chore: update for loop in RingBuffer impl

respond to build.zig changes in zig master

.gitmodules

@@ -13,9 +13,6 @@
 [submodule "lib/zig-toml"]
 	path = lib/zig-toml
 	url = https://github.com/aeronavery/zig-toml
-[submodule "lib/zba-gdbstub"]
-	path = lib/zba-gdbstub
-	url = https://git.musuka.dev/paoda/zba-gdbstub
 [submodule "lib/zgui"]
 	path = lib/zgui
 	url = https://git.musuka.dev/paoda/zgui

build.zig

@@ -2,7 +2,6 @@ const std = @import("std");
 const builtin = @import("builtin");
 
 const Sdk = @import("lib/SDL.zig/Sdk.zig");
-const gdbstub = @import("lib/zba-gdbstub/build.zig");
 const zgui = @import("lib/zgui/build.zig");
 const nfd = @import("lib/nfd-zig/build.zig");
 
@@ -44,8 +43,6 @@ pub fn build(b: *std.build.Builder) void {
     // OpenGL 3.3 Bindings
     exe.addAnonymousModule("gl", .{ .source_file = .{ .path = "lib/gl.zig" } });
 
-    // gdbstub
-    gdbstub.link(exe);
     // NativeFileDialog(ue) Bindings
     exe.linkLibrary(nfd.makeLib(b, target, optimize));
     exe.addModule("nfd", nfd.getModule(b));

lib/zba-gdbstub

@@ -1 +0,0 @@
-Subproject commit acb59994fcfb83d36efef47810a9dc791c6e542e

src/core/Bus.zig

@@ -198,6 +198,55 @@ fn fillReadTableExternal(self: *Self, addr: u32) ?*anyopaque {
     return &self.pak.buf[masked_addr];
 }
 
+pub fn dbgRead(self: *const Self, comptime T: type, unaligned_address: u32) T {
+    const bits = @typeInfo(std.math.IntFittingRange(0, page_size - 1)).Int.bits;
+    const page = unaligned_address >> bits;
+    const offset = unaligned_address & (page_size - 1);
+
+    // We're doing some serious out-of-bounds open-bus reads
+    if (page >= table_len) return self.openBus(T, unaligned_address);
+
+    if (self.read_table[page]) |some_ptr| {
+        // We have a pointer to a page, cast the pointer to it's underlying type
+        const Ptr = [*]const T;
+        const ptr = @ptrCast(Ptr, @alignCast(@alignOf(std.meta.Child(Ptr)), some_ptr));
+
+        // Note: We don't check array length, since we force align the
+        // lower bits of the address as the GBA would
+        return ptr[forceAlign(T, offset) / @sizeOf(T)];
+    }
+
+    return self.dbgSlowRead(T, unaligned_address);
+}
+
+fn dbgSlowRead(self: *const Self, comptime T: type, unaligned_address: u32) T {
+    const page = @truncate(u8, unaligned_address >> 24);
+    const address = forceAlign(T, unaligned_address);
+
+    return switch (page) {
+        // General Internal Memory
+        0x00 => blk: {
+            if (address < Bios.size)
+                break :blk self.bios.dbgRead(T, self.cpu.r[15], unaligned_address);
+
+            break :blk self.openBus(T, address);
+        },
+        0x02 => unreachable, // handled by fastmem
+        0x03 => unreachable, // handled by fastmem
+        0x04 => self.readIo(T, address),
+
+        // Internal Display Memory
+        0x05 => unreachable, // handled by fastmem
+        0x06 => unreachable, // handled by fastmem
+        0x07 => unreachable, // handled by fastmem
+
+        // External Memory (Game Pak)
+        0x08...0x0D => self.pak.dbgRead(T, address),
+        0x0E...0x0F => self.readBackup(T, unaligned_address),
+        else => self.openBus(T, address),
+    };
+}
+
 fn readIo(self: *const Self, comptime T: type, address: u32) T {
     return io.read(self, T, address) orelse self.openBus(T, address);
 }
@@ -287,27 +336,6 @@ pub fn read(self: *Self, comptime T: type, unaligned_address: u32) T {
     return self.slowRead(T, unaligned_address);
 }
 
