3.4.2 Logic and arithmetic operations
The instructions of the logic operations are: and, not, or and xor. These
work on the bits of their operators.
To verify the result of the operations we turn to the cmp and test
instructions.
The instructions used for the algebraic operations are: to add, to
subtract sub, to multiply mul and to divide div.
Almost all the comparison instructions are based on the information
contained in the flag register. Normally the flags of this register which
can be directly handled by the programmer are the data direction flag DF,
used to define the operations about chains. Another one which can also be
handled is the IF flag by means of the sti and cli instructions, to activate
and deactivate the interruptions.
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