On 13-Jul-07, at 4:42 PM, sig wrote:

> Hello, squeak-dev,
>
> I found, that numeric primitive table in squeak have many gaps, filled
> with 'primitiveFail', and with comments like 'no longer used' and
> other..
> Id like to use one of the slots, but have no idea, what number is
> really safe for use?
> Any suggestions/reasoning?

You don't get to use numbered primitives. That is reserved for those  
of us with god-like powers.

Seriously, unless you are doing something quite extraordinary, don't  
even think about using numbered primitives. Write a simple named  
primitive and put it in a plugin if at all possible. If you really  
can't manage that, write a named primitive that will get left in the  
vm core.

See, for example -
Interpreter>primitiveDisablePowerManager
	"Pass in a non-negative value to disable the architectures  
powermanager if any, zero to enable. This is a named (not numbered)  
primitive in the null module (ie the VM)"

	| integer |
	self export: true.
	integer := self stackIntegerValue: 0.
	successFlag ifTrue: [
		self ioDisablePowerManager: integer.
		self pop: 1].  "integer; leave rcvr on stack"
and usage-
PowerManagement class>disablePowerManager: aInteger
	"Disable/Enable the architectures power manager by passing in nonzero
	or zero"
	<primitive: 'primitiveDisablePowerManager'> "primitiveExternalCall"
	^ self

There is no advantage to numbered primitives. Once the method lookup  
has been done the primitive function's address is stored in the cache  
so any primitive gets exactly the same treatment at that level. IF I  
had the time to spare I would have had a go at removing numbered  
prims altogether.

tim
--
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Do files get embarrassed when they get unzipped?