Re: RFA: performance improvement for PowerPC disassembly

[James Lemke <jwlemke at codesourcery dot com>]

On 03/16/2012 08:13 AM, Alan Modra wrote:
> On Thu, Mar 15, 2012 at 10:32:36PM +1030, Alan Modra wrote:
> > >  The middle of print_insn_powerpc should then look like
> [snip]
>
> As suggested, this splits out the opcode lookup, and makes some
> further tweaks that speed up powerpc disassembly a few percent.
>
> 	* ppc-dis.c (PPC_OPC_SEGS, PPC_OP_TO_SEG): Delete.
> 	(powerpc_opcd_indices): Bump array size.
> 	(disassemble_init_powerpc): Set powerpc_opcd_indices entries
> 	corresponding to unused opcodes to following entry.
> 	(lookup_powerpc): New function, extracted and optimised from..
> 	(print_insn_powerpc): ..here.

Cool.  The search is now bounded to one of the calculated opcode table 
segments.  Wouldn't it be preferable to keep a #define for the number of 
segments versus having 64 or 65 in various places?
Cheers, Jim.

--
Jim Lemke
Mentor Graphics / CodeSourcery
Orillia Ontario,  +1-613-963-1073