Freescale Semiconductor
Technical Data
This document is primarily concerned with the MPC7448, which is targeted at networking and computing systems applications. This document describes pertinent electrical and physical characteristics of the MPC7448. For information regarding specific MPC7448 part numbers covered by this document and part numbers covered by other documents, refer to Section11, “Part Numbering and Marking.” For functional characteristics of the processor, refer to the MPC7450 RISC Microprocessor Family Reference Manual.
To locate any published updates for this document, refer to the website listed on the back cover of this document.
1Overview
The MPC7448 is the sixth implementation of fourth-generation(G4) microprocessors from Freescale. The
MPC7448, built on Power Architecture™ technology, implements the PowerPC™ instruction t archite
cture version 1.0 and is targeted at networking and computing systems applications. The MPC7448 consists of a processor core and a 1-Mbyte L2.
Figure1 shows a block diagram of the MPC7448. The core is a high-performance superscalar design supporting a
伦敦标志性建筑double-precision floating-point unit and a SIMD multimedia unit. The memory storage subsystem supports the MPX bus protocol and a subt of the 60x bus protocol to main memory and other system resources.贫困生申请书
Document Number:MPC7448EC
Rev. 4, 3/2007
Contents
1.Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.Comparison with the MPC7447A, MPC7447,
MPC7445, and MPC7441 . . . . . . . . . . . . . . . . . . . . . . 7
4.General Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.Electrical and Thermal Characteristics . . . . . . . . . . . . 9
6.Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.Pinout Listings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8.Package Description . . . . . . . . . . . . . . . . . . . . . . . . . 29
9.System Design Information . . . . . . . . . . . . . . . . . . . 35
10.Document Revision History . . . . . . . . . . . . . . . . . . . 55
表白的句子
11.Part Numbering and Marking . . . . . . . . . . . . . . . . . . 57
MPC7448
RISC Microprocessor Hardware Specifications
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Overview
Figure1. MPC7448 Block Diagram
Features
2Features
This ction summarizes features of the MPC7448 implementation.
Major features of the MPC7448 are as follows:
•High-performance, superscalar microprocessor
—Up to four instructions can be fetched from the instruction cache at a time.
—Up to three instructions plus a branch instruction can be dispatched to the issue queues at a time.
—Up to 12 instructions can be in the instruction queue (IQ).
—Up to 16 instructions can be at some stage of execution simultaneously.
—Single-cycle execution for most instructions
—
gatingOne instruction per clock cycle throughput for most instructions
—Seven-stage pipeline control
•Eleven independent execution units and three register files
—Branch processing unit (BPU) features static and dynamic branch prediction
–128-entry (32-t, four-way t-associative) branch target instruction cache (BTIC), a cache of branch instructions that have been encountered in branch/loop code quences. If a target
instruction is in the BTIC, it is fetched into the instruction queue a cycle sooner than it can
be made available from the instruction cache. Typically, a fetch that hits the BTIC provides
the first four instructions in the target stream.
–2048-entry branch history table (BHT) with 2 bits per entry for four levels of
prediction—not taken, strongly not taken, taken, and strongly taken
–Up to three outstanding speculative branches
–Branch instructions that do not update the count register (CTR) or link register (LR) are often removed from the instruction stream.
–Eight-entry link register stack to predict the target address of Branch Conditional to Link Register (bclr) instructions
—Four integer units (IUs) that share 32 GPRs for integer operands
–Three identical IUs (IU1a, IU1b, and IU1c) can execute all integer instructions except multiply, divide, and move to/from special-purpo register instructions.中国人民武装警察部队学院
–IU2 executes miscellaneous instructions, including the CR logical operations, integer multiplication and division instructions, and move to/from special-purpo register
instructions.
—Five-stage FPU and 32-entry FPR file
–Fully IEEE Std. 754™-1985–compliant FPU for both single- and double-precision operations
–Supports non-IEEE mode for time-critical operations
–Hardware support for denormalized numbers
–Thirty-two 64-bit FPRs for single- or double-precision operands
Features
—Four vector units and 32-entry vector register file (VRs)
–V ector permute unit (VPU)
–V ector integer unit 1 (VIU1) handles short-latency AltiV ec™ integer instructions, such as vector add instructions (for example, vaddsbs, vaddshs, and vaddsws).
