Contrast that C code with:

    pub fn parseYear4(text: *const [4]u8) !u16 {
        const nnnn: @Vector(4, u16) = .{ text[0], text[1], text[2], text[3] };
        const zero: @Vector(4, u16) = .{ '0', '0', '0', '0' };
        const mmmm: @Vector(4, u16) = .{ 1000, 100, 10, 1 };
        const result = @reduce(.Add, (nnnn -% zero) *% mmmm);
        if (result > 9999) return error.CertificateTimeInvalid;
        return result;
    }

source: https://github.com/ziglang/zig/blob/fc9ab5f0e838196e99d1706e...

machine code example: https://godbolt.org/z/ezrPEdPx7