On Wed, 29 Apr 2009 09:17:16 +0200, Igor Stasenko wrote:

> In VM w/o closures, i implemented a new primitive,
> #primitiveInterrupt, which looks like following:
>
> primitiveInterrupt
> 	"primitive"
> 	| context interruptProcess sched oldProc |
> 	self export: true.
> 	context := self stackTop.
>
> 	sched := self schedulerPointer.
> 	"check that we using a new scheduler , which having additional
> instance variables:
> 	 - interruptProcess
> 	 - interruptedProcess"
> 	(self lastPointerOf: sched) >= (InterruptedProcessIndex *
> BytesPerWord + BaseHeaderSize)
> 		ifFalse: [ ^ self primitiveFail ].
>
> 	oldProc := self fetchPointer: ActiveProcessIndex ofObject: sched.
> 	interruptProcess := self fetchPointer: InterruptProcessIndex ofObject:  
> sched.
> 	oldProc == interruptProcess ifTrue: [
> 		"we are already in interrupt, proceed as with sending #value to block"
> 		^ self primitiveValue
> 		].

Check(s) may lack this: any process can be in any state including the ones  
which you do not want and the ones which #transferTo: does not want.

> 	self storePointer: InterruptedProcessIndex ofObject: sched withValue:  
> oldProc.
> 	self storePointer: SuspendedContextIndex ofObject: interruptProcess
> withValue: context.
> 	self putToSleep: oldProc.
> 	self transferTo: interruptProcess.
>
> 	self pop: 1 thenPush: self nilObject
> 	
>
> A primitive is hooked in
> BlockContext>>primInterrupt :
>
> primInterrupt
> 	"Primitive. Evaluate the block in special interrupt process"
> 	<primitive: 'primitiveInterrupt' module: ''>
> 	self primitiveFail
>
>
> And code, which is using it looks like following:
>
> Processor>>interruptWith: aBlock
> 	"Interrupt the currently running process to evaluate given block
> argument inside
> 	interrupt process"
> 	| result |
> 	[ result := aBlock value.  activeProcess suspend. ] asContext  
> primInterrupt.
> 	^ result

(activeProcess suspend) you mean an instVar ??

> the VM crashing at attempt to return from aBlock value (it never gets
> to the point for evaluating 'activeProcess suspend').
>
> if i write code like following:
>
> Processor>>interruptWith: aBlock
> 	"Interrupt the currently running process to evaluate given block
> argument inside
> 	interrupt process"
> 	| result |
> 	[ [ result := aBlock value. ] value  activeProcess suspend. ]
> asContext primInterrupt.
> 	^ result

Now with #activeProcess you are sending, versus the instVar above ??

> Then VM does not crashing, but silenty quits to OS.

Good luck :)

> The only way how i managed to make it work, is to do it as:
>
> Processor>>interruptWith: aBlock
> 	"Interrupt the currently running process to evaluate given block
> argument inside
> 	interrupt process"
> 	[ self runBlock: aBlock ] asContext primInterrupt.
>
> and runBlock: aBlock is:
>
> runBlock: aBlock
> 	
> 	aBlock value.
> 	activeProcess suspend.
>
> it works fine, except that i unable to use the returned result. - i
> could put it to instance variable.. but its a bit awkward :(
>
> I suspect this somehow connected with the return to context who having
> sender = nil. (a bottom context of process always having sender =
> nil).
> But i wonder, why my code not working, while code, which used for
> #fork, it does? Any suggestions?
>
> newProcess
> 	"Answer a Process running the code in the receiver. The process is not
> 	scheduled."
>
> 	<primitive: 19> "Simulation guard"
> 	^ Process
> 		forContext:
> 			[self value.
> 			Processor terminateActive] asContext
> 		priority: Processor activePriority
>
> here, the initial context of newly created process will point to:
>
> [self value. Processor terminateActive]
>
> and in my case, an initial context of interrupt process is set in
> #primitiveInterrupt and points to:
> [ result := aBlock value.  activeProcess suspend. ]
>
> why i works for above case, but not for mine, no idea...
>

-- 
"If at first, the idea is not absurd, then there is no hope for it".  
Albert Einstein