unit FastcodeStrCompUnit;

//Version : 0.1 Preliminary version
//Only direct calling supported

interface

function StrCompFastcodeP3(const Str1, Str2: PChar): Integer;
function StrCompFastcodeP4(const Str1, Str2: PChar): Integer;
//function StrCompFastcodePrescott(const Str1, Str2: PChar): Integer;
function StrCompFastcodeOpteron(const Str1, Str2: PChar): Integer;
function StrCompFastcodeXP(const Str1, Str2: PChar): Integer;
function StrCompFastcodeRTL(const Str1, Str2: PChar): Integer;
function StrCompFastcodeBlended(const Str1, Str2: PChar): Integer;
function StrCompFastcodePascal(const Str1, Str2: PChar): Integer;

implementation

//Author:            Aleksandr Sharahov
//Date:              N/A
//Optimized for:     P3
//Instructionset(s): N/A
//Original Name:     StrCompSha3

function StrCompFastcodeP3(const Str1, Str2: PChar): Integer; assembler;
asm
   sub   edx, eax //pointers MUST be not NULL
@next:
   movzx ecx, [eax+edx]
   add   eax, 1
   test  cl, cl
   jz    @last
   cmp   cl, [eax-1]
   je    @next
@last:
   movzx eax, [eax-1]
   sub   eax, ecx
   end;

//Author:            Aleksandr Sharahov
//Date:              N/A
//Optimized for:     P4
//Instructionset(s): N/A
//Original Name:     StrCompSha3

function StrCompFastcodeP4(const Str1, Str2: PChar): Integer; assembler;
asm
   sub   edx, eax //pointers MUST be not NULL
@next:
   movzx ecx, [eax+edx]
   add   eax, 1
   test  cl, cl
   jz    @last
   cmp   cl, [eax-1]
   je    @next
@last:
   movzx eax, [eax-1]
   sub   eax, ecx
   end;

//Author:            Aleksandr Sharahov
//Date:              N/A
//Optimized for:     XP
//Instructionset(s): N/A
//Original Name:     StrCompSha3

function StrCompFastcodeXP(const Str1, Str2: PChar): Integer; assembler;
asm
   sub   edx, eax //pointers MUST be not NULL
@next:
   movzx ecx, [eax+edx]
   add   eax, 1
   test  cl, cl
   jz    @last
   cmp   cl, [eax-1]
   je    @next
@last:
   movzx eax, [eax-1]
   sub   eax, ecx
   end;

//Author:            Aleksandr Sharahov
//Date:              N/A
//Optimized for:     Opteron
//Instructionset(s): N/A
//Original Name:     StrCompSha3

function StrCompFastcodeOpteron(const Str1, Str2: PChar): Integer; assembler;
asm
   sub   edx, eax //pointers MUST be not NULL
@next:
   movzx ecx, [eax+edx]
   add   eax, 1
   test  cl, cl
   jz    @last
   cmp   cl, [eax-1]
   je    @next
@last:
   movzx eax, [eax-1]
   sub   eax, ecx
   end;

//Author:            Aleksandr Sharahov
//Date:              N/A
//Optimized for:     RTL
//Instructionset(s): N/A
//Original Name:     StrCompSha3

function StrCompFastcodeRTL(const Str1, Str2: PChar): Integer; assembler;
asm
   sub   edx, eax //pointers MUST be not NULL
@next:
   movzx ecx, [eax+edx]
   add   eax, 1
   test  cl, cl
   jz    @last
   cmp   cl, [eax-1]
   je    @next
@last:
   movzx eax, [eax-1]
   sub   eax, ecx
   end;

//Author:            Aleksandr Sharahov
//Date:              N/A
//Optimized for:     Blended
//Instructionset(s): N/A
//Original Name:     StrCompSha3

function StrCompFastcodeBlended(const Str1, Str2: PChar): Integer; assembler;
asm
   sub   edx, eax //pointers MUST be not NULL
@next:
   movzx ecx, [eax+edx]
   add   eax, 1
   test  cl, cl
   jz    @last
   cmp   cl, [eax-1]
   je    @next
@last:
   movzx eax, [eax-1]
   sub   eax, ecx
   end;

//Author:            Aleksandr Sharahov
//Date:              N/A
//Optimized for:     Pascal
//Instructionset(s): N/A
//Original Name:     StrCompShaPas3

function StrCompFastcodePascal(const Str1, Str2: PChar): Integer;
var
  ch, dist: integer;
  p: pchar;
begin;
   p:=str1;
   dist:=str2-p;
   repeat;
     ch:=shortint(p[dist]);
     inc(p);
     until (ch=0) or (byte(ch)<>byte(p[-1]));
   Result:=ord(p[-1])-byte(ch);
   end;

end.