-pub fn dbgRead(self: *const Self, comptime T: type, unaligned_address: u32) T {
-    const bits = @typeInfo(std.math.IntFittingRange(0, page_size - 1)).Int.bits;
-    const page = unaligned_address >> bits;
-    const offset = unaligned_address & (page_size - 1);
-
-    // We're doing some serious out-of-bounds open-bus reads
-    if (page >= table_len) return self.openBus(T, unaligned_address);
-
-    if (self.read_table[page]) |some_ptr| {
-        // We have a pointer to a page, cast the pointer to it's underlying type
-        const Ptr = [*]const T;
-        const ptr = @ptrCast(Ptr, @alignCast(@alignOf(std.meta.Child(Ptr)), some_ptr));
-
-        // Note: We don't check array length, since we force align the
-        // lower bits of the address as the GBA would
-        return ptr[forceAlign(T, offset) / @sizeOf(T)];
-    }
-
-    return self.dbgSlowRead(T, unaligned_address);
-}
-
 fn slowRead(self: *Self, comptime T: type, unaligned_address: u32) T {
     @setCold(true);
 
@@ -338,34 +366,6 @@ fn slowRead(self: *Self, comptime T: type, unaligned_address: u32) T {
     };
 }
 
-fn dbgSlowRead(self: *const Self, comptime T: type, unaligned_address: u32) T {
-    const page = @truncate(u8, unaligned_address >> 24);
-    const address = forceAlign(T, unaligned_address);
-
-    return switch (page) {
-        // General Internal Memory
-        0x00 => blk: {
-            if (address < Bios.size)
-                break :blk self.bios.dbgRead(T, self.cpu.r[15], unaligned_address);
-
-            break :blk self.openBus(T, address);
-        },
-        0x02 => unreachable, // handled by fastmem
-        0x03 => unreachable, // handled by fastmem
-        0x04 => self.readIo(T, address),
-
-        // Internal Display Memory
-        0x05 => unreachable, // handled by fastmem
-        0x06 => unreachable, // handled by fastmem
-        0x07 => unreachable, // handled by fastmem
-
-        // External Memory (Game Pak)
-        0x08...0x0D => self.pak.dbgRead(T, address),
-        0x0E...0x0F => self.readBackup(T, unaligned_address),
-        else => self.openBus(T, address),
-    };
-}
-
 fn readBackup(self: *const Self, comptime T: type, unaligned_address: u32) T {
     const value = self.pak.backup.read(unaligned_address);
 
@@ -406,31 +406,6 @@ pub fn write(self: *Self, comptime T: type, unaligned_address: u32, value: T) vo
     }
 }
 
-/// Mostly Identical to `Bus.write`, slowmeme is handled by `Bus.dbgSlowWrite`
-pub fn dbgWrite(self: *Self, comptime T: type, unaligned_address: u32, value: T) void {
-    const bits = @typeInfo(std.math.IntFittingRange(0, page_size - 1)).Int.bits;
-    const page = unaligned_address >> bits;
-    const offset = unaligned_address & (page_size - 1);
-
-    // We're doing some serious out-of-bounds open-bus writes, they do nothing though
-    if (page >= table_len) return;
-
-    if (self.write_tables[@boolToInt(T == u8)][page]) |some_ptr| {
-        // We have a pointer to a page, cast the pointer to it's underlying type
-        const Ptr = [*]T;
-        const ptr = @ptrCast(Ptr, @alignCast(@alignOf(std.meta.Child(Ptr)), some_ptr));
-
-        // Note: We don't check array length, since we force align the
-        // lower bits of the address as the GBA would
-        ptr[forceAlign(T, offset) / @sizeOf(T)] = value;
-    } else {
-        // we can return early if this is an 8-bit OAM write
-        if (T == u8 and @truncate(u8, unaligned_address >> 24) == 0x07) return;
-
-        self.dbgSlowWrite(T, unaligned_address, value);
-    }
-}
-
 fn slowWrite(self: *Self, comptime T: type, unaligned_address: u32, value: T) void {
     @setCold(true);
 
