Hex Conversion

[Bob Zale]

Here's an interesting little subroutine, similar to one published in a recent issue of the PowerBASIC Gazette. It converts a binary value in register AL (0-255) to the equivalent ASCII hex digits (00-FF). The hi-order hex digit is returned in register DL, the lo-order hex digit in register DH, so you can easily store it in memory with: MOV [MemoryWord], DX.

Bin8ToHex:
         push    eax
         ror     al, four
         call    Bin8a
         mov     dl, dh
         pop     eax
Bin8a:
         and     al,00001111b
         add     al,90h
         daa
         adc     al,40h
         daa
         mov     dh, al
         ret

[Edwin Knoppert]

Very interesting to me.
Is it possible to extend this to place these tow bytes into a dynamic string?
For conversion i would like to populate a dynamic string of twice the size of a binary string, so the target address must shift on each conversion.

Or is a native functionality equally fast?
I use conversion to hex very often.

Thanks,

[Michael Mattias]

Is it possible to extend this to place these tow bytes into a dynamic string?
For conversion i would like to populate a dynamic string of twice the size of a binary string, so the target address must shift on each conversion.

Yes. http://www.powerbasic.com/support/pb...ad.php?t=25176

(Assumes: No Assembly Required).

[Edwin Knoppert]

I already do the same.

[Michael Mattias]

Well, OK.

What Mr. Zale posted does not do quite the same thing.....

... which is why, I guess, he posted this in the first place. After all, he has already created his own very fine HEX$() function to put numbers into hex character strings, and that works pretty well.

[John Gleason]

Edwin, I got about 17x faster using the below code:

#COMPILE EXE
#DIM ALL
MACRO Bin8ToHex()
        !push    eax
        !ror     al, 4
        !call    Bin8a
        !mov     dl, dh
        !pop     eax
        !call    Bin8a
        EXIT MACRO
    Bin8a:
        !and     al,&b00001111
        !add     al,&h90
        !daa
        !adc     al,&h40
        !daa
        !mov     dh, al
        !ret
END MACRO

FUNCTION PBMAIN () AS LONG
   LOCAL wrdVar AS WORD, ii AS LONG, hexStr AS STRING
   LOCAL convStrPtr AS LONG, convStr, convStr2, cErr AS STRING, t, t2, t3 AS SINGLE
   
   convStr = SPACE$(40000000)
   convStrPtr = STRPTR(convStr)
   t = TIMER
   FOR ii = 0 TO 20000000 - 1
      !mov eax, ii
      Bin8ToHex
      !mov wrdVar, dx
      POKE WORD, convStrPtr + 2 * ii, wrdVar
   NEXT
   t2 = TIMER
   convStr2 = convStr
   
   FOR ii = 0 TO 20000000 - 1
      
      POKE$ convStrPtr + 2 * ii, HEX$(ii, 2)
      
   NEXT
   t3 = TIMER
   IF convStr2 <> convStr THEN cErr = "oops, there is an error"
   ? "asm took " & STR$(t2 - t, 4) & $CRLF & _
     "hex took " & STR$(t3 - t2, 4) & " so asm was" & _
      STR$((t3 - t2) / (t2 - t), 4) & " times faster" & $CRLF & cErr
END FUNCTION

[Bob Zale]

Store repeated hex bytes in a buffer (string) addressed by EDI:

Start:
          cld
          lea       edi, TargetOffset
          mov       al, BinNumber
          call      Bin8ToHex
          <RepeatAsNeeded>
          <exit>

Bin8ToHex:
           push        eax
           ror         al, four
           call        Bin8a
           pop         eax
Bin8a:
           and         al,00001111b
           add         al,90h
           daa
           adc         al,40h
           daa
           stosb
           ret

[Edwin Knoppert]

Wow, and i thought i had a fast conversion.. using a similar table as MCM describes (byte ptr for/next)
It took: 6.188 secs



Will investigate the asm version, the last asm code, i am not able to implement that since i don't know to interact between two languages.
I can only read asm somewhat.
Can't tell if that part would be faster.

