Operand in AAM and AAD

[Garrett]

I was just playing around with AAM and AAD and I found that it' s not possible to use an operand to convert a binary value to a any base BCD value.

So if I like to convert 0x1F to a octal BCD value, I would use the code below:

Code Select Expand


mov al, 01Fh
aam 08h


But MASM 10 doesn't seem to like the aam 08h instruction, it gives a integer error.
If I open the assembled (AAM without operand) file with OllyDbg and patch the AAM 0xA (88 0A) to AAM 0x8 (88 08), the CPU calculates the 0x1F to octal 37 correctly.

What's the reason that MASM doesn't understand the AAM / AAD with operrand?

P.S: The reason I'm playing around with this, is that I'm trying to shorten the intel instruction set reference (with SSE1-4) to a few handy papers, ordered by the purpose of the instruction. Sometimes I test the behavior of the instructions if the intel reference is unclear.

If someone has improvements to the  or wants to join me, I would be happy.

[jj2007]

This works:

Code Select Expand

mov al, 01Fh
db 0d4h, 08h ; aka aam 8


[drizz]

http://www.asmcommunity.net/board/index.php?topic=25923.msg189015#msg189015