[fpc-devel] TFPHashList (Was: Alternative parsers)

[Dariusz Mazur]

  W dniu 2010-10-22 23:30, Florian Klämpfl pisze:
> Am 22.10.2010 23:17, schrieb Dariusz Mazur:
>> full source in attachment (should I prepare it different?)
> The best would be a diff against compiler sources.

OK. First I  find better computing of hash. My is slight worse than 
current (but overall faster)

>> Second: when I review assembler list I've notice some strange lines (all
>> optimizations are enabled):
>>
> Which compiler version? 2.4.x? I think r15502 in trunk should fix this.
2.5.1 but older. Now I test from current. Its better (faster) but  I 
found other strange:

first: dec(i) is translate to three lines
     movl    %esi,%eax
     decl    %eax
     movl    %eax,%esi

why not simple decl %esi ?
When variable is in %ebx things are the same.


second  if I have:
   while ii>0 do begin
      ....;
    dec(ii);


assembler look:


# [121] while ii>0 do begin
     jmp    .Lj16  //<  here add first test of ii
     .balign 4,0x90
.Lj15:
.Ll8:
# [122] result:=LongWord(result *8010817  ) xor (Pw^);
.Ll10:
# [124] dec(ii);
     movl    %esi,%eax
     decl    %eax
     movl    %eax,%esi
.Lj16:
     testl    %esi,%esi    //<--  this can be avoid, because test from DECL
     jg    .Lj15


Is this possible to achieve this optimizations,
If yes, can somebody help, from which file I should start





-- 
   Darek