PS, i don't see seperate output string.
I would like to copy an original dynamic string (using ptr and length) to a 2nd predimensioned dynamic string (also ptr).

[John Gleason]

Edwin, here it is in a function. I tested it at about 11x-12x faster.

#COMPILE EXE
#DIM ALL
%STRSIZE = 20000000

FUNCTION PBMAIN () AS LONG
   LOCAL wrdVar AS WORD, ii AS LONG, hexStr AS STRING
   LOCAL convStrPtr AS WORD PTR, byteStrIn, convStrOut, convStr2, cErr AS STRING, t, t2, t3 AS SINGLE
   LOCAL byteStrPtr AS BYTE PTR, inByte AS BYTE, convStrPtr2 AS STRING PTR * 2

   'byteStrIn can be any string length that will fit into memory concurrent
   'with its twice as long converted string.
   byteStrIn = SPACE$(%STRSIZE)

   'put random bytes into the byteStrIn, which can hold any byte value (0-255).
   FOR ii = 1 TO %STRSIZE
      ASC(byteStrIn, ii) = RND(0, 255)
   NEXT


   t = TIMER

   convStrOut = convertStrToHex(byteStrIn)

   t2 = TIMER

   convStr2 = convStrOut
   byteStrPtr = STRPTR(byteStrIn)
   convStrOut = SPACE$(2 * LEN(byteStrIn)) 'make converted string 2x longer than the input string
   convStrPtr2 = STRPTR(convStrOut)

   FOR ii = 0 TO LEN(byteStrIn) - 1

      @convStrPtr2 = HEX$(@byteStrPtr, 2)
      INCR byteStrPtr
      INCR convStrPtr2

   NEXT
   t3 = TIMER
   IF convStr2 <> convStrOut THEN cErr = "oops, there is an error"
   ? "asm took " & STR$(t2 - t, 4) & $CRLF & _
     "hex took " & STR$(t3 - t2, 4) & " so asm was" & _
      STR$((t3 - t2) / (t2 - t), 4) & " times faster" & $CRLF & cErr
END FUNCTION

FUNCTION convertStrToHex(byteStrIn AS STRING) AS STRING
   LOCAL convStrOut AS STRING
   LOCAL byteStrPtr, convStrPtr AS LONG
   REGISTER ii AS LONG

   convStrOut = SPACE$(2 * LEN(byteStrIn)) 'make converted string 2x longer than the input string

   byteStrPtr = STRPTR(byteStrIn)
   convStrPtr = STRPTR(convStrOut)

   FOR ii = 0 TO LEN(byteStrIn) - 1

      !mov edx, byteStrPtr
      !mov ecx, ii
      [COLOR="Red"]!movzx eax, byte ptr[edx+ecx][/COLOR]
      !call Bin8toHex
      !mov eax, convStrPtr
      !mov ecx, ii
      !mov [eax+ecx*2], dx

   NEXT

   FUNCTION = convStrOut
   EXIT FUNCTION

   Bin8toHex:
        !push    eax
        !ror     al, 4
        !call    Bin8a
        !mov     dl, dh
        !pop     eax
        !call    Bin8a
        !ret
    Bin8a:
        !and     al,&b00001111
        !add     al,&h90
        !daa
        !adc     al,&h40
        !daa
        !mov     dh, al
        !ret

END FUNCTION

[Edwin Knoppert]

I tested the earlier posted code today on Windows98, while i didn't test the actual result, the original code did not finish for some reason.

I used win98SE in a virtual pc with maybe using not enough ram?
A space of 40 000 000 is only 40MB and should work imo.
i tested with smaller sizes (afaik 4MB) and that worked.

My question in short is, is the assembly code ok to use on any Windows XP computer and up?
Win98 is not important but if you have an answer for that version as well?

Thanks for the new code, i'll test it soon.

