Friday May 26 1995 08:14, Bill Grimsley wrote to Paul Edwards:

 BG> Exception 6: Your computer has attempted to execute an invalid
 BG> instruction due to an error in one of your programs, a conflict
 BG> between two programs, or a conflict between a program and a hardware
 BG> device.

--------C-06---------------------------------
INT 06 C - CPU-generated (80286+) - INVALID OPCODE
Desc:   this interrupt is generated when the CPU attempts to execute an
          invalid opcode (most protected-mode instructions are considered
          invalid in real mode) or a BOUND, LDS, LES, or LIDT instruction
          which specifies a register rather than a memory address
Notes:  return address points to beginning of invalid instruction
        with proper programming, this interrupt may be used to emulate
          instructions which do not exist; many 386 BIOSes emulate the 80286
          undocumented LOADALL instruction which was removed from the 80386+
        generated by the 80386+ when the LOCK prefix is used with instructions
          other than BTS, BTR, BTC, XCHG, XADD (486), CMPXCHG (486), INC, DEC,
          NOT, NEG, ADD, ADC, SUB, SBB, AND, OR, or XOR, or any instruction
          not accessing memory.
SeeAlso: INT 0C"CPU",INT 0D"CPU"

 BG>          Exception #6 at 12C0:72DE, error code: 0000
 BG>          AX=4E84 BX=0000 CX=0007 DX=634D SI=05FE DI=0610 BP=FFFF
 BG>          DS=0298 ES=4E84 SS=0606 SP=4D72 Flags=3046
 BG>          Instruction: 63 61 80 00 00 00 E4 B2 00 00 74 00 36 35 31
    _______________________/
   /
636180         arpl   [bx+di-80],sp
0000           add    [bx+si],al
00E4           add    ah,ah
B200           mov    dl,00
007400         add    [si],dh

    No idea what ARPL does:

*ARPL ew,rw     Adjust RPL of EA word not smaller than RPL of rw

    Whatever that means, righto. The rest looks reasonably OK. ARPL may not
be supported on Noel's machine. I would find out *exactly* what type of
processor he has, and who made it.

    ARPL is a 186+ instruction, it may be unavailable in real mode. I don't
have any extra information on it.

    Get Noel to run it with HIMEM.SYS only, or no memory manager
whatsoever.. see if it still happens.

    Do you have anyone else running msged under QEMM?

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