raw, value),
             0x0400_0054 => bus.ppu.bldy.raw = setLo(u16, bus.ppu.bldy.raw, value),
 
+            
+
             // Sound
             0x0400_0060...0x0400_00A7 => apu.write(T, &bus.apu, address, value),
 
@@ -462,8 +472,12 @@ pub const BldY = extern union {
     raw: u16,
 };
 
+const u8WriteKind = enum { Hi, Lo };
+
 /// Write-only
 pub const WinH = extern union {
+    const Self = @This();
+
     x2: Bitfield(u16, 0, 8),
     x1: Bitfield(u16, 8, 8),
     raw: u16,
@@ -471,9 +485,18 @@ pub const WinH = extern union {
 
 /// Write-only
 pub const WinV = extern union {
+    const Self = @This();
+
     y2: Bitfield(u16, 0, 8),
     y1: Bitfield(u16, 8, 8),
     raw: u16,
+
+    pub fn set(self: *Self, comptime K: u8WriteKind, value: u8) void {
+        self.raw = switch (K) {
+            .Hi => (@as(u16, value) << 8) | self.raw & 0xFF,
+            .Lo => (self.raw & 0xFF00) | value,
+        };
+    }
 };
 
 pub const WinIn = extern union {

src/core/ppu.zig

@@ -1,16 +1,19 @@
 const std = @import("std");
 const io = @import("bus/io.zig");
+const Bit = @import("bitfield").Bit;
+const Bitfield = @import("bitfield").Bitfield;
+const dma = @import("bus/dma.zig");
 
+const Oam = @import("ppu/Oam.zig");
+const Palette = @import("ppu/Palette.zig");
+const Vram = @import("ppu/Vram.zig");
 const EventKind = @import("scheduler.zig").EventKind;
 const Scheduler = @import("scheduler.zig").Scheduler;
 const Arm7tdmi = @import("cpu.zig").Arm7tdmi;
-
-const Bit = @import("bitfield").Bit;
-const Bitfield = @import("bitfield").Bitfield;
+const FrameBuffer = @import("../util.zig").FrameBuffer;
 
 const Allocator = std.mem.Allocator;
 const log = std.log.scoped(.PPU);
-const pollDmaOnBlank = @import("bus/dma.zig").pollDmaOnBlank;
 
 pub const width = 240;
 pub const height = 160;
@@ -48,14 +51,14 @@ pub const Ppu = struct {
         sched.push(.Draw, 240 * 4);
 
         const sprites = try allocator.create([128]?Sprite);
-        sprites.* = [_]?Sprite{null} ** 128;
+        std.mem.set(?Sprite, sprites, null);
 
         return Self{
             .vram = try Vram.init(allocator),
             .palette = try Palette.init(allocator),
             .oam = try Oam.init(allocator),
             .sched = sched,
-            .framebuf = try FrameBuffer.init(allocator),
+            .framebuf = try FrameBuffer.init(allocator, framebuf_pitch * height),
             .allocator = allocator,
 
             // Registers
@@ -485,7 +488,7 @@ pub const Ppu = struct {
                 while (i < width) : (i += 1) {
                     // If we're outside of the bounds of mode 5, draw the background colour
                     const bgr555 =
-                        if (scanline < m5_height and i < m5_width) self.vram.read(u16, vram_base + i * @sizeOf(u16)) else self.palette.getBackdrop();
+                        if (scanline < m5_height and i < m5_width) self.vram.read(u16, vram_base + i * @sizeOf(u16)) else self.palette.backdrop();
 
                     std.mem.writeIntNative(u32, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..@sizeOf(u32)], rgba888(bgr555));
                 }
@@ -529,7 +532,7 @@ pub const Ppu = struct {
         }
 
         if (maybe_top) |top| return top;
-        return self.palette.getBackdrop();
+        return self.palette.backdrop();
     }
 
     fn copyToBackgroundBuffer(self: *Self, comptime n: u2, bounds: ?WindowBounds, i: usize, bgr555: u16) void {
@@ -658,7 +661,7 @@ pub const Ppu = struct {
         // See if HBlank DMA is present and not enabled
 
         if (!self.dispstat.vblank.read())
-            pollDmaOnBlank(cpu.bus, .HBlank);
+            dma.onBlanking(cpu.bus, .HBlank);
 
         self.dispstat.hblank.set();
         self.sched.push(.HBlank, 68 * 4 -| late);
@@ -700,7 +703,7 @@ pub const Ppu = struct {
                 self.aff_bg[1].latchRefPoints();
 
