The first two functions ported are faster IntToStr functions written 100% in assembly. The functions are 500 up to 1000% faster than original RTL functions, depending on the compiler (almost 1000% faster in Delphi 2006, almost 500% faster in Delphi XE2 - 32 bits). The code cannot be used in XE2 64 bit projects, because ASM 64 is a different beast. Maybe I will port other functions as well (things that don't violate copyright material), but many of them are already addressed in RtlVclOptimize (from Andreas Hausladen).
I created an unit called uCBRTLPatch.pas, containing two functions:
function FastIntToStr(Value: Integer): string; function FastInt64ToStr(Value: Int64): string;
These functions will replace (patch) original IntToStr functions in runtime (for Integer and Int64 parameters).
To use it, you just have to add uCBRTLPatch.pas to your .DPR uses clause and you are done. You can donwload uCBRTLPatch.pas here.