fixes for zig 0.12 (except AVR)

Author: 190n

.gitignore

@@ -1,2 +1,3 @@
 zig-cache
 zig-out
+.vscode

build.zig

@@ -13,7 +13,9 @@ pub fn build(b: *std.Build) void {
     // Standard optimization options allow the person running `zig build` to select
     // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
     // set a preferred release mode, allowing the user to decide how to optimize.
-    const optimize = b.standardOptimizeOption(.{});
+    const optimize = b.standardOptimizeOption(.{
+        .preferred_optimize_mode = .ReleaseSmall,
+    });
 
     const use_avr_gcc = b.option(
         bool,
@@ -44,23 +46,27 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
     });
-    native_library.addModule("build_options", options_module);
-    const native_library_install = b.addInstallLibFile(native_library.getEmittedBin(), "libzip8.a");
+    native_library.root_module.addImport("build_options", options_module);
+    const native_library_install = b.addInstallLibFile(
+        native_library.getEmittedBin(),
+        b.fmt("libzip8{s}", .{target.result.dynamicLibSuffix()}),
+    );
 
-    const wasm_library = b.addSharedLibrary(.{
+    const wasm_library = b.addExecutable(.{
         .name = "zip8",
         // In this case the main source file is merely a path, however, in more
         // complicated build scripts, this could be a generated file.
         .root_source_file = .{ .path = "src/main.zig" },
-        .target = .{
+        .target = b.resolveTargetQuery(.{
             .cpu_arch = .wasm32,
             .os_tag = .freestanding,
             .cpu_features_add = std.Target.wasm.featureSet(&.{.bulk_memory}),
-        },
+        }),
         .optimize = optimize,
     });
+    wasm_library.entry = .disabled;
+    wasm_library.root_module.addImport("build_options", options_module);
     wasm_library.rdynamic = true;
-    wasm_library.addModule("build_options", options_module);
 
     const wasm_step = b.step("wasm", "Build WebAssembly library");
 
@@ -91,49 +97,46 @@ pub fn build(b: *std.Build) void {
         // In this case the main source file is merely a path, however, in more
         // complicated build scripts, this could be a generated file.
         .root_source_file = .{ .path = "src/main.zig" },
-        .target = .{
+        .target = b.resolveTargetQuery(.{
             .cpu_arch = .thumb,
             .os_tag = .freestanding,
             .abi = .eabi,
             .cpu_model = .{ .explicit = &std.Target.arm.cpu.cortex_m0plus },
-        },
+        }),
         .optimize = optimize,
     });
-    m0plus_library.addModule("build_options", options_module);
+    m0plus_library.root_module.addImport("build_options", options_module);
     const m0plus_library_install = b.addInstallLibFile(m0plus_library.getEmittedBin(), "cortex-m0plus/libzip8.a");
 
     // build a static library for AVR
     const atmega4809_library = b.addStaticLibrary(.{
         .name = "zip8",
         .root_source_file = .{ .path = "src/main.zig" },
-        .target = .{
+        .target = b.resolveTargetQuery(.{
             .cpu_arch = .avr,
             .os_tag = .freestanding,
             .cpu_model = .{ .explicit = &std.Target.avr.cpu.atmega4809 },
             .ofmt = if (use_avr_gcc) .c else null,
-        },
+        }),
         .optimize = optimize,
     });
-    atmega4809_library.addModule("build_options", options_module);
+    atmega4809_library.root_module.addImport("build_options", options_module);
 