                 // See if Vblank DMA is present and not enabled
-                pollDmaOnBlank(cpu.bus, .VBlank);
+                dma.onBlanking(cpu.bus, .VBlank);
             }
 
             if (scanline == 227) self.dispstat.vblank.unset();
@@ -709,158 +712,6 @@ pub const Ppu = struct {
     }
 };
 
-const Palette = struct {
-    const palram_size = 0x400;
-    const Self = @This();
-
-    buf: []u8,
-    allocator: Allocator,
-
-    fn init(allocator: Allocator) !Self {
-        const buf = try allocator.alloc(u8, palram_size);
-        std.mem.set(u8, buf, 0);
-
-        return Self{
-            .buf = buf,
-            .allocator = allocator,
-        };
-    }
-
-    fn deinit(self: *Self) void {
-        self.allocator.free(self.buf);
-        self.* = undefined;
-    }
-
-    pub fn read(self: *const Self, comptime T: type, address: usize) T {
-        const addr = address & 0x3FF;
-
-        return switch (T) {
-            u32, u16, u8 => std.mem.readIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)]),
-            else => @compileError("PALRAM: Unsupported read width"),
-        };
-    }
-
-    pub fn write(self: *Self, comptime T: type, address: usize, value: T) void {
-        const addr = address & 0x3FF;
-
-        switch (T) {
-            u32, u16 => std.mem.writeIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)], value),
-            u8 => {
-                const align_addr = addr & ~@as(u32, 1); // Aligned to Halfword boundary
-                std.mem.writeIntSliceLittle(u16, self.buf[align_addr..][0..@sizeOf(u16)], @as(u16, value) * 0x101);
-            },
-            else => @compileError("PALRAM: Unsupported write width"),
-        }
-    }
-
-    fn getBackdrop(self: *const Self) u16 {
-        return self.read(u16, 0);
-    }
-};
-
-const Vram = struct {
-    const vram_size = 0x18000;
-    const Self = @This();
-
-    buf: []u8,
-    allocator: Allocator,
-
-    fn init(allocator: Allocator) !Self {
-        const buf = try allocator.alloc(u8, vram_size);
-        std.mem.set(u8, buf, 0);
-
-        return Self{
-            .buf = buf,
-            .allocator = allocator,
-        };
-    }
-
-    fn deinit(self: *Self) void {
-        self.allocator.free(self.buf);
-        self.* = undefined;
-    }
-
-    pub fn read(self: *const Self, comptime T: type, address: usize) T {
-        const addr = Self.mirror(address);
-
-        return switch (T) {
-            u32, u16, u8 => std.mem.readIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)]),
-            else => @compileError("VRAM: Unsupported read width"),
-        };
-    }
-
-    pub fn write(self: *Self, comptime T: type, dispcnt: io.DisplayControl, address: usize, value: T) void {
-        const mode: u3 = dispcnt.bg_mode.read();
-        const idx = Self.mirror(address);
-
-        switch (T) {
-            u32, u16 => std.mem.writeIntSliceLittle(T, self.buf[idx..][0..@sizeOf(T)], value),
-            u8 => {
-                // Ignore write if it falls within the boundaries of OBJ VRAM
-                switch (mode) {
-                    0, 1, 2 => if (0x0001_0000 <= idx) return,
-                    else => if (0x0001_4000 <= idx) return,
-                }
-
-                const align_idx = idx & ~@as(u32, 1); // Aligned to a halfword boundary
-                std.mem.writeIntSliceLittle(u16, self.buf[align_idx..][0..@sizeOf(u16)], @as(u16, value) * 0x101);
-            },
-            else => @compileError("VRAM: Unsupported write width"),
-        }
-    }
-
-    fn mirror(address: usize) usize {
-        // Mirrored in steps of 128K (64K + 32K + 32K) (abcc)
-        const addr = address & 0x1FFFF;
-
-        // If the address is within 96K we don't do anything,
-        // otherwise we want to mirror the last 32K (addresses between 64K and 96K)
-        return if (addr < vram_size) addr else 0x10000 + (addr & 0x7FFF);
-    }
-};
-
-const Oam = struct {
-    const oam_size = 0x400;
-    const Self = @This();
-
-    buf: []u8,
-    allocator: Allocator,
-
-    fn init(allocator: Allocator) !Self {
-        const buf = try allocator.alloc(u8, oam_size);
-        std.mem.set(u8, buf, 0);
-
-        return Self{
-            .buf = buf,
-            .allocator = allocator,
-        };
-    }
-
-    fn deinit(self: *Self) void {
-        self.allocator.free(self.buf);
-        self.* = undefined;
-    }
-
-    pub fn read(self: *const Self, comptime T: type, address: usize) T {
-        const addr = address & 0x3FF;
-
-        return switch (T) {
-            u32, u16, u8 => std.mem.readIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)]),
-            else => @compileError("OAM: Unsupported read width"),
-        };
-    }
-
-    pub fn write(self: *Self, comptime T: type, address: usize, value: T) void {
-        const addr = address & 0x3FF;
-
-        switch (T) {
-            u32, u16 => std.mem.writeIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)], value),
-            u8 => return, // 8-bit writes are explicitly ignored
-            else => @compileError("OAM: Unsupported write width"),
-        }
-    }
-};
-
 const Window = struct {
     const Self = @This();
 
