[Pharo-project] RoarVM - Pharo and Squeak on Multicore

Igor Stasenko siguctua at gmail.com
Fri Nov 5 21:37:20 CET 2010

On 5 November 2010 16:49, Stefan Marr <pharo at stefan-marr.de> wrote:
> Hi:
> On 03 Nov 2010, at 23:59, Stefan Marr wrote:
>> Probably our VM is behaving slightly different from what the SqueakVM. (Not sure what the 'right' thing to do is thought)
>> From my understanding, the idea is that if there is no event, the primitive will fail.
>> And all other images have that case covered. They set the first array index to EventTypeNone.
>> Thus, "InputEventFetcher>>primGetNextEvent: array" should look like:
>> primGetNextEvent: array
>>       "Store the next OS event available into the provided array.
>>       Essential."
>>       <primitive: 94>
>>       array at: 1 put: EventTypeNone. "STEFAN: Added this line"
>>       ^nil
>> However, since Pharo works on the other VM, I guess the primitive there is filling in the first slot of the array anyway.
>> So, what is the specification? I think the primitives have changed since 'the bluebook'.
> Just to ask that question again: What is the conclusion, is the bug in the image or in the VM?

Here the Squeak implementation of it:

primGetNextEvent: array
	"Store the next OS event available into the provided array.
	Essential. If the VM is not event driven the ST code will fall
	back to the old-style mechanism and use the state based
	primitives instead."
	| kbd buttons modifiers pos mapped |
	<primitive: 94>
	"Simulate the events"
	array at: 1 put: EventTypeNone. "assume no more events"

	"First check for keyboard"
	kbd := super primKbdNext.
	kbd = nil ifFalse:[
		"simulate keyboard event"
		array at: 1 put: EventTypeKeyboard. "evt type"
		array at: 2 put: Time millisecondClockValue. "time stamp"
		array at: 3 put: (kbd bitAnd: 255). "char code"
		array at: 4 put: EventKeyChar. "key press/release"
		array at: 5 put: (kbd bitShift: -8). "modifier keys"

	"Then check for mouse"
	buttons := super primMouseButtons.
	pos := super primMousePt.
	modifiers := buttons bitShift: -3.
	buttons := buttons bitAnd: 7.
	mapped := self mapButtons: buttons modifiers: modifiers.
	(pos = mousePosition and:[(mapped bitOr: (modifiers bitShift: 3)) =
		at: 1 put: EventTypeMouse;
		at: 2 put: Time millisecondClockValue;
		at: 3 put: pos x;
		at: 4 put: pos y;
		at: 5 put: mapped;
		at: 6 put: modifiers.

so, i assume that problem is in Pharo , which does not handling a
primitive failure correctly (by setting
array at: 1 put: EventTypeNone. )

> Thanks
> Stefan
> --
> Stefan Marr
> Software Languages Lab
> Vrije Universiteit Brussel
> Pleinlaan 2 / B-1050 Brussels / Belgium
> http://soft.vub.ac.be/~smarr
> Phone: +32 2 629 2974
> Fax:   +32 2 629 3525

Best regards,
Igor Stasenko AKA sig.

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