RM5231A-350-H PMC-Sierra Inc, RM5231A-350-H Datasheet - Page 12

• Manufacturer Part Number: RM5231A-350-H
• Description: RM5231A Microprocessor with 32-Bit System Bus Data Sheet Preliminary
• Manufacturer: PMC-Sierra Inc

Proprietary and Confidential to PMC-Sierra, Inc and for its Customer’s Internal Use
Document ID: PMC-2002174, Issue 2
3
3.1
3.2
3.3
Hardware Overview
The RM5231A offers a high-level of integration targeted at high-performance embedded
applications. The key elements of the RM5231A are briefly described below.
Superscalar Dispatch
The RM5231A has an asymmetric superscalar dispatch unit which allows it to issue an integer
instruction and a floating-point computation instruction simultaneously. Integer instructions
include alu, branch, load/store, and floating-point load/store, while floating-point computation
instructions include floating-point add, subtract, combined multiply-add, and converts. In
combination with its high-throughput fully pipelined floating-point execution unit, the superscalar
capability of the RM5231A provides unparalleled price/performance in computationally intensive
embedded applications.
CPU Registers
The RM5231A contains 32 general purpose registers, two special purpose registers for integer
multiplication and division, a program counter, and no condition code bits. Figure 2 shows the user
visible state.
Figure 2 CPU Registers
Pipeline
For integer operations, loads, stores, and other non-floating-point operations, the RM5231A uses
the 5-stage pipeline. In addition to the integer pipeline, the RM5231A uses an extended 7-stage
pipeline for floating-point operations.
Figure 3 shows the RM5231A integer pipeline. As illustrated in the figure, up to five integer
instructions can be executing simultaneously.
General Purpose Registers
63
0
r1
r2
•
•
•
•
r29
r30
r31
0
RM5231A™ Microprocessor with 32-Bit System Bus Data Sheet
Multiply/Divide Registers
63
HI
63
LO
Program Counter
63
PC
0
0
0
Preliminary
11