TIP: Click on subject to list as thread! ANSI
echo: 80xxx
to: CAMERON CLARK
from: BRIAN MCCLOUD
date: 1997-06-23 06:51:00
subject: 03050000 instruction =?

CC>    I've a conflict of programs/documents.
CC>    The intel document says that 0305000 decodes to
CC>    add ax,op_mem
CC>    Turbo assembler sasy it decodes to
CC>    add ax,[di]
CC>    I decode it to the following
CC>    0000 0011:0000 0101:0000 0000:0000 0000
CC>    0000 0011    00     000  0101
CC>    (add    w)   (mod)  (ax) (ds:di)
CC>            |------------|
CC> This is using 16bit addressing with the r/m bits to decode it,
CC> the intel doc says that the ModRM bit 05h says that a 32 bit displacement
CC> follows. This would be using 32 bit addressing decoding of the r/m
CC> bits.
CC>    What in the hell tells you to use the 32 bit decoding from 05h?
CC>    Which one is in error turbor debugger or intel document?
Neither one.  They're just making different assumptions about the
segmentation.
In a Use32 segment,
030500000000 decodes as:
        ADD     EAX, [00000000h]
In a Use16 segment,
030500000000 decodes as
        ADD     AX, [DI]
        ADD     [BX+SI], AL
        ADD     [BX+SI], AL
((Cloud))
MauveCloud@juno.com
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