chore: introduce zba-util

In an effort to reuse code between zba and zba-gdbstub, move common util
code (like the SPSC Channel I implemented in this commit) in a new lib

.gitmodules

@@ -22,3 +22,6 @@
 [submodule "lib/nfd-zig"]
 	path = lib/nfd-zig
 	url = https://github.com/fabioarnold/nfd-zig
+[submodule "lib/zba-util"]
+	path = lib/zba-util
+	url = https://git.musuka.dev/paoda/zba-util.git

build.zig

@@ -33,7 +33,7 @@ pub fn build(b: *std.build.Builder) void {
     exe.addAnonymousModule("datetime", .{ .source_file = .{ .path = "lib/zig-datetime/src/main.zig" } });
 
     // Bitfield type from FlorenceOS: https://github.com/FlorenceOS/
-    exe.addAnonymousModule("bitfield", .{ .source_file = .{ .path = "lib/util/bitfield.zig" } });
+    exe.addAnonymousModule("bitfield", .{ .source_file = .{ .path = "lib/bitfield.zig" } });
 
     // Argument Parsing Library
     exe.addAnonymousModule("clap", .{ .source_file = .{ .path = "lib/zig-clap/clap.zig" } });
@@ -44,6 +44,9 @@ pub fn build(b: *std.build.Builder) void {
     // OpenGL 3.3 Bindings
     exe.addAnonymousModule("gl", .{ .source_file = .{ .path = "lib/gl.zig" } });
 
+    // ZBA utility code
+    exe.addAnonymousModule("zba-util", .{ .source_file = .{ .path = "lib/zba-util/src/lib.zig" } });
+
     // gdbstub
     gdbstub.link(exe);
     // NativeFileDialog(ue) Bindings

lib/zba-util

@@ -0,0 +1 @@
+Subproject commit 52ac8d952fe7c722e33a3237e465dcf258076613

src/core/Bus.zig

@@ -19,7 +19,7 @@ const log = std.log.scoped(.Bus);
 
 const createDmaTuple = @import("bus/dma.zig").create;
 const createTimerTuple = @import("bus/timer.zig").create;
-const rotr = @import("../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
 
 const timings: [2][0x10]u8 = [_][0x10]u8{
     // BIOS, Unused, EWRAM, IWRAM, I/0, PALRAM, VRAM, OAM, ROM0, ROM0, ROM1, ROM1, ROM2, ROM2, SRAM, Unused

src/core/apu.zig

@@ -14,7 +14,6 @@ const SoundFifo = std.fifo.LinearFifo(u8, .{ .Static = 0x20 });
 
 const getHalf = util.getHalf;
 const setHalf = util.setHalf;
-const intToBytes = util.intToBytes;
 
 const log = std.log.scoped(.APU);
 
@@ -557,7 +556,7 @@ pub fn DmaSound(comptime kind: DmaSoundKind) type {
         pub fn push(self: *Self, value: u32) void {
             if (!self.enabled) self.enable();
 
-            self.fifo.write(&intToBytes(u32, value)) catch |e| log.err("{} Error: {}", .{ kind, e });
+            self.fifo.write(std.mem.asBytes(&value)) catch |e| log.err("{} Error: {}", .{ kind, e });
         }
 
         fn enable(self: *Self) void {

src/core/bus/Bios.zig

@@ -3,7 +3,7 @@ const std = @import("std");
 const Allocator = std.mem.Allocator;
 const log = std.log.scoped(.Bios);
 
-const rotr = @import("../../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
 const forceAlign = @import("../Bus.zig").forceAlign;
 
 /// Size of the BIOS in bytes

src/core/bus/dma.zig

@@ -12,7 +12,7 @@ const getHalf = util.getHalf;
 const setHalf = util.setHalf;
 const setQuart = util.setQuart;
 
-const rotr = @import("../../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
 
 pub fn create() DmaTuple {
     return .{ DmaController(0).init(), DmaController(1).init(), DmaController(2).init(), DmaController(3).init() };

src/core/cpu/arm/branch.zig

@@ -2,7 +2,7 @@ const Bus = @import("../../Bus.zig");
 const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
 const InstrFn = @import("../../cpu.zig").arm.InstrFn;
 
