forked from Imagelibrary/rtems
42cf7c7c41
* cpu_supplement/.cvsignore, cpu_supplement/Makefile.am, cpu_supplement/arm.t, cpu_supplement/bfin.t, cpu_supplement/cpu_supplement.texi, cpu_supplement/i386.t, cpu_supplement/m68k.t, cpu_supplement/mips.t, cpu_supplement/powerpc.t, cpu_supplement/preface.texi, cpu_supplement/sh.t: Remove duplicated text from each CPU specific chapter. This text was necessary when each CPU was a separate manual but now only needs to be one place and that is in an introductory chapter. * cpu_supplement/general.t: New file.
56 lines
2.3 KiB
Plaintext
56 lines
2.3 KiB
Plaintext
@c
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@c COPYRIGHT (c) 1988-2006.
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@c On-Line Applications Research Corporation (OAR).
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@c All rights reserved.
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@c
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@c $Id$
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@c
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@ifinfo
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@node Preface, Port Specific Information, Top, Top
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@end ifinfo
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@unnumbered Preface
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The Real Time Executive for Multiprocessor Systems
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(RTEMS) is designed to be portable across multiple processor
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architectures. However, the nature of real-time systems makes
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it essential that the application designer understand certain
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processor dependent implementation details. These processor
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dependencies include calling convention, board support package
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issues, interrupt processing, exact RTEMS memory requirements,
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performance data, header files, and the assembly language
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interface to the executive.
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Each architecture represents a CPU family and usually there are
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a wide variety of CPU models within it. These models share a
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common Instruction Set Architecture (ISA) which often varies
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based upon some well-defined rules. There are often
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multiple implementations of the ISA and these may be from
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one or multiple vendors.
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On top of variations in the ISA, there may also be variations
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which occur when a CPU core implementation is combined with
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a set of peripherals to form a system on chip. For example,
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there are many ARM CPU models from numerous semiconductor
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vendors and a wide variety of peripherals. But at the
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ISA level, they share a common compaability.
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RTEMS depends upon this core similarity across the CPU models
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and leverages that to minimize the source code that is specific
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to any particular CPU core implementation or CPU model.
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This manual is separate and distinct from the RTEMS Porting
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Guide. That manual is a guide on porting RTEMS to a new
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architecture. This manual is focused on the more mundane
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CPU architecture specific issues that may impact
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application development. For example, if you need to write
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a subroutine in assembly language, it is critical to understand
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the calling conventions for the target architecture.
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The first chapter in this manual describes these issues
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in general terms. In a sense, it is posing the questions
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one should be aware may need to be answered and understood
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when porting an RTEMS application to a new architecture.
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Each subsequent chapter gives the answers to those questions
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for a particular CPU architecture.
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