[John Gleason]

I tested it only on Win 98, but yes, it should work on any platform. It's not doing anything at all unusual that I know of. It's self testing--that is, assuming my all-PB code is correct. Feel free to hammer on the code, because the more testing the better.

btw, I remove the test code for my timings.

[Edwin Knoppert]

Just a thought, why not move the asm code in the loop?
It saves two calls and a ret imo.
and maybe even the push and a pop?

[John Gleason]

why not move the asm code in the loop?

Indeed, it looks like 5%+ faster. Furthermore, you could make the two calls inline too for maybe a few less ticks.

FUNCTION convertStrToHex(byteStrIn AS STRING) AS STRING
   LOCAL convStrOut AS STRING
   LOCAL byteStrPtr, convStrPtr AS LONG
   REGISTER ii AS LONG

   convStrOut = SPACE$(2 * LEN(byteStrIn)) 'make converted string 2x longer than the input string

   byteStrPtr = STRPTR(byteStrIn)
   convStrPtr = STRPTR(convStrOut)

   FOR ii = 0 TO LEN(byteStrIn) - 1

        !mov     edx, byteStrPtr
        !mov     ecx, ii
        !movzx   eax, byte ptr[edx+ecx]
'  here was the original Bin8toHex start point
        !push    eax
        !ror     al, 4
        !call    Bin8a
        !mov     dl, dh
        !pop     eax
        !call    Bin8a
        !mov     eax, convStrPtr
        !mov     ecx, ii
        !mov     [eax+ecx*2], dx
   NEXT

   FUNCTION = convStrOut
   EXIT FUNCTION
   
    Bin8a:
        !and     al,&b00001111
        !add     al,&h90
        !daa
        !adc     al,&h40
        !daa
        !mov     dh, al
        !ret

END FUNCTION

[John Gleason]

Well, since it could be done inline, I did it. It showed another maybe 8-10% boost.

FUNCTION convertStrToHex(byteStrIn AS STRING) AS STRING
   LOCAL hexStrOut AS STRING
   LOCAL byteStrPtr, hexStrPtr AS LONG
   REGISTER ii AS LONG

   hexStrOut = SPACE$(2 * LEN(byteStrIn)) 'make converted string 2x longer than the input string

        !mov     eax, byteStrIn
        !mov     edx, hexStrOut
        !mov     ecx, [eax]        ;dereference byteStrIn
        !mov     hexStrPtr, edx    ;STRPTR(hexStrOut)
        !mov     byteStrPtr, ecx   ;STRPTR(byteStrIn)

   FOR ii = 0 TO LEN(byteStrIn) - 1

        !mov     edx, byteStrPtr
        !mov     ecx, ii
        !movzx   eax, byte ptr[edx+ecx]
'  here was the original Bin8toHex start point
        !push    eax
        !ror     al, 4

'  here is inline call to original Bin8a
        !and     al,&b00001111
        !add     al,&h90
        !daa
        !adc     al,&h40
        !daa
        !mov     dl, al
        !pop     eax

'  here is inline 2nd call to original Bin8a
        !and     al,&b00001111
        !add     al,&h90
        !daa
        !adc     al,&h40
        !daa
        !mov     dh, al

        !mov     eax, hexStrPtr
        !mov     ecx, ii
        !mov     [eax+ecx*2], dx
   NEXT

   FUNCTION = hexStrOut

END FUNCTION

[Edwin Knoppert]

Still havent tested the final output but i have increased the ram for the win98 VPC and does 40MB in 0.992 seconds

On my normal XP in 0.325.
(Wasn't it faster yesterday??)

[John Gleason]

One more method: a lookup table. Its disadvantage is that on first call, it may be slower because it needs to make the lookup table, but overall it will likely be quite a bit faster.

