5-3
DATA TYPES AND ADDRESSING MODES
5.2.NUMERIC, POINTER, BIT FIELD, AND STRING DATA TYPES
Although bytes, words, and doublewords are the fundamental data types of the IA, some instruc-
tions support additional interpretations of these data types to allow operations to be performed
on numeric data types (signed and unsigned integers and BCD integers). Refer to Figure 5-4.
Also, some instructions recognize and operate on additional pointer, bit field, and string data
types. The following sections describe these additional data types.
5.2.1.Integers
Integers are signed binary numbers held in a byte, word, or doubleword. All operations assume
a twos complement representation. The sign bit is located in bit 7 in a byte integer, bit 15 in a
word integer, and bit 31 in a doubleword integer. The sign bit is set for negative integers and
cleared for positive integers and zero. Integer values range from 128 to +127 for a byte integer,
from 32,768 to +32,767 for a word integer, and from 2
31
to +2
31
1 for a doubleword integer.
