2 addressing modes – Texas Instruments MSP430x1xx User Manual

Page 71

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Addressing Modes

5-7

16-Bit CPU

5.2

Addressing Modes

All seven addressing modes for the source operand and all four addressing
modes for the destination operand can address the complete address space.
The bit numbers in Table 5–4 describe the contents of the As and Ad mode bits.
See Section 5.3 for a description of the source address As and the destination
address Ad bits.

Table 5–4. Source/Destination Operand Addressing Modes

As/Ad

Addressing Mode

Syntax

Description

00/0

Register mode

Rn

Register contents are operand

01/1

Indexed mode

X(Rn)

(Rn + X) points to the operand

X is stored in the next word

01/1

Symbolic mode

ADDR

(PC + X) points to the operand

X is stored in the next word.
Indexed mode X(PC) is used.

01/1

Absolute mode

&ADDR

The word following the instruction
contains the absolute address.

10/–

Indirect register
mode

@Rn

Rn is used as a pointer to the
operand.

11/–

Indirect
autoincrement

@Rn+

Rn is used as a pointer to the
operand. Rn is incremented
afterwards.

11/–

Immediate mode

#N

The word following the instruction
contains the immediate constant
N. Indirect autoincrement mode
@PC+ is used.

The seven addressing modes are explained in detail in the following sections.
Most of the examples show the same addressing mode for the source and
destination, but any valid combination of source and destination addressing
modes is possible in an instruction.

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