source: rtems/doc/supplements/i960/memmodel.t @ ae68ff0

4.104.114.84.95
Last change on this file since ae68ff0 was ae68ff0, checked in by Joel Sherrill <joel.sherrill@…>, on 05/27/97 at 12:40:11

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1@c
2@c  COPYRIGHT (c) 1988-1997.
3@c  On-Line Applications Research Corporation (OAR).
4@c  All rights reserved.
5@c
6
7@ifinfo
8@node Memory Model, Memory Model Introduction, Calling Conventions Leaf Procedures, Top
9@end ifinfo
10@chapter Memory Model
11@ifinfo
12@menu
13* Memory Model Introduction::
14* Memory Model Flat Memory Model::
15@end menu
16@end ifinfo
17
18@ifinfo
19@node Memory Model Introduction, Memory Model Flat Memory Model, Memory Model, Memory Model
20@end ifinfo
21@section Introduction
22
23A processor may support any combination of memory
24models ranging from pure physical addressing to complex demand
25paged virtual memory systems.  RTEMS supports a flat memory
26model which ranges contiguously over the processor's allowable
27address space.  RTEMS does not support segmentation or virtual
28memory of any kind.  The appropriate memory model for RTEMS
29provided by the targeted processor and related characteristics
30of that model are described in this chapter.
31
32@ifinfo
33@node Memory Model Flat Memory Model, Interrupt Processing, Memory Model Introduction, Memory Model
34@end ifinfo
35@section Flat Memory Model
36
37The i960CA supports a flat 32-bit address space with
38addresses ranging from 0x00000000 to 0xFFFFFFFF (4 gigabytes).
39Although the i960CA reserves portions of this address space,
40application code and data may be placed in any non-reserved
41areas.  Each address is represented by a 32-bit value and is
42byte addressable.  The address may be used to reference a single
43byte, half-word (2-bytes), word (4 bytes), double-word (8
44bytes), triple-word (12 bytes) or quad-word (16 bytes).  The
45i960CA does not support virtual memory or segmentation.
46
47The i960CA allows the memory space to be partitioned
48into sixteen regions which may be configured individually as big
49or little endian.  RTEMS assumes that the memory regions in
50which its code, data, and the RTEMS Workspace reside are
51configured as little endian.
52
53
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