[fpc-devel] *** GMX Spamverdacht *** Re: Broken frac function in FPC3.1.1 / Windows x86_64

[Florian Klämpfl]

Am 28.04.2018 um 15:33 schrieb Thorsten Engler:

> procedure XXX1;
> asm
>   .noframe
>   nop
>   nop // added this
> end;

I did not look at the code in detail but I suspect this is caused by the two branches:

  cmp       edx, $43300000
  jge      @@zero
  cmp       edx, $3FE00000
  jbe      @@skip


If two branches are in the same 16 byte block, they share a branch prediction entry on almost all
x86 processors and branch prediction suffers very much in this case.

So something like

  cmp       edx, $43300000
  jge      @@zero
  cmp       edx, $3FE00000
  .align   16
  jbe      @@skip

might be much better.