-const sext = @import("../../../util.zig").sext;
+const sext = @import("zba-util").sext;
 
 pub fn branch(comptime L: bool) InstrFn {
     return struct {

src/core/cpu/arm/half_signed_data_transfer.zig

@@ -2,8 +2,8 @@ const Bus = @import("../../Bus.zig");
 const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
 const InstrFn = @import("../../cpu.zig").arm.InstrFn;
 
-const sext = @import("../../../util.zig").sext;
+const sext = @import("zba-util").sext;
-const rotr = @import("../../../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
 
 pub fn halfAndSignedDataTransfer(comptime P: bool, comptime U: bool, comptime I: bool, comptime W: bool, comptime L: bool) InstrFn {
     return struct {

src/core/cpu/arm/psr_transfer.zig

@@ -7,7 +7,7 @@ const PSR = @import("../../cpu.zig").PSR;
 
 const log = std.log.scoped(.PsrTransfer);
 
-const rotr = @import("../../../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
 
 pub fn psrTransfer(comptime I: bool, comptime R: bool, comptime kind: u2) InstrFn {
     return struct {

src/core/cpu/arm/single_data_swap.zig

@@ -2,7 +2,7 @@ const Bus = @import("../../Bus.zig");
 const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
 const InstrFn = @import("../../cpu.zig").arm.InstrFn;
 
-const rotr = @import("../../../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
 
 pub fn singleDataSwap(comptime B: bool) InstrFn {
     return struct {

src/core/cpu/arm/single_data_transfer.zig

@@ -3,7 +3,7 @@ const Bus = @import("../../Bus.zig");
 const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
 const InstrFn = @import("../../cpu.zig").arm.InstrFn;
 
-const rotr = @import("../../../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
 
 pub fn singleDataTransfer(comptime I: bool, comptime P: bool, comptime U: bool, comptime B: bool, comptime W: bool, comptime L: bool) InstrFn {
     return struct {

src/core/cpu/barrel_shifter.zig

@@ -1,7 +1,7 @@
 const Arm7tdmi = @import("../cpu.zig").Arm7tdmi;
 const CPSR = @import("../cpu.zig").PSR;
 
-const rotr = @import("../../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
 
 pub fn exec(comptime S: bool, cpu: *Arm7tdmi, opcode: u32) u32 {
     var result: u32 = undefined;

src/core/cpu/thumb/branch.zig

@@ -3,7 +3,7 @@ const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
 const InstrFn = @import("../../cpu.zig").thumb.InstrFn;
 
 const checkCond = @import("../../cpu.zig").checkCond;
-const sext = @import("../../../util.zig").sext;
+const sext = @import("zba-util").sext;
 
 pub fn fmt16(comptime cond: u4) InstrFn {
     return struct {

src/core/cpu/thumb/data_transfer.zig

@@ -2,8 +2,8 @@ const Bus = @import("../../Bus.zig");
 const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
 const InstrFn = @import("../../cpu.zig").thumb.InstrFn;
 
-const rotr = @import("../../../util.zig").rotr;
+const rotr = @import("zba-util").rotr;
-const sext = @import("../../../util.zig").sext;
+const sext = @import("zba-util").sext;
 
 pub fn fmt6(comptime rd: u3) InstrFn {
     return struct {

src/imgui.zig

@@ -11,7 +11,7 @@ const emu = @import("core/emu.zig");
 
 const Gui = @import("platform.zig").Gui;
 const Arm7tdmi = @import("core/cpu.zig").Arm7tdmi;
-const RingBuffer = @import("util.zig").RingBuffer;
+const RingBuffer = @import("zba-util").RingBuffer;
 
 const Allocator = std.mem.Allocator;
 const GLuint = gl.GLuint;
@@ -43,7 +43,7 @@ pub const State = struct {
 
     pub fn deinit(self: *@This(), allocator: Allocator) void {
         allocator.free(self.title);
-        self.fps_hist.deinit(allocator);
+        allocator.free(self.fps_hist.buf);
 
         self.* = undefined;
     }

src/main.zig

@@ -70,9 +70,10 @@ pub fn main() void {
     const paths = handleArguments(allocator, data_path, &result) catch |e| exitln("failed to handle cli arguments: {}", .{e});
     defer if (paths.save) |path| allocator.free(path);
 
-    const log_file = if (config.config().debug.cpu_trace) blk: {
+    const log_file = switch (config.config().debug.cpu_trace) {
-        break :blk std.fs.cwd().createFile("zba.log", .{}) catch |e| exitln("failed to create trace log file: {}", .{e});
+        true => std.fs.cwd().createFile("zba.log", .{}) catch |e| exitln("failed to create trace log file: {}", .{e}),
-    } else null;
+        false => null,
+    };
     defer if (log_file) |file| file.close();
 