@@ -456,31 +431,6 @@ fn slowWrite(self: *Self, comptime T: type, unaligned_address: u32, value: T) vo
     }
 }
 
-fn dbgSlowWrite(self: *Self, comptime T: type, unaligned_address: u32, value: T) void {
-    @setCold(true);
-
-    const page = @truncate(u8, unaligned_address >> 24);
-    const address = forceAlign(T, unaligned_address);
-
-    switch (page) {
-        // General Internal Memory
-        0x00 => self.bios.write(T, address, value),
-        0x02 => unreachable, // completely handled by fastmem
-        0x03 => unreachable, // completely handled by fastmem
-        0x04 => return, // FIXME: Let debug writes mess with I/O
-
-        // Internal Display Memory
-        0x05 => self.ppu.palette.write(T, address, value),
-        0x06 => self.ppu.vram.write(T, self.ppu.dispcnt, address, value),
-        0x07 => unreachable, // completely handled by fastmem
-
-        // External Memory (Game Pak)
-        0x08...0x0D => return, // FIXME: Debug Write to Backup/GPIO w/out messing with state
-        0x0E...0x0F => return, // FIXME: Debug Write to Backup w/out messing with state
-        else => {},
-    }
-}
-
 inline fn rotateBy(comptime T: type, address: u32) u32 {
     return switch (T) {
         u32 => address & 3,

src/core/emu.zig

@@ -166,59 +166,3 @@ fn sleep(timer: *Timer, wake_time: u64) ?u64 {
 fn spinLoop(timer: *Timer, wake_time: u64) void {
     while (true) if (timer.read() > wake_time) break;
 }
-
-pub const EmuThing = struct {
-    const Self = @This();
-    const Interface = @import("gdbstub").Emulator;
-    const Allocator = std.mem.Allocator;
-
-    cpu: *Arm7tdmi,
-    scheduler: *Scheduler,
-
-    pub fn init(cpu: *Arm7tdmi, scheduler: *Scheduler) Self {
-        return .{ .cpu = cpu, .scheduler = scheduler };
-    }
-
-    pub fn interface(self: *Self, allocator: Allocator) Interface {
-        return Interface.init(allocator, self);
-    }
-
-    pub fn read(self: *const Self, addr: u32) u8 {
-        return self.cpu.bus.dbgRead(u8, addr);
-    }
-
-    pub fn write(self: *Self, addr: u32, value: u8) void {
-        self.cpu.bus.dbgWrite(u8, addr, value);
-    }
-
-    pub fn registers(self: *const Self) *[16]u32 {
-        return &self.cpu.r;
-    }
-
-    pub fn cpsr(self: *const Self) u32 {
-        return self.cpu.cpsr.raw;
-    }
-
-    pub fn step(self: *Self) void {
-        const cpu = self.cpu;
-        const sched = self.scheduler;
-
-        // Is true when we have executed one (1) instruction
-        var did_step: bool = false;
-
-        // TODO: How can I make it easier to keep this in lock-step with runFrame?
-        while (!did_step) {
-            if (!cpu.stepDmaTransfer()) {
-                if (cpu.isHalted()) {
-                    // Fast-forward to next Event
-                    sched.tick = sched.queue.peek().?.tick;
-                } else {
-                    cpu.step();
-                    did_step = true;
-                }
-            }
-
-            if (sched.tick >= sched.nextTimestamp()) sched.handleEvent(cpu);
-        }
-    }
-};

src/core/ppu.zig

@@ -986,7 +986,8 @@ pub const Ppu = struct {
             cpu.handleInterrupt();
         }
 
