XPost: comp.os.msdos.programmer, alt.lang.asm   
   From: nowhere@nospicedham.nevernet.at   
      
   On 31/12/2022 21:52, Kerr-Mudd, John wrote:   
      
   >>>> example text to unrot:   
   >>>>   
   >>>> Onebarff Znetnerg Gungpure!   
      
   >>> Now allows >1 space between the strings! (but no error checking)   
   >> Now 90 bytes, assumes that at start ax=0,bh=0 and that cx > lth of   
   >> parameters.   
   >> I think that's as small as I can manage.   
      
   > [duff code dump]   
   > I see no-one (including me,til now!) has tested it. it works under grdb   
   > because bp is 0 at start. Not in native DOS/XP cmd box though.   
      
   > Fix by using di instead of bp.   
   > ->          d 100 l5A   
   > 1637:0100 99 BF 5A 01-AA FE C0 75-FB B3 83 B0-20 89 DF F2  ..Z....u.... ...   
   > 1637:0110 AE F3 AE 89-FE 80 F2 01-74 04 88 85-5A 01 97 87  ........t...Z...   
   > 1637:0120 DE 80 3C 2D-75 08 40 3A-44 01 76 E9-46 46 AC 3C  ..<-u.@:D.v.FF.<   
   > 1637:0130 27 75 E2 BA-5A 02 31 DB-89 D6 89 F7-B9 A5 FD B4  'u..Z.1.........   
   > 1637:0140 3F CD 21 91-E3 13 BB 5A-01 51 AC D7-AA E2 FB 59  ?.!....Z.Q.....Y   
   > 1637:0150 BB 01-00 B4 40 CD-21 EB DD C3                    ....@.!...   
   > ->          q   
      
   >> Wolfgang, would you like it in asm? here it is -   
      
   :) Happy New Year!   
      
   I actually had no idea what this is supposed to do...   
   if it is something like ROT13 I dunno the required algo. but   
   code parts look suspicious as if compiled by good old BASIC.   
      
   >> ->          u 100 l5A   
   >> 1637:0100 99             cwd   
   >> 1637:0101 BF 5A 01       mov          di,015A   
   >> 1637:0104 AA             stosb   
   >> 1637:0105 FE C0          inc          al   
   >> 1637:0107 75 FB          jnz          0104   
   >> 1637:0109 B3 83          mov          bl,83   
   >> 1637:010B B0 20          mov          al,20   
   >> 1637:010D 89 DF          mov          di,bx   
   >> 1637:010F F2 AE          repnz scasb   
   >> 1637:0111 F3 AE          repz scasb   
   >> 1637:0113 89 FE          mov          si,di   
   >> 1637:0115 80 F2 01       xor          dl,01   
   >> 1637:0118 74 04          jz           011E   
   > change bp to di in the next 2 lines:   
   > ;> 1637:011A 88 86 5A 01    mov          [bp+015A],al   
   > ;> 1637:011E 95             xchg         ax,bp   
   >   
   > 1637:011A 88 85 5A 01    mov          [di+015A],al   
   > 1637:011E 97             xchg         ax,di   
   >   
   >> 1637:011F 87 DE          xchg         bx,si   
   >> 1637:0121 80 3C 2D       cmp          byte [si],2D   
   >> 1637:0124 75 08          jnz          012E   
   >> 1637:0126 40             inc          ax   
   >> 1637:0127 3A 44 01       cmp          al,[si+01]   
   >> 1637:012A 76 E9          jbe          0115   
   >> 1637:012C 46             inc          si   
   >> 1637:012D 46             inc          si   
   >> 1637:012E AC             lodsb   
   >> 1637:012F 3C 27          cmp          al,27   
   >> 1637:0131 75 E2          jnz          0115   
   >> 1637:0133 BA 5A 02       mov          dx,025A   
   >> 1637:0136 31 DB          xor          bx,bx   
   >> 1637:0138 89 D6          mov          si,dx   
   >> 1637:013A 89 F7          mov          di,si   
   >> 1637:013C B9 A5 FD       mov          cx,FDA5   
   >> 1637:013F B4 3F          mov          ah,3F   
   >> 1637:0141 CD 21          int          21   
   >> 1637:0143 91             xchg         ax,cx   
   >> 1637:0144 E3 13          jcxzw        0159   
   >> 1637:0146 BB 5A 01       mov          bx,015A   
   >> 1637:0149 51             push         cx   
   >> 1637:014A AC             lodsb   
   >> 1637:014B D7             xlat         [bx]   
   >> 1637:014C AA             stosb   
   >> 1637:014D E2 FB          loopw        014A   
   >> 1637:014F 59             pop          cx   
   >> 1637:0150 BB 01 00       mov          bx,0001   
   >> 1637:0153 B4 40          mov          ah,40   
   >> 1637:0155 CD 21          int          21   
   >> 1637:0157 EB DD          jmp          0136   
   >> 1637:0159 C3             ret   
   __   
   wolfgang   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)