Why are variables in C named so obscurely? Why rndval instead of random_value, for example? Autocomplete barely existed back then, and was something performed

Why are variables in C named so obscurely? Why rndval instead of random_value, for example? Autocomplete barely existed back then, and was something performed by purpose-built TSRs that maintained their own text expansion dictionaries, rather than a thing your text editor automatically did by scanning the current file for things you might be trying to type. "r a n d o m shift - v a l u e" is a lot more to type by hand than "r n d v a l". And even if you did have that you'd still have to deal with coding on a textmode screen that was probably 80x50 characters. Maybe 132x60 if you had a really top-of-the-line video card. Not much room for those long variable names. (Admittedly the C code under discussion was written long after the original assembly routine was written, but by someone who'd spent a lot of time with his head in the source of these games, absorbing the idioms of early-nineties programming.)