ID Number: Q75178
5.10 5.10a 6.00 | 5.10 5.10a 6.00
MS-DOS | OS/2
buglist5.10 buglist5.01a buglist6.00 fixlist6.00a
Summary:
PROBLEM ID: MSM9108002
SYMPTOMS
When the ASSUME directive uses the SEG operator on a communal far
data item in the Microsoft Macro Assembler (MASM) versions 5.1,
5.1a, and 6.0, it may generate an error incorrectly. The statement
"cmp dog, 0" in the sample code below incorrectly generates the
following message when assembled with MASM 5.1 or 5.1a:
A2068: Cannot address with segment register
MASM 6.0 incorrectly generates the following message:
A2074: cannot access label through segment registers
RESOLUTION
The following workarounds may be used to eliminate the error
messages:
1. Use the segment name instead of the SEG operator on a label, such
as "ASSUME ds:FAR_DATA" instead of "ASSUME ds:SEG dog".
2. Specify the segment register along with the label, such as
"cmp ds:dog, 0" instead of "cmp dog, 0".
3. With MASM 6.0, specify that the communal data is far, such as
"COMM FAR dog:BYTE instead of "COMM dog:BYTE".
STATUS
Microsoft has confirmed this to be a problem in MASM versions 5.1,
5.1a, and 6.0. This problem was corrected in MASM version 6.0a.
More Information:
Sample Code
-----------
; Assemble options needed: none
.MODEL LARGE, C
.FARDATA
COMM dog:BYTE
.CODE
cat PROC
ASSUME ds:SEG dog
mov ax, SEG dog
mov ds, ax
cmp dog, 0
ret
cat ENDP
END