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diff --git a/doc/supplements/i386/memmodel.texi b/doc/supplements/i386/memmodel.texi deleted file mode 100644 index 6a16cbb35f..0000000000 --- a/doc/supplements/i386/memmodel.texi +++ /dev/null @@ -1,87 +0,0 @@ -@c -@c COPYRIGHT (c) 1988-1998. -@c On-Line Applications Research Corporation (OAR). -@c All rights reserved. -@c -@c $Id$ -@c - -@ifinfo -@node Memory Model, Memory Model Introduction, Calling Conventions User-Provided Routines, Top -@end ifinfo -@chapter Memory Model -@ifinfo -@menu -* Memory Model Introduction:: -* Memory Model Flat Memory Model:: -@end menu -@end ifinfo - -@ifinfo -@node Memory Model Introduction, Memory Model Flat Memory Model, Memory Model, Memory Model -@end ifinfo -@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. - -@ifinfo -@node Memory Model Flat Memory Model, Interrupt Processing, Memory Model Introduction, Memory Model -@end ifinfo -@section Flat Memory Model - -RTEMS supports the i386 protected mode, flat memory -model with paging disabled. In this mode, the i386 -automatically converts every address from a logical to a -physical address each time it is used. The i386 uses -information provided in the segment registers and the Global -Descriptor Table to convert these addresses. RTEMS assumes the -existence of the following segments: - -@itemize @bullet -@item a single code segment at protection level (0) which -contains all application and executive code. - -@item a single data segment at protection level zero (0) which -contains all application and executive data. -@end itemize - -The i386 segment registers and associated selectors -must be initialized when the initialize_executive directive is -invoked. RTEMS treats the segment registers as system registers -and does not modify or context switch them. - -This i386 memory model supports 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, half-word (2-bytes), or word (4 bytes). - -RTEMS does not require that logical addresses map -directly to physical addresses, although it is desirable in many -applications to do so. If logical and physical addresses are -not the same, then an additional selector will be required so -RTEMS can access the Interrupt Descriptor Table to install -interrupt service routines. The selector number of this segment -is provided to RTEMS in the CPU Dependent Information Table. - -By not requiring that logical addresses map directly -to physical addresses, the memory space of an RTEMS application -can be separated from that of a ROM monitor. For example, on -the Force Computers CPU386, the ROM monitor loads application -programs into a logical address space where logical address -0x00000000 corresponds to physical address 0x0002000. On this -board, RTEMS and the application use virtual addresses which do -not map to physical addresses. - -RTEMS assumes that the DS and ES registers contain -the selector for the single data segment when a directive is -invoked. This assumption is especially important when -developing interrupt service routines. - |