::::::.
::/ \:::.
:/___\::::.
/|    \:::::.
:|   _/\::::::.
:| _|\  \:::::::.
:::\_____\::::::::.
::::::::::::::::::::.
::::::::::::::::::::::.


Reader Responses to Issue Challenges



Issue 1 Challenge: Program that reads its own command line (11 bytes) 

        mov     esi,081h
DoItAgain:
        lodsb
        int     029h    ;Fast char writing!
        xor     al,0dh
        jnz     DoItAgain
        ret
...Sexus Sexy
Issue 2 Challenge: Smallest Possible PE program that reads its own command line 

include win32api.inc

.386p
.model flat,STDCALL

extrn           GetCommandLineA                 :proc
extrn           MessageBoxA                     :proc
extrn            ExitProcess                    :proc

.data
        db      013h
.code

Main:                   
                mov     eax,EndMain-Main-5              ;Real size of program!  
                call    GetCommandLineA
                push    MB_OK
                call    @1
                db      "GetCommandLine",0
@1:
                push    eax
                push    NULL
                call    MessageBoxA
                call    ExitProcess
EndMain:
end             Main
...Sexus Sexy
Issue 3 Challenge: Convert an ASCII representation of a hexadecimal digit to binary (6 bytes)

I'm not quite sure what is meant by that, I will guess that it means convert an ASCII byte into its hex equivalent. For '0'-'9' and 'A'-'F' (but not 'a'-'f') the following works, assuming the ASCII byte is AL. This uses undocumented forms of AAM and AAD which may not assemble or run everywhere: 

     SUB AL, 30h
     AAM 10h         ; db D4h, 10h
     AAD 09h         ; db D5h, 09h
...tinara