Zap crash escaping from loop

1.49 (13 Jun 2020) rick-07

Zap has a facility to leave infinite loops, for example press Ctrl-Esc to get a command line and enter “while (1) : endwhile”. You’ll get an hourglass, and Alt-Esc should offer you an error box to get out of it.

On my computer however I get a data abort. I think the problem is that query_abort in s.Commands calls zap_query (the Zap call that gives you the error box) without setting R3 to anything. R3 should either be 0 or point to a sprite name. In my case R3 ends up being &40000001, which XWimp_ReportError doesn’t like.

A solution would be to put MOV R3,#0 before BL zap_query; you’ll then get the error box appearing correctly with the Zap icon and you can merrily leave your loop.