@@ -1261,48 +1112,3 @@ const Scanline = struct {
         return self.layers[1];
     }
 };
-
-// Double Buffering Implementation
-const FrameBuffer = struct {
-    const Self = @This();
-
-    layers: [2][]u8,
-    buf: []u8,
-    current: u1,
-
-    allocator: Allocator,
-
-    // TODO: Rename
-    const Device = enum {
-        Emulator,
-        Renderer,
-    };
-
-    pub fn init(allocator: Allocator) !Self {
-        const framebuf_len = framebuf_pitch * height;
-        const buf = try allocator.alloc(u8, framebuf_len * 2);
-        std.mem.set(u8, buf, 0);
-
-        return .{
-            // Front and Back Framebuffers
-            .layers = [_][]u8{ buf[0..][0..framebuf_len], buf[framebuf_len..][0..framebuf_len] },
-            .buf = buf,
-            .current = 0,
-
-            .allocator = allocator,
-        };
-    }
-
-    fn deinit(self: *Self) void {
-        self.allocator.free(self.buf);
-        self.* = undefined;
-    }
-
-    pub fn swap(self: *Self) void {
-        self.current = ~self.current;
-    }
-
-    pub fn get(self: *Self, comptime dev: Device) []u8 {
-        return self.layers[if (dev == .Emulator) self.current else ~self.current];
-    }
-};

src/core/ppu/Oam.zig

@@ -0,0 +1,40 @@
+const std = @import("std");
+
+const Allocator = std.mem.Allocator;
+
+const buf_len = 0x400;
+const Self = @This();
+
+buf: []u8,
+allocator: Allocator,
+
+pub fn read(self: *const Self, comptime T: type, address: usize) T {
+    const addr = address & 0x3FF;
+
+    return switch (T) {
+        u32, u16, u8 => std.mem.readIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)]),
+        else => @compileError("OAM: Unsupported read width"),
+    };
+}
+
+pub fn write(self: *Self, comptime T: type, address: usize, value: T) void {
+    const addr = address & 0x3FF;
+
+    switch (T) {
+        u32, u16 => std.mem.writeIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)], value),
+        u8 => return, // 8-bit writes are explicitly ignored
+        else => @compileError("OAM: Unsupported write width"),
+    }
+}
+
+pub fn init(allocator: Allocator) !Self {
+    const buf = try allocator.alloc(u8, buf_len);
+    std.mem.set(u8, buf, 0);
+
+    return Self{ .buf = buf, .allocator = allocator };
+}
+
+pub fn deinit(self: *Self) void {
+    self.allocator.free(self.buf);
+    self.* = undefined;
+}

src/core/ppu/Palette.zig

@@ -0,0 +1,47 @@
+const std = @import("std");
+
+const Allocator = std.mem.Allocator;
+
+const buf_len = 0x400;
+const Self = @This();
+
+buf: []u8,
+allocator: Allocator,
+
+pub fn read(self: *const Self, comptime T: type, address: usize) T {
+    const addr = address & 0x3FF;
+
+    return switch (T) {
+        u32, u16, u8 => std.mem.readIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)]),
+        else => @compileError("PALRAM: Unsupported read width"),
+    };
+}
+
+pub fn write(self: *Self, comptime T: type, address: usize, value: T) void {
+    const addr = address & 0x3FF;
+
+    switch (T) {
+        u32, u16 => std.mem.writeIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)], value),
+        u8 => {
+            const align_addr = addr & ~@as(u32, 1); // Aligned to Halfword boundary
+            std.mem.writeIntSliceLittle(u16, self.buf[align_addr..][0..@sizeOf(u16)], @as(u16, value) * 0x101);
+        },
+        else => @compileError("PALRAM: Unsupported write width"),
+    }
+}
+
+pub fn init(allocator: Allocator) !Self {
+    const buf = try allocator.alloc(u8, buf_len);
+    std.mem.set(u8, buf, 0);
+
+    return Self{ .buf = buf, .allocator = allocator };
+}
+
+pub fn deinit(self: *Self) void {
+    self.allocator.free(self.buf);
+    self.* = undefined;
+}
+
+pub fn backdrop(self: *const Self) u16 {
+    return self.read(u16, 0);
+}

