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MPC8240 Integrated Processor User’s Manual
Cache Implementation
separate instructions. Decoupling computational instructions from memory accesses
increases throughput by facilitating pipelining.
PowerPC processors follow the program flow when they are in the normal execution state.
However, the flow of instructions can be interrupted directly by the execution of an
instruction or by an asynchronous event. Either kind of exception may cause one of several
components of the system software to be invoked.
5.3.2.3 MPC8240 Implementation-Specific Instruction Set
The MPC8240 processor core instruction set is defined as follows:
•
The processor core provides hardware support for all 32-bit PowerPC instructions.
•
The processor core provides two implementation-specific instructions used for
software table search operations following TLB misses:
— Load Data TLB Entry (tlbld)
— Load Instruction TLB Entry (tlbli)
•
The processor core implements the following instructions defined as optional by the
PowerPC architecture:
— Floating Select (fsel)
— Floating Reciprocal Estimate Single-Precision (fres)
— Floating Reciprocal Square Root Estimate (frsqrte)
— Store Floating-Point as Integer Word Indexed (stfiwx)
— External Control In Word Indexed (eciwx)
— External Control Out Word Indexed (ecowx)
The MPC8240 does not provide the hardware support for misaligned eciwx and ecowx
instructions provided by the MPC603e processor. An alignment exception is taken if these
instructions are not word-aligned.
5.4 Cache Implementation
The MPC8240 processor core has separate data and instruction caches. The cache
implementation is described in the following sections.
5.4.1 PowerPC Cache Model
The PowerPC architecture does not define hardware aspects of cache implementations. For
example, some PowerPC processors, including the MPC8240’s processor core, have
separate instruction and data caches (Harvard architecture); others, such as the PowerPC
601® microprocessor implement a unified cache.
Summary of Contents for MPC8240
Page 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Page 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Page 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Page 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Page 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Page 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Page 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Page 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Page 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Page 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Page 516: ...16 14 Watchpoint Trigger Applications ...
Page 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Page 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Page 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...