5-6
DATA TYPES AND ADDRESSING MODES
5.2.7.Floating-Point Data Types
The processors floating-point instructions recognize a set of real, integer, and BCD integer data
types. Refer to Section 7.4., Floating-Point Data Types and Formats in Chapter 7, Floating-
Point Unit for a description of FPU data types.
5.2.8.MMX Technology Data Types
IA processors that implement the Intel MMX technology recognize a set of packed 64-bit data
types. Refer to Section 8.1.2., MMX Data Types in Chapter 8, Programming with the Intel
MMX Technology for a description of the MMX data types.
5.2.9.Streaming SIMD Extensions Data Types
IA processors that implement the Intel Streaming SIMD Extensions recognize a set of 128-bit
data types. Refer to Section 9.1.2., SIMD Floating-Point Data Types in Chapter 9, Program-
ming with the Streaming SIMD Extensions for a description of the SIMD floating-point data
types.
5.3.OPERAND ADDRESSING
An IA machine-instruction acts on zero or more operands. Some operands are specified explic-
itly in an instruction and others are implicit to an instruction. An operand can be located in any
of the following places:
The instruction itself (an immediate operand).
A register.
A memory location.
An I/O port.
5.3.1.Immediate Operands
Some instructions use data encoded in the instruction itself as a source operand. These operands
are called immediate operands (or simply immediates). For example, the following ADD
instruction adds an immediate value of 14 to the contents of the EAX register:
ADD EAX, 14
All the arithmetic instructions (except the DIV and IDIV instructions) allow the source operand
to be an immediate value. The maximum value allowed for an immediate operand varies among
instructions, but can never be greater than the maximum value of an unsigned doubleword
integer (2
32
).
