PrintHex16 size optimizations?

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bitshifter

Joined: 04 Dec 2007
Posts: 796
Location: Massachusetts, USA

bitshifter 20 Mar 2010, 12:54

I am trying to make 16bit hex output very small.
So far i have eliminated hex-char table for size.
Maybe you have a trick for very small version?
This is intended for a 16bit size critical demo.

My code so far (22 bytes)

Code:

        ; ES:DI -> Video memory
        ; DX = Register to print
        ; AH = Color attribute

PrintHex16:
        mov     cx,4
.cycle: rol     dx,4
        mov     al,dl
        and     al,0Fh
        cmp     al,9
        jle     .nohex
        add     al,'A'-'9'-1
.nohex: add     al,'0'
        stosw
        loop    .cycle
        ret

        ; Trashed AL,CX,DX,DI

_________________
Coding a 3D game engine with fasm is like trying to eat an elephant,
you just have to keep focused and take it one 'byte' at a time.

20 Mar 2010, 12:54

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20415
Location: In your JS exploiting you and your system

revolution 20 Mar 2010, 13:05

19 bytes:

Code:

PrintHex16:
     mov     cx,4
.cycle: rol dx,4
        mov     al,dl
       and     al,0Fh
      cmp     al,10
       sbb     al,069h
     das
 stosw
       loop    .cycle
      ret

20 Mar 2010, 13:05

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8356
Location: Kraków, Poland

Tomasz Grysztar 20 Mar 2010, 13:07

The SBB+DAS trick is already widely known on this forum, you can strip a few bytes with it.

EDIT: Oh, revolution was first with it. Smile

20 Mar 2010, 13:07

bitshifter

Joined: 04 Dec 2007
Posts: 796
Location: Massachusetts, USA

bitshifter 20 Mar 2010, 13:24

Cool, i was unaware of this method (i searched 4 a while)
I have been searching/pondering this for about 2 hours.
I had SBB in my back pocket but wasnt enough by itself.
I figured i could spend the rest of my life theorizing it
or i could just ask someone with more brains than me.
Hey, at least im only a few bytes behind the times, right?
Now i go read about this DAS instruction.
Thanks for help Smile

20 Mar 2010, 13:24

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20415
Location: In your JS exploiting you and your system

revolution 20 Mar 2010, 13:34

I pwned Tomasz. Twisted Evil

20 Mar 2010, 13:34

DOS386

Joined: 08 Dec 2006
Posts: 1903

DOS386 20 Mar 2010, 13:55

revolution wrote:

19 bytes:

Code:

PrintHex16:
.cycle: rol   dx,4

NOT 8086-compatible, better code: http://board.flatassembler.net/topic.php?t=9738 http://www.bttr-software.de/forum/forum_entry.php?id=6631

Quote:

I pwned Tomasz.

I pwned revolution.

20 Mar 2010, 13:55

Fanael

Joined: 03 Jul 2009
Posts: 168

Fanael 21 Mar 2010, 08:35

DOS386 wrote:

NOT 8086-compatible

Is there anyone who still uses 8086?

21 Mar 2010, 08:35

rugxulo

Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)

rugxulo 23 Mar 2010, 15:40

Fanael wrote:

DOS386 wrote:
NOT 8086-compatible
Is there anyone who still uses 8086?

23 Mar 2010, 15:40

DOS386

Joined: 08 Dec 2006
Posts: 1903

DOS386 10 May 2010, 09:50

WARNING: old thread

rugxulo wrote:

Wolfenstein 3D for 8086 url=http://www.lootube.com/watch?v=5f7gW5X24ao

All what we need is a thing allowing to watch LooTubeFlashCrap on 8086 Wink

10 May 2010, 09:50

edemko

Joined: 18 Jul 2009
Posts: 549

edemko 29 Jul 2010, 17:11

Code:

        ;;dedicated to DOS386 a funny man
        and     al,$0f   ;prepare for DAA
        add     al,'0'   ;$00..$0f->'0'..'?' -> (AL<$100)&(CF=0) -> DAA.2nd_if with +$60 skept
        daa              ;if (AL and $0f > 9)|(AF=1(never TRUE)){ADD AL,$06}
        cmp     al,'A'-1 ;if $06 was not added
        sbb     al,-1    ;do nothing
        ;;               ;hope more polite then DAS

29 Jul 2010, 17:11

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