ASM Community

New version can be called in the same way
invoke htodw,addr HexString

it 13 bytes shorter and runs ~ 30-35% faster.
Based of ideas of previous roy+Svin version.
But stack frame optimized + someting else

      .386

      .model flat, stdcall  ; 32 bit memory model

      option casemap :none  ; case sensitive



    .code



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OPTION PROLOGUE:NONE

OPTION EPILOGUE:NONE



htodw         proc   FORCENOFRAME

ptHexString equ [esp+4]

                mov   ecx,ptHexString

                xor   edx,edx

ALIGN 4

htodw_loop:     

         mov al,[ecx] 

         inc ecx

         sub   al,"0"

         js   htodw_endloop

         shl   edx,4

         cmp   al,9

         jbe   htodw_addnumber

         sub   al,"a" - "0" - 10

         jns   htodw_addnumber

         add al,20h

htodw_addnumber: 	

          xor   dl,al

         jmp   htodw_loop



htodw_endloop:      mov   eax,edx

	ret 4

htodw         endp



OPTION PROLOGUE:DEFAULTOPTION

OPTION EPILOGUE:DEFAULTOPTION



; #########################################################################



end