bit bashing
n.
(alt. : bit diddling or bit twiddling) Term used to describe any of several kinds of low-level programming characterized by manipulation of bit, flag, nybble, and other smaller-than-character-sized pieces of data; these include low-level device control, encryption algorithms, checksum and error-correcting codes, hash functions, some flavors of graphics programming (see bitblt), and assembler/compiler code generation. May connote either tedium or a real technical challenge (more usually the former). “The command decoding for the new tape driver looks pretty solid but the bit-bashing for the control registers still has bugs.” See also mode bit.