     const atmega4809_library_file = if (use_avr_gcc) bin: {
-        // we use this to get the lib_dir from our zig installation as that directory contains zig.h
-        const zig_lib_dir_cmd = b.addSystemCommand(&.{ "sh", "-c", "$0 env | jq -r .lib_dir", b.zig_exe });
-        const zig_lib_dir_file = zig_lib_dir_cmd.captureStdOut();
-
         const gcc_cmd = b.addSystemCommand(&.{
             "sh",
             "-c",
-            "avr-gcc -c -Wno-incompatible-pointer-types -Wno-builtin-declaration-mismatch -mmcu=atmega4809 $0 -I $(cat $1) $2 -o $3",
+            "avr-gcc -c -Wno-incompatible-pointer-types -Wno-builtin-declaration-mismatch -mmcu=atmega4809 $0 -I $1 $2 -o $3",
             switch (optimize) {
                 .Debug => "-g",
                 .ReleaseSafe => "-O3",
                 .ReleaseFast => "-O3",
                 .ReleaseSmall => "-Oz",
             },
         });
-        gcc_cmd.addFileArg(zig_lib_dir_file);
+        gcc_cmd.addArg(b.lib_dir);
         gcc_cmd.addFileArg(atmega4809_library.getEmittedBin());
+
         const avr_object_path = gcc_cmd.addOutputFileArg("zip8.o");
 
         const ar_cmd = b.addSystemCommand(&.{ "ar", "-rcs" });
@@ -150,8 +153,8 @@ pub fn build(b: *std.Build) void {
     const write_files_step = b.addWriteFiles();
     _ = write_files_step.addCopyFile(m0plus_library.getEmittedBin(), "zip8/src/cortex-m0plus/libzip8.a");
     _ = write_files_step.addCopyFile(atmega4809_library_file, "zip8/src/atmega4809/libzip8.a");
-    _ = write_files_step.addCopyFile(std.build.LazyPath.relative("src/zip8.h"), "zip8/src/zip8.h");
-    _ = write_files_step.addCopyFile(std.build.LazyPath.relative("library.properties"), "zip8/library.properties");
+    _ = write_files_step.addCopyFile(b.path("src/zip8.h"), "zip8/src/zip8.h");
+    _ = write_files_step.addCopyFile(b.path("library.properties"), "zip8/library.properties");
     const zip_step = b.addSystemCommand(&.{ "sh", "-c", "cd $0; zip -r $1 zip8" });
     zip_step.addDirectoryArg(write_files_step.getDirectory());
     const zip_output = zip_step.addOutputFileArg("zip8.zip");
@@ -174,12 +177,12 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
     });
-    exe_tests.addModule("build_options", options_module);
+    exe_tests.root_module.addImport("build_options", options_module);
 
     // Similar to creating the run step earlier, this exposes a `test` step to
     // the `zig build --help` menu, providing a way for the user to request
     // running the unit tests.
     const test_step = b.step("test", "Run unit tests");
-    const test_run_cmd = b.addRunArtifact(exe_tests.step.cast(std.build.Step.Compile).?);
+    const test_run_cmd = b.addRunArtifact(exe_tests.step.cast(std.Build.Step.Compile).?);
     test_step.dependOn(&test_run_cmd.step);
 }

src/bindings.zig

@@ -107,18 +107,28 @@ export fn zip8CpuSetFlagsNotDirty(cpu: ?*anyopaque) callconv(.C) void {
     cpuPtrCast(cpu).flags_dirty = false;
 }
 
-fn zip8CpuAlloc() callconv(.C) ?[*]u8 {
-    return (std.heap.wasm_allocator.alignedAlloc(u8, @alignOf(Cpu), @sizeOf(Cpu)) catch return null).ptr;
+export fn zip8CpuGetDrawBytes(cpu: ?*const anyopaque) callconv(.C) usize {
+    return cpuPtrCast(cpu).draw_bytes_this_frame;
 }
 
-fn wasmAlloc(n: usize) callconv(.C) ?[*]u8 {
-    return (std.heap.wasm_allocator.alignedAlloc(u8, @import("builtin").target.maxIntAlignment(), n) catch return null).ptr;
+export fn zip8CpuResetDrawBytes(cpu: ?*anyopaque) callconv(.C) void {
+    cpuPtrCast(cpu).draw_bytes_this_frame = 0;
 }
 
