[cc65] Bug in signed comparisions!

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From: Piotr Fusik (P.Fusik_at_elka.pw.edu.pl)
Date: 2002-04-17 09:35:24 

Signed comparisions give incorrect results, if the difference between
compared numbers is >=0x8000 (for ints) or >=0x80000000 (for longs).
In the attached test program, compiled with cc65 2.8.0, the condition
-0x7fff < 0x7fff is FALSE. That's because, for signed integers,
"less than" condition should be computed as N_flag^V_flag rather than
by simply testing the N flag.

I include fixed icmp and lcmp runtime functions. Fixes are also needed
for optimized inline compares.

BTW.
cc65 -O test.c
prints:
The instruction at 0x0040d980 referenced memory at 0xffffffff.
The memory could not be read.

Bye,
Piotr
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