Function:                                   

This instruction regularly performs the following action:
  - unpacked BCD in AX   example (AX = 0104h)
  - AL = AH * 10d + AL   (AL = 0eh )
  - AH = 00              (AH = 00h )

The normal opcode decodes as follows: d5,0a
The instruction itself is an instruction plus operand. By replacing the
second byte with any number in the range 00 - ff you can build your own
instruction AAD for various number systems in those ranges. For example
by coding d5,10 you achieve an instruction that performs:

  - AL = AH * 16d + AL.
  - AH = 00

This feature of Intel's chips can be used to determine whether there is
a true Intel CPU installed in a system.

(NEC difference supplied by Anthony Naggs)




AAM   Adjust After BCD Multiplication
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