-        // If we're not also in VBlank, attempt to run any pending DMA Reqs
+        // See if HBlank DMA is present and not enabled
+
         if (!self.dispstat.vblank.read())
             dma.onBlanking(cpu.bus, .HBlank);
 

src/main.zig

@@ -4,17 +4,14 @@ const known_folders = @import("known_folders");
 const clap = @import("clap");
 
 const config = @import("config.zig");
-const emu = @import("core/emu.zig");
 
 const Gui = @import("platform.zig").Gui;
 const Bus = @import("core/Bus.zig");
 const Arm7tdmi = @import("core/cpu.zig").Arm7tdmi;
 const Scheduler = @import("core/scheduler.zig").Scheduler;
 const FilePaths = @import("util.zig").FilePaths;
-const FpsTracker = @import("util.zig").FpsTracker;
-const Allocator = std.mem.Allocator;
-const Atomic = std.atomic.Atomic;
 
+const Allocator = std.mem.Allocator;
 const log = std.log.scoped(.Cli);
 pub const log_level = if (builtin.mode != .Debug) .info else std.log.default_level;
 
@@ -23,7 +20,6 @@ const params = clap.parseParamsComptime(
     \\-h, --help            Display this help and exit.
     \\-s, --skip            Skip BIOS.
     \\-b, --bios <str>      Optional path to a GBA BIOS ROM.
-    \\ --gdb                Run ZBA from the context of a GDB Server
     \\<str>                 Path to the GBA GamePak ROM.
     \\
 );
@@ -93,46 +89,7 @@ pub fn main() void {
     var gui = Gui.init(allocator, bus.pak.title, &bus.apu) catch |e| exitln("failed to init gui: {}", .{e});
     defer gui.deinit();
 
-    var quit = Atomic(bool).init(false);
-
-    if (result.args.gdb) {
-        const Server = @import("gdbstub").Server;
-        const EmuThing = @import("core/emu.zig").EmuThing;
-
-        var wrapper = EmuThing.init(&cpu, &scheduler);
-        var emulator = wrapper.interface(allocator);
-        defer emulator.deinit();
-
-        log.info("Ready to connect", .{});
-
-        var server = Server.init(emulator) catch |e| exitln("failed to init gdb server: {}", .{e});
-        defer server.deinit(allocator);
-
-        log.info("Starting GDB Server Thread", .{});
-
-        const thread = std.Thread.spawn(.{}, Server.run, .{ &server, allocator, &quit }) catch |e| exitln("gdb server thread crashed: {}", .{e});
-        defer thread.join();
-
-        gui.run(.{
-            .cpu = &cpu,
-            .scheduler = &scheduler,
-            .quit = &quit,
-        }) catch |e| exitln("main thread panicked: {}", .{e});
-    } else {
-        var tracker = FpsTracker.init();
-        var pause = Atomic(bool).init(false);
-
-        const thread = std.Thread.spawn(.{}, emu.run, .{ &quit, &pause, &cpu, &scheduler, &tracker }) catch |e| exitln("emu thread panicked: {}", .{e});
-        defer thread.join();
-
-        gui.run(.{
-            .cpu = &cpu,
-            .scheduler = &scheduler,
-            .tracker = &tracker,
-            .quit = &quit,
-            .pause = &pause,
-        }) catch |e| exitln("main thread panicked: {}", .{e});
-    }
+    gui.run(&cpu, &scheduler) catch |e| exitln("failed to run gui thread: {}", .{e});
 }
 
 fn handleArguments(allocator: Allocator, data_path: []const u8, result: *const clap.Result(clap.Help, &params, clap.parsers.default)) !FilePaths {

src/platform.zig

@@ -307,13 +307,16 @@ pub const Gui = struct {
             _ = zgui.begin("Information", .{});
             defer zgui.end();
 
-            for (0..8) |i| {
-                zgui.text("R{}: 0x{X:0>8}", .{ i, cpu.r[i] });
+            {
+                var i: usize = 0;
+                while (i < 8) : (i += 1) {
+                    zgui.text("R{}: 0x{X:0>8}", .{ i, cpu.r[i] });
 
-                zgui.sameLine(.{});
+                    zgui.sameLine(.{});
 
