adding writing memory

src/main.zig

@@ -4,7 +4,11 @@ const mem = @import("memory.zig");
 pub fn main() !void {
     var memory = mem.Memory.init();
     var input = std.io.getStdIn().reader();
-    std.debug.print("MI-HA-RU (386) REPL\nType 'exit' to quit.\n", .{});
+    std.debug.print(
+        \\MI-HA-RU (386) REPL
+        \\Type 'exit' to quit.
+        \\
+    , .{});
     var buffer: [256]u8 = undefined;
     while (true) {
         std.debug.print("> ", .{});
@@ -25,8 +29,28 @@ pub fn main() !void {
 
 fn handleMemoryCommand(memory: *mem.Memory, it: anytype) !void {
     if (it.next()) |next_argument| {
-        const addr = try std.fmt.parseUnsigned(u8, next_argument, 10);
+        if (std.mem.eql(u8, next_argument, "read")) {
-        const value = try memory.readByte(addr);
+            if (it.next()) |address| {
-        std.debug.print("{}\n", .{value});
+                const addr = try std.fmt.parseUnsigned(u8, address, 10);
+                const value = try memory.readByte(addr);
+                std.debug.print(
+                    \\MEM @ {}: {}
+                    \\
+                , .{ addr, value });
+            }
+        } else if (std.mem.eql(u8, next_argument, "write")) {
+            const maybe_addr = it.next();
+            const maybe_value = it.next();
+            if (maybe_addr == null or maybe_value == null) {
+                std.debug.print(
+                    \\Invalid arguments. Usage: mem write <addr> <value>
+                    \\
+                , .{});
+            } else {
+                const addr = try std.fmt.parseUnsigned(u8, maybe_addr.?, 10);
+                const value = try std.fmt.parseUnsigned(u8, maybe_value.?, 10);
+                _ = try memory.writeByte(addr, value);
+            }
+        }
     }
 }

src/memory.zig

@@ -12,4 +12,8 @@ pub const Memory = struct {
     pub fn readByte(self: *Memory, addr: u8) !u8 {
         return self.data[addr];
     }
+
+    pub fn writeByte(self: *Memory, addr: u8, value: u8) !void {
+        self.data[addr] = value;
+    }
 };