     // TODO: Take Emulator Init Code out of main.zig

src/util.zig

@@ -7,27 +7,6 @@ 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
-    comptime std.debug.assert(@typeInfo(U).Int.bits <= @typeInfo(T).Int.bits);
-
-    const iT = std.meta.Int(.signed, @typeInfo(T).Int.bits);
-    const ExtU = if (@typeInfo(U).Int.signedness == .unsigned) T else iT;
-    const shift_amt = @intCast(Log2Int(T), @typeInfo(T).Int.bits - @typeInfo(U).Int.bits);
-
-    return @bitCast(T, @bitCast(iT, @as(ExtU, @truncate(U, value)) << shift_amt) >> shift_amt);
-}
-
-/// See https://godbolt.org/z/W3en9Eche
-pub inline fn rotr(comptime T: type, x: T, r: anytype) T {
-    if (@typeInfo(T).Int.signedness == .signed)
-        @compileError("cannot rotate signed integer");
-
-    const ar = @intCast(Log2Int(T), @mod(r, @typeInfo(T).Int.bits));
-    return x >> ar | x << (1 +% ~ar);
-}
-
 pub const FpsTracker = struct {
     const Self = @This();
 
@@ -57,17 +36,6 @@ pub const FpsTracker = struct {
     }
 };
 
-pub fn intToBytes(comptime T: type, value: anytype) [@sizeOf(T)]u8 {
-    comptime std.debug.assert(@typeInfo(T) == .Int);
-
-    var result: [@sizeOf(T)]u8 = undefined;
-
-    var i: Log2Int(T) = 0;
-    while (i < result.len) : (i += 1) result[i] = @truncate(u8, value >> i * @bitSizeOf(u8));
-
-    return result;
-}
-
 /// Creates a copy of a title with all Filesystem-invalid characters replaced
 ///
 /// e.g. POKEPIN R/S to POKEPIN R_S
@@ -317,78 +285,3 @@ pub const FrameBuffer = struct {
         return self.layers[if (dev == .Emulator) self.current else ~self.current];
     }
 };
-
-pub fn RingBuffer(comptime T: type) type {
-    return struct {
-        const Self = @This();
-        const Index = usize;
-        const max_capacity = (@as(Index, 1) << @typeInfo(Index).Int.bits - 1) - 1; // half the range of index type
-
-        const log = std.log.scoped(.RingBuffer);
-
-        read: Index,
-        write: Index,
-        buf: []T,
-
-        const Error = error{buffer_full};
-
-        pub fn init(buf: []T) Self {
-            std.debug.assert(std.math.isPowerOfTwo(buf.len)); // capacity must be a power of two
-            std.debug.assert(buf.len <= max_capacity);
-
-            std.mem.set(T, buf, 0);
-
-            return .{ .read = 0, .write = 0, .buf = buf };
-        }
-
-        pub fn deinit(self: *Self, allocator: Allocator) void {
-            allocator.free(self.buf);
-            self.* = undefined;
-        }
-
-        pub fn push(self: *Self, value: T) Error!void {
-            if (self.isFull()) return error.buffer_full;
-            defer self.write += 1;
-
-            self.buf[self.mask(self.write)] = value;
-        }
-
-        pub fn pop(self: *Self) ?T {
-            if (self.isEmpty()) return null;
-            defer self.read += 1;
-
-            return self.buf[self.mask(self.read)];
-        }
-
-        /// Returns the number of entries read
-        pub fn copy(self: *const Self, cpy: []T) Index {
-            const count = std.math.min(self.len(), cpy.len);
-            var start: Index = self.read;
-
-            for (cpy, 0..) |*v, i| {
-                if (i >= count) break;
-
-                v.* = self.buf[self.mask(start)];
-                start += 1;
-            }
-
-            return count;
-        }
-
-        fn len(self: *const Self) Index {
-            return self.write - self.read;
-        }
-
-        fn isFull(self: *const Self) bool {
-            return self.len() == self.buf.len;
-        }
-
-        fn isEmpty(self: *const Self) bool {
-            return self.read == self.write;
-        }
-
-        fn mask(self: *const Self, idx: Index) Index {
-            return idx & (self.buf.len - 1);
-        }
-    };
-}