 comptime {
     if (@import("builtin").target.isWasm()) {
-        @export(zip8CpuAlloc, .{ .name = "zip8CpuAlloc" });
-        @export(wasmAlloc, .{ .name = "wasmAlloc" });
+        const wasm_only_functions = struct {
+            fn zip8CpuAlloc() callconv(.C) ?[*]u8 {
+                return (std.heap.wasm_allocator.alignedAlloc(u8, @alignOf(Cpu), @sizeOf(Cpu)) catch return null).ptr;
+            }
+
+            fn wasmAlloc(n: usize) callconv(.C) ?[*]u8 {
+                return (std.heap.wasm_allocator.alignedAlloc(u8, @import("builtin").target.maxIntAlignment(), n) catch return null).ptr;
+            }
+        };
+
+        @export(wasm_only_functions.zip8CpuAlloc, .{ .name = "zip8CpuAlloc" });
+        @export(wasm_only_functions.wasmAlloc, .{ .name = "wasmAlloc" });
     }
 }
 

src/cpu.zig

@@ -36,15 +36,20 @@ const log = if (@import("builtin").is_test) struct {
 V: [16]u8 = .{0} ** 16,
 /// 12-bit register I for indexing memory
 I: u12 = 0,
-/// 4 KiB of memory
-mem: [memory_size]u8 = [_]u8{0} ** memory_size,
 /// program counter
 pc: u12 = initial_pc,
 /// call stack
 stack: std.BoundedArray(u12, 16),
 /// random number generator to use
 rand: std.rand.DefaultPrng,
 
+/// 4 KiB of memory
+mem: [memory_size]u8 = .{0x00} ** memory_size,
+/// track which memory has not been synchronized to clients
+mem_dirty: [memory_size / 8]u8 = .{0xff} ** (memory_size / 8),
+
+draw_bytes_this_frame: usize = 0,
+
 /// display is 64x32 stored row-major
 display: [display_width * display_height / 8]u8 = .{0} ** (display_width * display_height / 8),
 /// whether the contents of the screen have changed since the last time this flag was set to false

src/instruction.zig

@@ -23,6 +23,8 @@ opcode: u16,
 
 const testing_seed = 1337;
 
+const draw_log = std.log.scoped(.draw);
+
 /// split up an opcode into useful parts
 pub fn decode(opcode: u16) Instruction {
     const nibbles = [4]u4{
@@ -113,6 +115,8 @@ fn op00EX(self: Instruction, cpu: *Cpu) !?u12 {
         0x00E0 => {
             @memset(&cpu.display, 0);
             cpu.display_dirty = true;
+            draw_log.info("clear", .{});
+            cpu.draw_bytes_this_frame += 4;
             return null;
         },
         0x00EE => {
@@ -639,20 +643,16 @@ test "CXNN random" {
     try std.testing.expectEqual(@as(u8, 0x00), cpu.V[0x0]);
 }
 
-export fn draw(ptr: ?*anyopaque, xReg: u8, yReg: u8, rows: u8) callconv(.C) void {
-    const cpu: *Cpu = @alignCast(@ptrCast(ptr.?));
-    const inst = Instruction.decode(0xd000 | (@as(u16, xReg) << 8) | (yReg << 4) | rows);
-    _ = inst.exec(cpu) catch unreachable;
-    cpu.pc +%= 2;
-}
-
 /// DXYN: draw an 8xN sprite from memory starting at I at (VX, VY); set VF to 1 if any pixel was
 /// turned off, 0 otherwise
 fn opDraw(self: Instruction, cpu: *Cpu) !?u12 {
     cpu.V[0xF] = 0;
-    const sprite: []const u8 = cpu.mem[(cpu.I)..(cpu.I + self.low4)];
+    const sprite: []const u8 = cpu.mem[cpu.I..][0..self.low4];
     const x_start = cpu.V[self.regX] % Cpu.display_width;
     const y_start = cpu.V[self.regY] % Cpu.display_height;
+
+    var any_bytes_dirty = false;
+
     for (sprite, 0..) |row, y_sprite| {
         for (0..8) |x_sprite| {
             const pixel: u1 = @truncate(row >> @intCast(7 - x_sprite));
@@ -668,8 +668,21 @@ fn opDraw(self: Instruction, cpu: *Cpu) !?u12 {
                 cpu.invertPixel(x, y);
                 cpu.display_dirty = true;
             }
+
+            const mem_index = y_sprite + cpu.I;
+            if ((cpu.mem_dirty[mem_index / 8] >> @truncate(mem_index)) & 0x01 != 0) {
+                any_bytes_dirty = true;
+                cpu.mem_dirty[mem_index / 8] ^= (@as(u8, 1) << @truncate(mem_index));
+            }
         }
     }
+
+    if (any_bytes_dirty) {
+        draw_log.info("untaint: [{}, {})", .{ cpu.I, cpu.I + self.low4 });
+        cpu.draw_bytes_this_frame += self.low4;
+    }
+    draw_log.info("sprite: {} rows at ({}, {})", .{ sprite.len, x_start, y_start });
+    cpu.draw_bytes_this_frame += 4;
     return null;
 }
 
