On Fri, 5 Sep 2003, Joshua 'Schwa' Gargus wrote:

> Did you ever resolve this issue?
> I haven't gotten too far with debugging this.

I just tried with the latest Debian compiler on 386.

The problem is in the interpreter, not in the plugin.  And it looks like a
compiler bug.

double stackFloatValue(int offset) is the culprit.  Inserting

	printf("result == %lf\n", result);

just before the return causes it to start working (so it's definitely a
compiler problem).  Declaring result as static causes the function to
return the value fetched from the Float on the previous call (i.e., the
result is out of sync by 1 function call).  Conclusion: fetchFloatAtinto()
is working but the compiler is loading the double return value from result
before actually doing the fetch.

You should switch to a different compiler until it's fixed (and file a
report to gcc-bugs, if you'd like it to be fixed any time soon ;).

If that's not an option then one possible expedient hack is to insert an
empty asm statement [*] before the return from stackFloatValue() like this

	fetchFloatAtinto(floatPointer + BaseHeaderSize, result);
	asm("");
	return result;

and recompile your VM.  (But there is no telling how many other float
functions are similarly afflicted, so I don't recommend this as a
solution.)

Ian

[*] This works because the insn scheduler will not move loads across a
basic block boundary, and it considers any asm() statement -- even an
empty one -- to be a boundary.