dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 86

• Manufacturer Part Number: dsp56800e
• Description: 16-bit Digital Signal Controller Core
• Manufacturer: Freescale Semiconductor, Inc

Data Types and Addressing Modes
3.6.3.8
This addressing mode contains the 16-bit immediate displacement in the second instruction word. This
second word is treated as a signed, two’s-complement, 16-bit value except when byte pointers (MOVE.BP
and MOVEU.BP) are used, in which case the second word is zero extended. This addressing mode is
available for the move instructions. When a long 32-bit memory location is accessed, the 16-bit
displacement is left shifted 1 bit before the addition. When byte values are accessed, the displacement is
given in bytes.
Figure 3-22 demonstrates this addressing mode.
3-36
Available for: Byte (Byte and Word Pointer), Word, Long
Assembler Syntax: X:(Rn+xxxx), X:(N+xxxx), X:(SP+xxxx)
Additional Instruction Execution Cycles: 1
Additional Effective Address Program Words: 1
A
35 32 31
$0080CF
A2
Index by 16-Bit Displacement: (Rn+xxxx)
$007000
F
Figure 3-22. Address Register Indirect: Indexed by 16-Bit Displacement
R2
Indexed by 16-Bit Displacement Example:
E
15
23
Before Execution
D
X
X
A1
X Memory
$007000
Zero Extend for MOVE.BP, MOVEU.BP
C
X
X
One Extend for All Other Instructions
B
16 15
X
X
from the Instruction Word
16-Bit Immediate Value
DSP56800E Core Reference Manual
X
X
A
0
0
9
A0
+
8
7
0
A
MOVE.W A1,X:(R2+$10CF)
35 32 31
A2
$0080CF
$007000
F
R2
E
15
23
After Execution
D
E
X
A1
X Memory
$007000
C
D
X
B
16 15
C
X
Freescale Semiconductor
B
X
A
0
0
9
A0
8
7
0