    const std = @import("../../std.zig");

    const bits = switch (@import("builtin").cpu.arch) {
        .mips,
        .mipsel,
        .mips64,
        .mips64el,
        .powerpc,
        .powerpcle,
        .powerpc64,
        .powerpc64le,
        .sparc,
        .sparc64,
        .sparcel,
        => .{ .size = 13, .dir = 3, .none = 1, .read = 2, .write = 4 },
        else => .{ .size = 14, .dir = 2, .none = 0, .read = 2, .write = 1 },
    };

    const Direction = std.meta.Int(.unsigned, bits.dir);

    pub const Request = packed struct {
        nr: u8,
        io_type: u8,
        size: std.meta.Int(.unsigned, bits.size),
        dir: Direction,
    };

    fn io_impl(dir: Direction, io_type: u8, nr: u8, comptime T: type) u32 {
        const request = Request{
            .dir = dir,
            .size = @sizeOf(T),
            .io_type = io_type,
            .nr = nr,
        };
        return @bitCast(u32, request);
    }

    pub fn IO(io_type: u8, nr: u8) u32 {
        return io_impl(bits.none, io_type, nr, void);
    }

    pub fn IOR(io_type: u8, nr: u8, comptime T: type) u32 {
        return io_impl(bits.read, io_type, nr, T);
    }

    pub fn IOW(io_type: u8, nr: u8, comptime T: type) u32 {
        return io_impl(bits.write, io_type, nr, T);
    }

    pub fn IOWR(io_type: u8, nr: u8, comptime T: type) u32 {
        return io_impl(bits.read | bits.write, io_type, nr, T);
    }

    comptime {
        std.debug.assert(@bitSizeOf(Request) == 32);
    }