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Section 4
Arithmetic and Bit
Manipulation Functions
Integer arithmetic operations and bit manipulation functions can
only be performed in Integer mode. Since these functions are
subject to carry and out-of-range conditions, an explanation of
these
conditions
precedes
the
discussion
of
the
functions
themselves.*
Floating-point decimal arithmetic and other capabilities of
Floating-Point Decimal mode are discussed in section 5, Floating-
Point Numbers.
Carry and Out-of-Range Conditions
The
execution
of certain
arithmetic
and
bit
manipulation
operations can result in a carry and/or an out-of-range condition.
These conditions set flags (that may be tested) and display
annunciators (for visual indication). The definitions for "carry"
and "out-of-range" depend on the particular function executed.
Section 3, under Flags (page 36), explains how to manually set and
clear these (and other) flags.
Flag 4: Carry (C)
The shifting, rotating, and arithmetic operations listed below will
set or clear flag 4 and the C annunciator whenever they are
performed in Integer mode. Flag 4, the carry flag, is set if the carry
bitis 1, and cleared if the carry bit is 0.
[(+](carry)
RLC
RLCn
(-] (borrow)
(:)(remainder # 0)
RRC
RRCn
(remainder # 0)
(remainder # 0)
(These functions are described later in this section.)
* Appendix A includes a table of the relevant functions and how they affect the carry and
out-of-range flags.
39
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