Mmm I think Ian dropped in my suggested change

#if defined(__powerpc__) || defined(PPC) || defined(_POWER) ||  
defined(_IBMR2) || defined(__ppc__)
# define JUMP_TABLE_PTR	; register void **jumpTableP JP_REG;  
jumpTableP= &jumpTable[0]
# define BREAK		goto *jumpTableP[currentBytecode]
#else
# define JUMP_TABLE_PTR
# define BREAK		goto *jumpTable[currentBytecode]
#endif

where for the powerpc it now uses the jumpTableP logic.

But just to obsolete things for him, I'll point out that this also  
makes a difference for 68K machines
I think my #if also ORS against defined (__APPLE__)
because on April 5th 2002 I noted:

> # define JP_REG asm("a3")
>
> that makes the jump
> movel a3@(d7:l:4),a0
> mp a0@
>
> versus the old code which is
>
> lea _jumpTable.325,a0
> movel a0@(d7:l:4),a0
> jump a0@
>
> I think it is 8 clock cycles faster when we avoid the lea. I'd guess  
> the _jumpTable.325 resolves to register+offset
>
> Note that is for each bytecode executed! So it does have an impact on  
> performance.
>
> This changes bytecodes/sec
> 1,439,884. 51098 sends/sec
> to
> 1,550,387. 55080

Removal of instructions on 68K machines DOES make things faster.  
Removal of instructions on
newer machines might not make a difference. Other folks INTEL and ARM  
might what to check
assembler output and see what the
goto *jumpTableP[currentBytecode]
verus
goto *jumpTable[currentBytecode]

does from an assembler and performance viewpoint.
--
======================================================================== 
===
John M. McIntosh <johnmci at smalltalkconsulting.com> 1-800-477-2659
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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