-                const prefix = if (8 + i < 10) " " else "";
-                zgui.text("{s}R{}: 0x{X:0>8}", .{ prefix, 8 + i, cpu.r[8 + i] });
+                    const prefix = if (8 + i < 10) " " else "";
+                    zgui.text("{s}R{}: 0x{X:0>8}", .{ prefix, 8 + i, cpu.r[8 + i] });
+                }
             }
 
             zgui.separator();
@@ -412,25 +415,12 @@ pub const Gui = struct {
             }
         }
 
-        // {
-        //     zgui.showDemoWindow(null);
-        // }
+        {
+            zgui.showDemoWindow(null);
+        }
     }
 
-    const RunOptions = struct {
-        quit: *std.atomic.Atomic(bool),
-        pause: ?*std.atomic.Atomic(bool) = null,
-        tracker: ?*FpsTracker = null,
-        cpu: *Arm7tdmi,
-        scheduler: *Scheduler,
-    };
-
-    pub fn run(self: *Self, opt: RunOptions) !void {
-        const cpu = opt.cpu;
-        const tracker = opt.tracker;
-        const quit = opt.quit;
-        const pause = opt.pause;
-
+    pub fn run(self: *Self, cpu: *Arm7tdmi, scheduler: *Scheduler) !void {
         const obj_ids = Self.genBufferObjects();
         defer gl.deleteBuffers(3, @as(*const [3]c_uint, &obj_ids));
 
@@ -441,16 +431,20 @@ pub const Gui = struct {
         const fbo_id = try Self.genFrameBufObject(out_tex);
         defer gl.deleteFramebuffers(1, &fbo_id);
 
-        emu_loop: while (true) {
-            // `quit` from RunOptions may be modified by the GDBSTUB thread,
-            // so we want to recognize that it may change to `true` and exit the GUI thread
-            if (quit.load(.Monotonic)) break :emu_loop;
+        var tracker = FpsTracker.init();
+        var quit = std.atomic.Atomic(bool).init(false);
+        var pause = std.atomic.Atomic(bool).init(false);
 
-            // Outside of `SDL.SDL_QUIT` below, the DearImgui UI might signal that the program
-            // should exit, in which case we should also handle this
+        const thread = try std.Thread.spawn(.{}, emu.run, .{ &quit, &pause, cpu, scheduler, &tracker });
+        defer thread.join();
+        defer quit.store(true, .Monotonic); // Terminate Emulator Thread
+
+        emu_loop: while (true) {
+            var event: SDL.SDL_Event = undefined;
+
+            // Quit Signal from Dear Imgui
             if (self.state.should_quit) break :emu_loop;
 
-            var event: SDL.SDL_Event = undefined;
             while (SDL.SDL_PollEvent(&event) != 0) {
                 _ = zgui.backend.processEvent(&event);
 
@@ -500,17 +494,12 @@ pub const Gui = struct {
                 }
             }
 
-            // If `Gui.run` has been passed with a `pause` atomic, we should
-            // pause the emulation thread while we access the data there
+            // We Access non-atomic parts of the Emulator here
             {
-                // TODO: Is there a nicer way to express this?
-                if (pause) |val| val.store(true, .Monotonic);
-                defer if (pause) |val| val.store(false, .Monotonic);
+                pause.store(true, .Monotonic);
+                defer pause.store(false, .Monotonic);
 
-                // Add FPS count to the histogram
-                if (tracker) |t| {
-                    self.state.fps_hist.push(t.value()) catch {};
-                }
+                self.state.fps_hist.push(tracker.value()) catch {};
 
                 // Draw GBA Screen to Texture
                 {
@@ -535,8 +524,6 @@ pub const Gui = struct {
 
             SDL.SDL_GL_SwapWindow(self.window);
         }
-
-        quit.store(true, .Monotonic); // Signals to emu thread to exit
     }
 
     fn glGetProcAddress(ctx: SDL.SDL_GLContext, proc: [:0]const u8) ?*anyopaque {