I always suspected the overflow conversions were UB, but with gcc doing
different things on arm, I thought it was about time to abandon those
particular tests. What I was not expecting was for the return value of
strcmp to be "UB" (in that there's no guarantee of the exact value, just
< = > 0). Fortunately, nothing actually relies on the value of the op
other than the tests, so modify the test to make the behavior well
defined.
The tests fail due to differences in how clang and gcc treat floating
point to unsigned integral type conversions when the values overflow. It
wouldn't be so bad if clang was consistent with conversions to 32-bit
unsigned integers, like it seems to be with conversion to 64-bit
unsigned integers.
With this, the "get QF building with clang" mini-project is done and I
won't have to panic when someone comes to me and asks if it will work.
At worst, there'll be a little bit-rot.
ANY/ALL/NONE have been temporarily removed until I implement the HOPS
(horizontal operations) sub-instructions, which will all both 32-bit and
64-bit operands and several other operations (eg, horizontal add).
All the fancy addressing modes for the conditional branch instructions
have been permanently removed: I decided the gain was too little for the
cost (24 instructions vs 6). JUMP and CALL retain their addressing
modes, though.
Other instructions have been shuffled around a little to fill most of
the holes in the upper block of 256 instructions: just a single small
7-instruction hole.
Rearrangements in the actual engine are mostly just to keep the code
organized. The only real changes were the various IF statements and
dealing with the resulting changes in their addressing.
Most useful for 64-bit values as only one instruction is needed to move
the data around rather than two, but could be slightly faster for 32-bit
as the addressing is simpler (needs profiling).
It calculating only the size of the array (which was often 4 or 8
globals per element) proved to be a pain when I forgot to alter the size
for the new scale tests. Fixing the size calculation even found a bug in
the shiftop tests.
It seems casting from float/double to [unsigned] int/long when the value
doesn't fit is undefined (which would explain the inconsistent results).
Mentioning the possibility seems like a good idea should the results for
such casts change and cause the tests to fail.
