30+ year old STOS compiler bug found ?

[exxos]

This has been driving me nuts for the past 3 weeks. I think I finally found the problem. People need to also confirm they see the same problem in the first place.

DOWNLOAD TEST BAS

https://www.exxosforum.co.uk/atari/STOS ... BENCH3.BAS

MUST USE TOS 104. CLEAN SYSTEM. Can use Steem or real hardware. MUST USE 206 or 300 compiler. MUST compile to GEM to DISK.
Once compiled. quit back to desktop using SYSTEM.

You should see the desktop icons corrupted !

My investigation shows the compiler has a bug that "randomly" writes (massive over simplification!) to areas of memory it shouldn't. . In this particular case, its the RSC ICON DATA in memory. The fault does not show in TOS206 or EMUTOS as the data landed in a "less visible" place in memory. The corruption ALWAYS happens, but needs TOS104 to visually see it in my specific test.

If you change the length of the DATA at the end of the BAS. The corruption will "move". If you remove all the DATA 0,0,0 lines, the corruption will "vanish". Same will happen with commands, but using DATA lines was just simple to demonstrate this bug !

I've found all sorts of related bugs as well and been working though to find and fix them all in a updated build of STOS.