From 8d7393ad5f760a5dbaa5767a9ce586bbe18fce8e Mon Sep 17 00:00:00 2001 From: Joel Sherrill Date: Tue, 30 Jul 2002 21:43:53 +0000 Subject: 2002-07-30 Joel Sherrill * BSP_TIMES, ChangeLog, Makefile.am, arm.texi, bsp.t, callconv.t, cpumodel.t, cputable.t, fatalerr.t, intr_NOTIMES.t, memmodel.t, preface.texi, stamp-vti, timeBSP.t, timing.texi, version.texi, wksheets.texi: New files as ARM supplement initial version added. --- doc/supplements/arm/memmodel.t | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 doc/supplements/arm/memmodel.t (limited to 'doc/supplements/arm/memmodel.t') diff --git a/doc/supplements/arm/memmodel.t b/doc/supplements/arm/memmodel.t new file mode 100644 index 0000000000..bf543364c7 --- /dev/null +++ b/doc/supplements/arm/memmodel.t @@ -0,0 +1,38 @@ +@c +@c COPYRIGHT (c) 1988-2002. +@c On-Line Applications Research Corporation (OAR). +@c All rights reserved. +@c +@c $Id$ +@c + +@chapter Memory Model + +@section Introduction + +A processor may support any combination of memory +models ranging from pure physical addressing to complex demand +paged virtual memory systems. RTEMS supports a flat memory +model which ranges contiguously over the processor's allowable +address space. RTEMS does not support segmentation or virtual +memory of any kind. The appropriate memory model for RTEMS +provided by the targeted processor and related characteristics +of that model are described in this chapter. + +@section Flat Memory Model + +Members of the ARM family newer than Version 3 support a flat +32-bit address space with addresses ranging from 0x00000000 to +0xFFFFFFFF (4 gigabytes). Each address is represented by a +32-bit value and is byte addressable. +The address may be used to reference a +single byte, word (2-bytes), or long word (4 bytes). Memory +accesses within this address space are performed in the endian +mode that the processor is configured for. In general, ARM +processors are used in little endian mode. + +Some of the ARM family members such as the +920 and 720 include an MMU and thus support virtual memory and +segmentation. RTEMS does not support virtual memory or +segmentation on any of the ARM family members. + -- cgit v1.2.3