From 72a62ad88f82fe1ffee50024db4dd0f3fa5806f7 Mon Sep 17 00:00:00 2001 From: Chris Johns Date: Thu, 3 Nov 2016 16:58:08 +1100 Subject: Rename all manuals with an _ to have a -. It helps released naming of files. --- cpu-supplement/preface.rst | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 cpu-supplement/preface.rst (limited to 'cpu-supplement/preface.rst') diff --git a/cpu-supplement/preface.rst b/cpu-supplement/preface.rst new file mode 100644 index 0000000..0fa6341 --- /dev/null +++ b/cpu-supplement/preface.rst @@ -0,0 +1,46 @@ +.. comment SPDX-License-Identifier: CC-BY-SA-4.0 + +.. COMMENT: COPYRIGHT (c) 1988-2002. +.. COMMENT: On-Line Applications Research Corporation (OAR). +.. COMMENT: All rights reserved. + +======= +Preface +======= + +The Real Time Executive for Multiprocessor Systems (RTEMS) is designed to be +portable across multiple processor architectures. However, the nature of +real-time systems makes it essential that the application designer understand +certain processor dependent implementation details. These processor +dependencies include calling convention, board support package issues, +interrupt processing, exact RTEMS memory requirements, performance data, header +files, and the assembly language interface to the executive. + +Each architecture represents a CPU family and usually there are a wide variety +of CPU models within it. These models share a common Instruction Set +Architecture (ISA) which often varies based upon some well-defined rules. +There are often multiple implementations of the ISA and these may be from one +or multiple vendors. + +On top of variations in the ISA, there may also be variations which occur when +a CPU core implementation is combined with a set of peripherals to form a +system on chip. For example, there are many ARM CPU models from numerous +semiconductor vendors and a wide variety of peripherals. But at the ISA level, +they share a common compatibility. + +RTEMS depends upon this core similarity across the CPU models and leverages +that to minimize the source code that is specific to any particular CPU core +implementation or CPU model. + +This manual is separate and distinct from the RTEMS Porting Guide. That manual +is a guide on porting RTEMS to a new architecture. This manual is focused on +the more mundane CPU architecture specific issues that may impact application +development. For example, if you need to write a subroutine in assembly +language, it is critical to understand the calling conventions for the target +architecture. + +The first chapter in this manual describes these issues in general terms. In a +sense, it is posing the questions one should be aware may need to be answered +and understood when porting an RTEMS application to a new architecture. Each +subsequent chapter gives the answers to those questions for a particular CPU +architecture. -- cgit v1.2.3