0b1001111111

0b1001111111 is a binary literal used in programming to denote a specific unsigned integer. It consists of ten bits, with the most significant bit set and the next two bits clear, and the remaining seven lower bits all set to 1. In binary form, the value is 1 00 1111111.

The decimal value of 0b1001111111 is 639. In hexadecimal, this number corresponds to 0x27F. This places the value in the mid-to-upper range of the 10-bit unsigned interval (0 to 1023).

If interpreted as a signed 10-bit two's complement number, 0b1001111111 represents -385, since unsigned 639 minus 1024 equals -385. This illustrates how the same bit pattern can denote different values depending on signedness and bit width.

In programming and computer science, the 0b prefix indicates a binary literal in several languages, including Python, JavaScript (ECMAScript 6 and later), C++14, and Rust. Such literals enable precise bit-level manipulation, masking, setting or testing flags, and other low-level operations common in systems and embedded programming.

Summary: 0b1001111111 encodes the unsigned integer 639 (0x27F) in 10-bit binary; its interpretation changes with signedness, yielding -385 in 10-bit two's complement.