Add console tetris demo

apps/zigtris/src/console.zig

@@ -0,0 +1,49 @@
+const std = @import("std");
+extern fn console_write(data: [*]const u8, len: usize) void;
+var wbuf:[4096]u8 = undefined;
+var cw = ConsoleWriter.init(&wbuf);
+const uvm = @import("uvm.zig");
+
+pub const WriteError = error{ Unsupported, NotConnected };
+
+pub const ConsoleWriter = struct {
+    interface: std.Io.Writer,
+    err: ?WriteError = null,
+
+    fn drain(w: *std.Io.Writer, data: []const []const u8, splat: usize) std.Io.Writer.Error!usize {
+        var ret: usize = 0;
+
+        const b = w.buffered();
+        uvm.print(b);
+        _ = w.consume(b.len);
+
+        for (data) |d| {
+            uvm.print(d);
+            ret += d.len;
+        }
+
+        const pattern = data[data.len - 1];
+        for (0..splat) |_| {
+            uvm.print(pattern);
+            ret += pattern.len;
+        }
+
+        return ret;
+    }
+
+    pub fn init(buf: []u8) ConsoleWriter {
+        return ConsoleWriter{
+            .interface = .{
+                .buffer = buf,
+                .vtable = &.{
+                    .drain = drain,
+                },
+            },
+        };
+    }
+};
+
+pub fn getWriter() *std.Io.Writer {
+    return &cw.interface;
+}
+

apps/zigtris/src/main.zig

@@ -0,0 +1,41 @@
+const uvm = @import("uvm.zig");
+
+const mibu = @import("mibu");
+const zigtris = @import("zigtris");
+var nextEvent:mibu.events.Event = .none;
+
+const console = @import("console.zig").getWriter();
+
+export fn main() void {
+    var gameRunning = true;
+    var lastUpdate:u32 = 0;
+
+    zigtris.gamesetup(console, uvm.millis()) catch |err| {
+        _ = console.print("err {any}\n", .{err}) catch 0;
+        _ = console.flush() catch 0;
+        return;
+    };
+
+    while(gameRunning) {
+        const now = uvm.millis();
+        if (uvm.getch()) |key| {
+            switch(key) {
+                ' ' => nextEvent = mibu.events.Event{.key = .{.code = .{.char = ' '}}},
+                'a' => nextEvent = mibu.events.Event{.key = .{.code = .left}},
+                'd' => nextEvent = mibu.events.Event{.key = .{.code = .right}},
+                'w' => nextEvent = mibu.events.Event{.key = .{.code = .up}},
+                's' => nextEvent = mibu.events.Event{.key = .{.code = .down}},
+                'q' => gameRunning = false,
+                else => {},
+            }
+        }
+
+        if (now > lastUpdate + 100 or nextEvent != .none) {
+
+            lastUpdate = now;
+            gameRunning = zigtris.gameloop(console, now, nextEvent) catch false;
+            nextEvent = .none;
+            _ = console.flush() catch 0;
+        }
+    }
+}

apps/zigtris/src/uvm.zig

@@ -0,0 +1,73 @@
+const uvm32 = @cImport({
+    @cDefine("USE_MAIN", "1");
+    @cInclude("uvm32_target.h");
+});
+const std = @import("std");
+
+// dupeZ would be better, but want to avoid using an allocator
+var new_buf:[128]u8 = undefined;
+pub inline fn print(m: []const u8) void {
+    @memcpy(new_buf[0..m.len], m);
+    new_buf[m.len] = 0;
+    const s = new_buf[0..m.len :0];
+
+    asm volatile ("csrw " ++ std.fmt.comptimePrint("0x{x}", .{uvm32.IOREQ_PRINT}) ++ ", %[arg1]"
+        :
+        : [arg1] "r" (s.ptr),
+    );
+}
+
+pub inline fn println(val: [:0]const u8) void {
+    asm volatile ("csrw " ++ std.fmt.comptimePrint("0x{x}", .{uvm32.IOREQ_PRINTLN}) ++ ", %[arg1]"
+        :
+        : [arg1] "r" (val.ptr),
+    );
+}
+
+pub inline fn printd(val: u32) void {
+    asm volatile ("csrw " ++ std.fmt.comptimePrint("0x{x}", .{uvm32.IOREQ_PRINTD}) ++ ", %[arg1]"
+        :
+        : [arg1] "r" (val),
+    );
+}
+
+pub inline fn printx(val: u32) void {
+    asm volatile ("csrw " ++ std.fmt.comptimePrint("0x{x}", .{uvm32.IOREQ_PRINTX}) ++ ", %[arg1]"
+        :
+        : [arg1] "r" (val),
+    );
+}
+
+pub inline fn printc(val: u32) void {
+    asm volatile ("csrw " ++ std.fmt.comptimePrint("0x{x}", .{uvm32.IOREQ_PRINTC}) ++ ", %[arg1]"
+        :
+        : [arg1] "r" (val),
+    );
+}
+
+pub inline fn yield() void {
+    asm volatile (std.fmt.comptimePrint("csrwi 0x{x}, 0", .{uvm32.IOREQ_YIELD}));
+}
+
+var millis_storage:u32 = 0;
+pub inline fn millis() u32 {
+    asm volatile ("csrw " ++ std.fmt.comptimePrint("0x{x}", .{uvm32.IOREQ_MILLIS}) ++ ", %[arg1]"
+        :
+        : [arg1] "r" (&millis_storage),
+    );
+    return millis_storage;
+}
+
+var getch_storage:u32 = 0;
+pub inline fn getch() ?u8 {
+    asm volatile ("csrw " ++ std.fmt.comptimePrint("0x{x}", .{uvm32.IOREQ_GETC}) ++ ", %[arg1]"
+        :
+        : [arg1] "r" (&getch_storage),
+    );
+    if (getch_storage <= 0xFF) {
+        return @truncate(getch_storage);
+    } else {
+        return null;
+    }
+}
+