–V ector integer unit 2 (VIU2) handles longer-latency AltiVec integer instructions, such as vector multiply add instructions (for example, vmhaddshs, vmhraddshs,and
vmladduhm).
–V ector floating-point unit (VFPU)
—Three-stage load/store unit (LSU)
–Supports integer, floating-point, and vector instruction load/store traffic
–Four-entry vector touch queue (VTQ) supports all four architected AltiV ec data stream operations
–Three-cycle GPR and AltiVec load latency (byte, half word, word, vector) with one-cycle throughput
–Four-cycle FPR load latency (single, double) with one-cycle throughput
–No additional delay for misaligned access within double-word boundary
– A dedicated adder calculates effective address (EAs).
–Supports store gathering
–Performs alignment, normalization, and precision conversion for floating-point data
–Executes cache control and TLB instructions
–Performs alignment, zero padding, and sign extension for integer data
–Supports hits under miss (multiple outstanding miss)
–Supports both big- and little-endian modes, including misaligned little-endian access •Three issue queues, FIQ, VIQ, and GIQ, can accept as many as one, two, and three instructions, respectively, in a cycle. Instruction dispatch requires the following:
—Instructions can only be dispatched from the three lowest IQ entries—IQ0, IQ1, and IQ2.
—A maximum of three instructions can be dispatched to the issue queues per clock cycle.
—Space must be available in the CQ for an instruction to dispatch (this includes instructions that are assigned a space in the CQ but not in an issue queue).
•Rename buffers
—16 GPR rename buffers
—16 FPR rename buffers
—16 VR rename buffers
•Dispatch unit
—
Decode/dispatch stage fully decodes each instruction
•Completion unit
—Retires an instruction from the 16-entry completion queue (CQ) when all instructions ahead of it have been completed, the instruction has finished executing, and no exceptions are pending —Guarantees quential programming model (preci exception model)
Features
—Monitors all dispatched instructions and retires them in order
—Tracks unresolved branches and flushes instructions after a mispredicted branch
—Retires as many as three instructions per clock cycle
•Separate on-chip L1 instruction and data caches (Harvard architecture)
—32-Kbyte, eight-way t-associative instruction and data caches
形容美味—Pudo least-recently-ud (PLRU) replacement algorithm
—32-byte (eight-word) L1 cache block
—Physically indexed/physical tags
—Cache write-back or write-through operation programmable on a per-page or per-block basis —Instruction cache can provide four instructions per clock cycle; data cache can provide four words per clock cycle
—Caches can be disabled in software.
—Caches can be locked in software.
—MESI data cache coherency maintained in hardware
—Separate copy of data cache tags for efficient snooping
—Parity support on cache
—No snooping of instruction cache except for icbi instruction
—Data cache supports AltiVec LRU and transient instructions
—Critical double- and/or quad-word forwarding is performed as needed. Critical quad-word forwarding is ud for AltiV ec loads and instruction fetches. Other access u critical
double-word forwarding.
•Level 2 (L2) cache interface
—On-chip, 1-Mbyte, eight-way t-associative unified instruction and data cache
—Cache write-back or write-through operation programmable on a per-page or per-block basis —Parity support on cache tags
—ECC or parity support on data
—Error injection allows testing of error recovery software
•Separate memory management units (MMUs) for instructions and data
—52-bit virtual address, 32- or 36-bit physical address
—Address translation for 4-Kbyte pages, variable-sized blocks, and 256-Mbyte gments
—Memory programmable as write-back/write-through, caching-inhibited/caching-allowed, and memory coherency enforced/memory coherency not enforced on a page or block basis —Separate IBATs and DBA Ts (eight each) also defined as SPRs
—Separate instruction and data translation lookaside buffers (TLBs)
–Both TLBs are 128-entry, two-way t-associative and u an LRU replacement algorithm.
名宦–TLBs are hardware- or software-reloadable (that is, a page table arch is performed in hardware or by system software on a TLB miss).
