dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 62

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

Data Types and Addressing Modes
3.3.5.1
The single parallel move allows an arithmetic operation and 1 memory word access to be completed with
1 instruction, in 1 clock cycle. For example, all in the same instruction, it is possible to add two numbers
while writing a value from a data ALU register to memory.
Figure 3-2 illustrates a single parallel move that uses 1 program word and executes in 1 instruction cycle.
In this example, the following events occur:
3.3.5.2
With a single instruction, in 1 instruction cycle, the dual parallel read performs an arithmetic operation and
reads two word values from data memory. For example, a dual parallel read can multiply two numbers
while reading two values from data memory to two of the data ALU registers.
Figure 3-3 illustrates a dual parallel read that also uses 1 program word and executes in 1 instruction cycle.
In this example, the following events occur:
3-12
1. Register X0 is added to the A accumulator, and the result is stored back in A.
2. The contents of the Y0 register is stored as a word in data memory at the address contained
3. When the memory move is completed, the R1 register is post-updated by the value of
1. The original contents of the X0 and Y0 registers are multiplied, and the result is added to and
2. The contents of the data memory location pointed to by the R0 register are moved into the
3. The contents of the data memory location pointed to by the R3 register are moved into the
4. After completing the memory moves, the R0 register is post-updated with the value R0+N,
in the R1 register.
R1+N.
stored in the A accumulator.
Y1 register. The size of the access is 1 memory word.
X0 register. The size of the access is 1 memory word.
and R3 is decremented.
Opcode and Operands
Single Parallel Move
Dual Parallel Read
MAC X0,Y0,A
ADD X0,A
Opcode and Operands
DSP56800E Core Reference Manual
(Uses XAB1 and CDBW)
Figure 3-2. Single Parallel Move
Figure 3-3. Dual Parallel Read
Single Parallel Move
Y0,X:(R1)+N
(Uses XAB1 and CDBR)
X:(R0)+N,Y1
Primary Read
; Example parallel move instruction
(Uses XAB2 and XDB2)
X:(R3)-,X0
Secondary Read
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