Sunday, July 12, 2015

I finally found the problem. One of the four descriptions for the division instruction in was wrong. All of the other descriptions forced the numerator to be in a register, this one allowed anything. So this let the constant 3200 be used directly, without the need to be stored in register. When that form was expanded, gen_highpart was called, resulting in the crash.

The error only showed up in this code because it contains lots of calculations, increasing the pressure on the compiler to make more efficient use of the registers. While doing that calculation it saw that the division form did not require a register and acted accordingly. The normal behavior is to put all values in registers before use. For less demanding code, that register usage would be left in place, and no error would be seen.

Once that was fixed, wolfie3 compiles without any problems, and the resulting assembly is correct. Yay!

Before I do any other releases, I want to try to make a cygwin archive for the windows people. I've been neglecting that for a long time.

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