dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 59

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

3.3.1.1
The syntax and sequence for all move instructions on the DSP56800E is as follows:
and destination are separated by a comma, with no spaces either before or after the comma, as shown in
Example 3-1.
3.3.1.2
Each instruction that accesses memory must specify the particular memory address space (data or
program) that is being referenced. Addresses in memory should be prefixed with either X: to indicate the
data memory space or with P: to indicate the program memory space. Table 3-4 shows the address space
prefixes and their use.
To avoid confusion, specify all addresses with one of these prefixes. Instructions that do not have this
requirement include jump and branch instructions, whose target addresses always access program memory.
3.3.1.3
The size of data accessed from memory is indicated by a suffix:
The difference between the two byte accesses is explained in Section 3.5, “Memory Access and Pointers.”
3.3.2
Instructions access data memory in one of three ways: using a MOVE instruction with a parameter that
refers to data memory, using an arithmetic instruction that has a parameter in data memory, or using a
bitfield manipulation instruction.
3.3.2.1
The DSP56800E provides separate move instructions to ensure that the destination register is zero
extended or sign extended, as appropriate. For unsigned register loads from memory, the letter “U”
immediately follows the “MOVE” portion of the instruction. Unsigned moves are important only when a
register is being written and are not required when a register is being read.
Freescale Semiconductor
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“.W” suffix—indicates word memory accesses
“.L” suffix—indicates long memory accesses
“.B” suffix—indicates byte memory accesses
“.BP” suffix—indicates byte memory accesses
Instructions That Access Data Memory
MOVE.W
Ordering Source and Destination
Memory Space Syntax
Specifying Data Size
Signed and Unsigned Moves
Example 3-1. Demonstrating Source and Destination Operands
X0,R3
Symbol
P:
X:
Table 3-4. Memory Space Symbols
Data Types and Addressing Modes
Examples
X:$C000
P:(R2)+
X:(R0)
; X0 is the source operand
; R3 is the destination operand
Program memory access
Data memory access
Description
Memory Access Overview
SRC,DST
. The source
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