And don't answer "to waste space of course" please. :)
And don't answer "to waste space of course" please. :)
Even today's machines often have a limit as to the offset that can be included in an instruction, so a compiler will have to use different machine instructions if a branch or load/store needs a larger offset. That would be another thing that this function might be useful to test. Actually that seems more likely.
It might be instructive to compare the binary size of this function to the offset length allowed in various PDP-11 machine instructions
" A second, less noticeable, but astonishing peculiarity is the space allocation: temporary storage is allocated that deliberately overwrites the beginning of the program, smashing its initialization code to save space. The two compilers differ in the details in how they cope with this. In the earlier one, the start is found by naming a function; in the later, the start is simply taken to be 0. This indicates that the first compiler was written before we had a machine with memory mapping, so the origin of the program was not at location 0, whereas by the time of the second, we had a PDP-11 that did provide mapping. (See the Unix History paper). In one of the files (prestruct-c/c10.c) the kludgery is especially evident. "