ACT5230
32-Bit Superscaler Microprocessor
Features
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Full militarized QED RM5230 microprocessor
Dual Issue superscalar microprocessor - can issue one
integer and one floating-point instruction per cycle
133 and 150 MHz operating frequency – Consult
Factory for latest speeds
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228 Dhrystone2.1 MIPS
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SPECInt95 4.2 SPECfp95 4.5
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100,
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High-performance floating point unit
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Single
cycle repeat rate for common single precision
operations and some double precision operations
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Two cycle repeat rate for double precision multiply and
double precision combined multiply-add operations
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Single cycle repeat rate for single precision combined
multiply-add operation
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System interface optomized for embedded
applications
system interface lowers total system cost with up to
87.5 MHz operating frequency
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High performance write protocols maximize uncached
write bandwidth
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Operates at processor clock divisors 2 through 8
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5V tolerant I/O's
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IEEE 1149.1 JTAG boundary scan
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32-bit
MIPS IV instruction set
point multiply-add instruction increases
performance in signal processing and graphics
applications
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Conditional moves to reduce branch frequency
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Index address modes (register + register)
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Floating
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Embedded application enhancements
DSP integer Multiply-Accumulate instruction
and 3 operand multiply instruction
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I and D cache locking by set
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Optional dedicated exception vector for interrupts
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Specialized
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Integrated on-chip caches
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16KB
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16KB
instruction - 2 way set associative
data - 2 way set associative
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Virtually indexed, physically tagged
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Write-back and write-through on per page basis
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Early restart on data cache misses
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Fully static CMOS design with power down logic
Standby reduced power mode with WAIT instruction
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2.5 Watts typical with less than 70 mA standby current
128-pin Power Quad-4 package (F22),
Consult Factory for
package configuration
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Integrated memory management unit
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Fully
associative joint TLB (shared by I and D translations)
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48 dual entries map 96 pages
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Variable page size (4KB to 16MB in 4x increments)
Block Diagram
Data Set A
Store Buffer
Phase Lock Loop
Instruction Set A
Data Tag A
DTLB Physical
Data Tag B
Instruction Select
Sys AD
Integer Instruction Register
Write Buffer
Read Buffer
Data Set B
Instruction Tag B
DBus
FPIBus
Control
Tag
Floating-point
Register File
Floating point Control
Unpacker/Packer
Aux Tag
Load Aligner
Joint TLB
Integer Register File
Integer/Address Adder
Integer Control
Coprocessor 0
DVA
System/Memory
Control
IVA
Data TLB Virtual
IntIBus
Address Buffer
Instruction Tag A
ITLB Physical
Instruction Set B
FP Instruction Register
Floating-point
MAdd, Add, Sub,Cvt
Div, SqRt
Shifter/Store Aligner
Logic Unit
ABus
PC Incrementer
Branch Adder
Instruction TLB Virtual
Integer Multiply, Divide
Program Counter
Preliminary
eroflex Circuit Technology – RISC TurboEngines For The Future © SCD5230 REV 1 12/22/98
DESCRIPTION
The ACT5230 is a highly integrated superscalar
microprocessor that implements a superset of the
MIPS IV Instruction Set Architecture(ISA). It has a
high performance 64-bit integer unit, a high
throughput, fully pipelined 64-bit floating point unit,
an operating system friendly memory management
unit with a 48-entry fully associative TLB, a 16 KByte
2-way set associative instruction cache, a 16 KByte
2-way set associative data cache, and a
high-performance 32-bit system interface. The
ACT5230 can issue both an integer and a floating
point instruction in the same cycle.
The ACT5230 is ideally suited for high-end
embedded
control
applications
such
as
internetworking,
high
performance
image
manipulation, high speed printing, and 3-D
visualization.
therefore fully upward compatible with applications
that run on processors implementing the earlier
generation MIPS I-III instruction sets. Additionally,
the ACT5230 includes two implementation specific
instructions not found in the baseline MIPS IV ISA
but that are useful in the embedded market place.
Described in detail in the QED RM5230 datasheet,,
these instructions are integer multiply-accumulate
and 3-operand integer multiply.
The ACT5230 integer unit includes thirty-two
general purpose 64-bit registers, a load/store
architecture with single cycle ALU operations (add,
sub, logical, shift) and an autonomous multiply/divide
unit. Additional register resources include: the HI/LO
result registers for the two-operand integer multiply/
divide operations, and the program counter(PC).
Register File
The ACT5230 has thirty-two general purpose
registers with register location 0 hard wired to zero.
These registers are used for scalar integer
operations and address calculation. The register file
has two read ports and one write port and is fully
bypassed to minimize operation latency in the
pipeline.
HARDWARE OVERVIEW
The ACT5230 offers a high-level of integration
targeted
at
high-performance
embedded
applications. Some of the key elements of the
ACT5230 are briefly described below.
Superscalar Dispatch
The ACT5230 has an efficient asymmetric
superscalar dispatch unit which allows it to issue an
integer instruction and a floating-point computation
instruction simultaneously. With respect to
superscalar issue, 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,
converts, etc. In combination with its high throughput
fully pipelined floating-point execution unit, the
superscalar capability of the ACT5230 provides
unparalleled price/performance in computationally
intensive embedded applications.
ALU
The ACT5230 ALU consists of the integer adder/
subtractor, the logic unit, and the shifter. The adder
performs address calculations in addition to
arithmetic operations, the logic unit performs all
logical and zero shift data moves, and the shifter
performs shifts and store alignment operations. Each
of these units is optimized to perform all operations in
a single processor cycle
CPU Registers
Like all MIPS ISA processors, the ACT5230 CPU
has a simple, clean user visible state consisting of 32
general purpose registers, two special purpose
registers for integer multiplication and division, a
program counter, and no condition code bits.
For Detail Information regarding the operation of
the Quantum Effect Design (QED) RISCMark™
RM5230™, 32-Bit Superscalar Microprocessor see
the QED datasheet (Revision 1.2 July 1998).
Pipeline
For integer operations, loads, stores, and other
non-floating-point operations, the ACT5230 uses the
simple 5-stage pipeline also found in the QED
circuits R4600, R4700, and R5000. In addition to this
standard pipeline, the ACT5230 uses an extended
seven stage pipeline for floating-point operations.
Like the QED R5000, the ACT5230 does virtual to
physical translation in parallel with cache access.
Integer Unit
Like the QED R5000, the ACT5230 implements
the MIPS IV Instruction Set Architecture, and is
Aeroflex Circuit Technology
2
SCD5230 REV 1 12/22/98 Plainview NY (516) 694-6700
Embedded System
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