FUNCTION convertStrToHexL(byteStrIn AS STRING) AS STRING
   LOCAL hexStrOut AS STRING
   LOCAL byteStrPtr, hexStrPtr AS LONG
   STATIC oneTime, hexLookupPtr AS LONG
   REGISTER ii AS LONG

   IF oneTime = 0 THEN
      oneTime = 1
      DIM hexLookupTable(255) AS STATIC WORD
      FOR ii = 0 TO 255
         hexLookupTable(ii) = CVWRD(HEX$(ii, 2))
      NEXT
      hexLookupPtr = VARPTR(hexLookupTable(0))
   END IF
         
   hexStrOut = SPACE$(2 * LEN(byteStrIn)) 'make converted string 2x longer than the input string

        !mov     eax, byteStrIn
        !mov     edx, hexStrOut
        !mov     ecx, [eax]        ;dereference byteStrIn
        !mov     hexStrPtr, edx    ;STRPTR(hexStrOut)
        !mov     byteStrPtr, ecx   ;STRPTR(byteStrIn)

   FOR ii = 0 TO LEN(byteStrIn) - 1

        !mov     edx, byteStrPtr
        !mov     ecx, ii
        !movzx   eax, byte ptr[edx+ecx]
        
        !mov     edx, hexLookupPtr
        !movzx   edx, word ptr[edx+eax*2]

        !mov     eax, hexStrPtr
        !mov     [eax+ecx*2], dx
   NEXT

   FUNCTION = hexStrOut

END FUNCTION

[John Gleason]

I pulled out a few more stops with the code, and I think found a bug in the docs too during testing.

This LONG function speeds up significantly over the above STRING function, ~60% in my testing, by passing 2 string parameters to it: the in and out strings. Probably there is less string manipulation in the LONG function, which might explain the speed increase.

You don't have to calculate the size of the output string, so the function is just as easy to use as the string version of the function. The translation table is now built in, so there is no speed penalty on its first call.

'it can be called eg.
      LOCAL byteStrIn, hexStrOut as string
      convertStrToHexL2 byteStrIn, hexStrOut

FUNCTION convertStrToHexL2(byteStrIn AS STRING, hexStrOut AS STRING) AS LONG
   LOCAL byteStrPtr, hexStrPtr AS LONG
   REGISTER ii AS LONG

!jmp endTable
hexLookupTable:
   !db 48,48,48,49,48,50,48,51,48,52,48,53,48,54,48,55,48,56,48,57,48,65,48,66,48,67,48,68,48,69,48,70,49,48
   !db 49,49,49,50,49,51,49,52,49,53,49,54,49,55,49,56,49,57,49,65,49,66,49,67,49,68,49,69,49,70,50,48
   !db 50,49,50,50,50,51,50,52,50,53,50,54,50,55,50,56,50,57,50,65,50,66,50,67,50,68,50,69,50,70,51,48
   !db 51,49,51,50,51,51,51,52,51,53,51,54,51,55,51,56,51,57,51,65,51,66,51,67,51,68,51,69,51,70,52,48
   !db 52,49,52,50,52,51,52,52,52,53,52,54,52,55,52,56,52,57,52,65,52,66,52,67,52,68,52,69,52,70,53,48
   !db 53,49,53,50,53,51,53,52,53,53,53,54,53,55,53,56,53,57,53,65,53,66,53,67,53,68,53,69,53,70,54,48
   !db 54,49,54,50,54,51,54,52,54,53,54,54,54,55,54,56,54,57,54,65,54,66,54,67,54,68,54,69,54,70,55,48
   !db 55,49,55,50,55,51,55,52,55,53,55,54,55,55,55,56,55,57,55,65,55,66,55,67,55,68,55,69,55,70,56,48
   !db 56,49,56,50,56,51,56,52,56,53,56,54,56,55,56,56,56,57,56,65,56,66,56,67,56,68,56,69,56,70,57,48
   !db 57,49,57,50,57,51,57,52,57,53,57,54,57,55,57,56,57,57,57,65,57,66,57,67,57,68,57,69,57,70,65,48
   !db 65,49,65,50,65,51,65,52,65,53,65,54,65,55,65,56,65,57,65,65,65,66,65,67,65,68,65,69,65,70,66,48
   !db 66,49,66,50,66,51,66,52,66,53,66,54,66,55,66,56,66,57,66,65,66,66,66,67,66,68,66,69,66,70,67,48
   !db 67,49,67,50,67,51,67,52,67,53,67,54,67,55,67,56,67,57,67,65,67,66,67,67,67,68,67,69,67,70,68,48
   !db 68,49,68,50,68,51,68,52,68,53,68,54,68,55,68,56,68,57,68,65,68,66,68,67,68,68,68,69,68,70,69,48
   !db 69,49,69,50,69,51,69,52,69,53,69,54,69,55,69,56,69,57,69,65,69,66,69,67,69,68,69,69,69,70,70,48
   !db 70,49,70,50,70,51,70,52,70,53,70,54,70,55,70,56,70,57,70,65,70,66,70,67,70,68,70,69,70,70
endTable:

