It was the old compiler they "fixed"

the compiler “optimized” the code by unrolling the loop into 65,536 individual “write byte to memory” instructions, each 4 bytes long.

All in all, it took this program 256 kilobytes of code to initialize 64 kilobytes of data.

This offended the team so much that they added special code to the translator to detect this horrible function and replace it with the equivalent tight loop.