@@ -934,6 +947,7 @@ fn opStore(self: Instruction, cpu: *Cpu) !?u12 {
     for (0..(@as(u8, self.regX) + 1)) |offset| {
         cpu.mem[cpu.I] = cpu.V[offset];
         cpu.I +%= 1;
+        cpu.mem_dirty[cpu.I / 8] |= (@as(u8, 1) << @truncate(cpu.I));
     }
     return null;
 }

src/main.zig

@@ -10,25 +10,26 @@ pub fn panic(msg: []const u8, error_return_trace: ?*std.builtin.StackTrace, ret_
     while (true) {}
 }
 
-pub const std_options = struct {
-    pub const log_level = .info;
+pub fn logFn(
+    comptime level: std.log.Level,
+    comptime scope: @Type(.EnumLiteral),
+    comptime format: []const u8,
+    args: anytype,
+) void {
+    const level_prefix = comptime level.asText();
+    const prefix = comptime level_prefix ++ switch (scope) {
+        .default => ": ",
+        else => " (" ++ @tagName(scope) ++ "): ",
+    };
 
-    pub fn logFn(
-        comptime level: std.log.Level,
-        comptime scope: @TypeOf(.EnumLiteral),
-        comptime format: []const u8,
-        args: anytype,
-    ) void {
-        const level_prefix = comptime level.asText();
-        const prefix = comptime level_prefix ++ switch (scope) {
-            .default => ": ",
-            else => " (" ++ @tagName(scope) ++ "): ",
-        };
+    var buf: [1024:0]u8 = undefined;
+    const string = std.fmt.bufPrintZ(&buf, prefix ++ format, args) catch &buf;
+    zip8Log(string.ptr, string.len);
+}
 
-        var buf: [1024:0]u8 = undefined;
-        const string = std.fmt.bufPrintZ(&buf, prefix ++ format, args) catch &buf;
-        zip8Log(string.ptr, string.len);
-    }
+pub const std_options = std.Options{
+    .log_level = .info,
+    .logFn = logFn,
 };
 
 comptime {

web-host/src/cpu.ts

@@ -31,6 +31,8 @@ interface Zip8Exports {
 	zip8CpuFlagsAreDirty(cpuPtr: number): boolean;
 	zip8CpuSetFlagsNotDirty(cpuPtr: number): void;
 	zip8CpuAlloc(): number;
+	zip8CpuGetDrawBytes(cpuPtr: number): number;
+	zip8CpuResetDrawBytes(cpuPtr: number): void;
 	wasmAlloc(size: number): number;
 }
 
@@ -202,4 +204,12 @@ export default class CPU {
 		}
 		return flags;
 	}
+
+	getDrawBytes(): number {
+		return this.exports.zip8CpuGetDrawBytes(this.cpuPtr);
+	}
+
+	resetDrawBytes() {
+		this.exports.zip8CpuResetDrawBytes(this.cpuPtr);
+	}
 }

web-host/src/main.ts

@@ -92,6 +92,8 @@ async function run(rom: ArrayBuffer) {
 			cpu.setKeys(keys);
 		}
 
+		cpu.resetDrawBytes();
+
 		if (!cpu.isWaitingForKey()) {
 			for (let i = 0; i < instructionsPerTick && !halt; i++) {
 				try {
@@ -116,6 +118,8 @@ async function run(rom: ArrayBuffer) {
 				localStorage.setItem(key, JSON.stringify(flags));
 			}
 		}
+
+		console.log(cpu.getDrawBytes());
 	}
 
 	tick();