Delphi Embedded Assembly for beginners [28]-Three methods and efficiency of setting eax value to 0

// The functions of the following three functions are the same, but the efficiency is different {fun1 needs to read constant 0, slowest} function fun1: integer; ASM mov eax, 0end; {fun2 and fun3 are only the registers that operate the CPU, which are faster than fun1} function fun2: integer; ASM sub eax, eaxend; {fun3 fastest} function fun3: integer; asm xor eax, eaxend; // speed test procedure tform1.button1click (Sender: tobject); var T: Cardinal; I: integer; begin T: = gettickcount; for I: = 0 to 100000000 do fun1; t: = gettickcount-T; showmessage (inttostr (t); {ALL: more than 600} t: = gettickcount; for I: = 0 to 100000000 do fun2; t: = gettickcount-T; showmessage (inttostr (t); {ALL: more than 500} t: = gettickcount; for I: = 0 to 100000000 do fun3; t: = gettickcount-T; showmessage (inttostr (t); {ALL: more than 400} end;