Q39525: ARPL (Protected Mode Only) Produces Incorrect Code

Article: Q39525
Product(s): See article
Version(s): 5.00   | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | buglist5.10 | mspl13_masm
Last Modified: 12-JAN-1989

MASM Versions 5.10 and earlier have the register operands reversed for
ARPL as follows:

   ARPL AX, CX

It should have an operand byte of C1 instead of C8.

Microsoft has confirmed this to be a problem in Version 5.10. We are
researching this problem and will post new information as it becomes
available.

The following code demonstrates this problem and should assemble to
"63 C1":

dosseg
.model small
.386p
.code

start:
        ARPL AX, CX
        end start

.........................................................................
       1                                dosseg
       2                                .model small
       3                                assume cs:@code,ds:@data,ss:@data
       4                                .386p
       5                                .code
       6 0000                           _TEXT segment 'CODE'
       7
       8 0000                           start:
       9 0000  63 C8                            ARPL AX, CX
      10                                        end start
      11 0002                           @CurSeg ends
..........................................................................

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