Q47504: Some Instructions May Require Enabling of Instruction Set

Article: Q47504
Product(s): Microsoft Macro Assembler
Version(s): MS-DOS:5.0,5.1,5.1a,6.0,6.0a,6.0b
Operating System(s): 
Keyword(s): 
Last Modified: 06-MAY-2001

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The information in this article applies to:

- Microsoft Macro Assembler (MASM), versions 5.0, 5.1, 5.1a, 6.0, 6.0a, 6.0b 
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SUMMARY
=======

Using an instruction that requires a 80186, 80286, or 80386 processor may cause
the Microsoft Macro Assembler (MASM) 5.1 to generate the one of the following
errors:

  A2066: Must have instruction after prefix.

  A2105: Expected: instruction, directive, or label

and MASM 6.0 to generate the following error:

  A2085: instruction or register not accepted in current CPU mode

The error occurs because the default assembly mode is 8086. The .186, .286,
.286p, .386, or .386p directive must be placed in the source code prior to any
instructions that require those modes.

In addition, MASM 6.0 supports 80486 instructions.

MORE INFORMATION
================

The following information is taken from page 621 of the "Microsoft Macro
Assembler Programmer's Guide" for MASM 6.0

80186 Processor Instructions

  BOUND        INSW         OUTSW
  ENTER        LEAVE        POPA
  INS          OUTS         PUSHA
  INSB         OUTSB        PUSHW*

80286 Processor Instructions

  ARPL         SIDT         VERR
  LAR          SLDT         VERW
  LSL          SMSW
  SGDT         STR

80286 and 80386 Privileged-Mode Instructions

  CLTS         LIDT         LMSW
  LGDT         LLDT         LTR

80386 Processor Instructions

  BSF          LSS          SETNAE
  BSR          MOVSD        SETNB
  BT           MOVSX        SETNBE
  BTC          MOVZX        SETNC
  BTR          OUTSD        SETNE
  BTS          POPAD        SETNG
  CDQ          POPFD        SETNGE
  CMPSD        PUSHAD       SETNL
  CWDE         PUSHD*       SETNLE
  INSD         PUSHFD       SETNO
  IRETD        SCASD        SETNP
  IRETDF*      SETA         SETNS
  IRETF*       SETAE        SETNZ
  JECXZ        SETB         SETO
  LFS          SETBE        SETP
  LGS          SETC         SETPE
  LODSD        SETE         SETPO
  LOOPD*       SETG         SETS
  LOOPED*      SETGE        SETZ
  LOOPNED*     SETL         SHLD
  LOOPNZD*     SETLE        SHRD
  LOOPZD*      SETNA        STOSD

80486 Processor Instructions

  BSWAP*       INVD*        WBINVD*
  CMPXCHG*     INVLPG*      XADD*

  * New to MASM 6.0

Additional query words: kbinf 5.00 5.10 5.10a 6.00 6.00a 6.00b

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Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM510 kbMASM600 kbMASM500 kbMASM600a kbMASM510a kbMASM600b
Version           : MS-DOS:5.0,5.1,5.1a,6.0,6.0a,6.0b

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