src/core/ppu/Vram.zig

@@ -0,0 +1,60 @@
+const std = @import("std");
+const io = @import("../bus/io.zig");
+
+const Allocator = std.mem.Allocator;
+
+const buf_len = 0x18000;
+const Self = @This();
+
+buf: []u8,
+allocator: Allocator,
+
+pub fn read(self: *const Self, comptime T: type, address: usize) T {
+    const addr = Self.mirror(address);
+
+    return switch (T) {
+        u32, u16, u8 => std.mem.readIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)]),
+        else => @compileError("VRAM: Unsupported read width"),
+    };
+}
+
+pub fn write(self: *Self, comptime T: type, dispcnt: io.DisplayControl, address: usize, value: T) void {
+    const mode: u3 = dispcnt.bg_mode.read();
+    const idx = Self.mirror(address);
+
+    switch (T) {
+        u32, u16 => std.mem.writeIntSliceLittle(T, self.buf[idx..][0..@sizeOf(T)], value),
+        u8 => {
+            // Ignore write if it falls within the boundaries of OBJ VRAM
+            switch (mode) {
+                0, 1, 2 => if (0x0001_0000 <= idx) return,
+                else => if (0x0001_4000 <= idx) return,
+            }
+
+            const align_idx = idx & ~@as(u32, 1); // Aligned to a halfword boundary
+            std.mem.writeIntSliceLittle(u16, self.buf[align_idx..][0..@sizeOf(u16)], @as(u16, value) * 0x101);
+        },
+        else => @compileError("VRAM: Unsupported write width"),
+    }
+}
+
+pub fn init(allocator: Allocator) !Self {
+    const buf = try allocator.alloc(u8, buf_len);
+    std.mem.set(u8, buf, 0);
+
+    return Self{ .buf = buf, .allocator = allocator };
+}
+
+pub fn deinit(self: *Self) void {
+    self.allocator.free(self.buf);
+    self.* = undefined;
+}
+
+fn mirror(address: usize) usize {
+    // Mirrored in steps of 128K (64K + 32K + 32K) (abcc)
+    const addr = address & 0x1FFFF;
+
+    // If the address is within 96K we don't do anything,
+    // otherwise we want to mirror the last 32K (addresses between 64K and 96K)
+    return if (addr < buf_len) addr else 0x10000 + (addr & 0x7FFF);
+}

src/util.zig

@@ -5,6 +5,8 @@ const config = @import("config.zig");
 const Log2Int = std.math.Log2Int;
 const Arm7tdmi = @import("core/cpu.zig").Arm7tdmi;
 
+const Allocator = std.mem.Allocator;
+
 // Sign-Extend value of type `T` to type `U`
 pub fn sext(comptime T: type, comptime U: type, value: T) T {
     // U must have less bits than T
@@ -165,6 +167,7 @@ pub const io = struct {
 
 pub const Logger = struct {
     const Self = @This();
+    const FmtArgTuple = std.meta.Tuple(&.{ u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32 });
 
     buf: std.io.BufferedWriter(4096 << 2, std.fs.File.Writer),
 
@@ -223,8 +226,6 @@ pub const Logger = struct {
     }
 };
 
-const FmtArgTuple = std.meta.Tuple(&.{ u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32, u32 });
-
 pub const audio = struct {
     const _io = @import("core/bus/io.zig");
 
@@ -302,3 +303,44 @@ fn HalfInt(comptime T: type) type {
 
     return std.meta.Int(type_info.Int.signedness, type_info.Int.bits >> 1);
 }
+
+/// Double Buffering Implementation
+pub const FrameBuffer = struct {
+    const Self = @This();
+
+    layers: [2][]u8,
+    buf: []u8,
+    current: u1,
+
+    allocator: Allocator,
+
+    // TODO: Rename
+    const Device = enum { Emulator, Renderer };
+
+    pub fn init(allocator: Allocator, comptime len: comptime_int) !Self {
+        const buf = try allocator.alloc(u8, len * 2);
+        std.mem.set(u8, buf, 0);
+
+        return .{
+            // Front and Back Framebuffers
+            .layers = [_][]u8{ buf[0..][0..len], buf[len..][0..len] },
+            .buf = buf,
+            .current = 0,
+
+            .allocator = allocator,
+        };
+    }
+
+    pub fn deinit(self: *Self) void {
+        self.allocator.free(self.buf);
+        self.* = undefined;
+    }
+
+    pub fn swap(self: *Self) void {
+        self.current = ~self.current;
+    }
+
+    pub fn get(self: *Self, comptime dev: Device) []u8 {
+        return self.layers[if (dev == .Emulator) self.current else ~self.current];
+    }
+};