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3.3 Addressing Modes
Seven addressing modes for the source operand and four addressing modes
for the destination operand can address the complete address space with no
exceptions. The bit numbers in Table 3−3 describe the contents of the As
(source) and Ad (destination) mode bits.
Table 3−3. Source/Destination Operand Addressing Modes
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.
Note: Use of Labels EDE, TONI, TOM, and LEO
Throughout MSP430 documentation EDE, TONI, TOM, and LEO are used
as generic labels. They are only labels. They have no special meaning.
As/Ad
Addressing Mode
00/0
Register mode
01/1
Indexed mode
01/1
Symbolic mode
01/1
Absolute mode
10/−
Indirect register
mode
11/−
Indirect
autoincrement
11/−
Immediate mode
Addressing Modes
Syntax
Description
Rn
Register contents are operand
X(Rn)
(Rn + X) points to the operand. X
is stored in the next word.
ADDR
(PC + X) points to the operand. X
is stored in the next word. Indexed
mode X(PC) is used.
&ADDR
The word following the instruction
contains the absolute address. X
is stored in the next word. Indexed
mode X(SR) is used.
@Rn
Rn is used as a pointer to the
operand.
@Rn+
Rn is used as a pointer to the
operand. Rn is incremented
afterwards by 1 for .B instructions
and by 2 for .W instructions.
#N
The word following the instruction
contains the immediate constant
N. Indirect autoincrement mode
@PC+ is used.
RISC 16-Bit CPU
3-9
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