Possible bug in atomicOp

[Benjamin Thaut]

Am 23.10.2010 14:52, schrieb dsimcha:
> == Quote from Benjamin Thaut (code at benjamin-thaut.de)'s article
>> The following testcase (when executed on dual core at least) results in
>> a endless loop inside atomicOp.
>> import std.stdio;
>> import std.concurrency;
>> enum Messages {
>> 	GO,
>> 	END
>> }
>> shared class Account {
>> 	private double amount = 0;
>> 	double getAmount() const {
>> 		return amount;
>> 	}
>> 	void change(double change){
>> 		atomicOp!"+="(amount,change);
>> 	}
>> }
>> shared Account bank = null;
>> void otherThread(Tid father){
>> 	send(father,Messages.GO);
>> 	for(int i=0;i<1000;i++)
>> 		bank.change(-100);
>> 	send(father,Messages.END);
>> }
>> void main(string[] args)
>> {
>> 	bank = new Account();
>> 	spawn(&otherThread,thisTid);
>> 	receiveOnly!(Messages)();
>> 	for(int i=0;i<1000;i++)
>> 		bank.change(+100);
>> 	receiveOnly!(Messages)();
>> 	writefln("Program finished. Amount is %s",bank.getAmount());
>> }
>> Is this a bug, or am I doing something wrong here?
>> If it is a bug it is kind of critical because people which are reading
>> the "the D programming language" book won't be happy to find out that
>> some of the given examples do not work yet.
>
> http://d.puremagic.com/issues/show_bug.cgi?id=4782
>
> Basically, atomicLoad (which atomicOp uses) always returns in ALU registers.
> Floating point numbers need to be returned in floating point registers.
> Therefore, a NaN always gets returned from atomicLoad!double, and a NaN isn't
> equal to anything.

So shouldn't there be a static assert to prevent one from using atomicOp 
with floats and doubles? Or should atomicLoad be implemented to support 
floats and doubles?

-- 
Kind Regards
Benjamin Thaut