   hexStrOut = SPACE$(2 * LEN(byteStrIn)) 'make converted string 2x longer than the input string

        !mov     eax, byteStrIn
        !mov     edx, hexStrOut
        !mov     ecx, [eax]        ;dereference byteStrIn
        !mov     edx, [edx]        ;dereference hexStrOut
        !mov     byteStrPtr, ecx   ;STRPTR(byteStrIn)
        !mov     hexStrPtr, edx    ;STRPTR(hexStrOut)

   FOR ii = 0 TO LEN(byteStrIn) - 1

        !mov     edx, byteStrPtr
        !mov     ecx, ii
        !movzx   eax, byte ptr[edx+ecx]   ;get byte in

        !lea     edx, hexLookupTable      ;Ptr to hex conversion table
        !movzx   edx, word ptr[edx+eax*2]

        !mov     eax, hexStrPtr
        !mov     [eax+ecx*2], dx          ;2 hex chars out
   NEXT

END FUNCTION

The bug I mentioned from the docs is this:

To display a Quad-integer in hex format, use the following technique:

DIM q AS QUAD, r AS STRING

q = &H0ABCEF0EE1234567F&&

r = HEX$(HI(LONG, q)) + HEX$(LO(DWORD, q))

The one line needs to be changed to:

r = HEX$(HI(LONG, q)) + HEX$(LO(DWORD, q), 8)

because it drops needed leading zeros from the LO portion of the quad.

If this has been corrected in the new .02 update from this week, whoopsie! never mind.

[Edwin Knoppert]

I am not so happy modifying var's addresses, if you say it's ok..?

--

You may consider an asm do:loop instead if the for/next.
Can you bring the table-in-mem back? or does it bring a speed-penalty?

[John Gleason]

I am not so happy modifying var's addresses, if you say it's ok..?

If you have already filled hexStrOut with data and don't want it erased, then it's not ok, this new version will not do for you. But, if you have just declared hexStrOut normally, eg. LOCAL hexStrOut AS STRING, and have not yet used it for anything, or have used it and no longer need any of it, then the new function will work fine, plus be faster.

--
You may consider an asm do:loop instead if the for/next.
Can you bring the table-in-mem back? or does it bring a speed-penalty?

Probably no speed change will occur with do:loop instead of the for/next. It's closing in now I think to pretty good optimization.

I can bring the table-in-mem back with little or no speed penality I believe. I'll post it soon.

[Edwin Knoppert]

I thought that using a long for the Strptr() would do was my point actually.
You have used some asm which i do'nt understand and thought it swapped the addresses.

Side note: i'll convert this function to a pmem+len, pmemout function, it shouldn't care about the memory type.
I said using dynamic strings to avoid discussions like using asciiz or whatever.

Function ToHex(byval pMen as long, byval nSize as long, Byval pmemout as long ) As long


--

I said do:loop but i meant a counter actually, asm code of course..