www.pudn.com > vXworksBSPfors3c44b0.rar > dataSegPad.c

/* dataSegPad.c - padding for beginning of data segment */ 
 
/* Copyright 1984-1991 Wind River Systems, Inc. */ 
#include "copyright_wrs.h" 
 
/* 
modification history 
-------------------- 
01c,19oct92,jcf  change to include when INCLUDE_MMU_FULL defined. 
01b,28jul92,rdc  changed PAGE_SIZE to VM_PAGE_SIZE. 
01a,21jul92,rdc  written. 
*/ 
 
/* 
DESCRIPTION 
 
This module conditionally creates a data structure the size of one page; 
it is explicility listed as the first module on the load line when VxWorks 
is linked to insure that this data structure is the first item in the 
data segment.  This mechanism is needed to insure that the data segment 
does not overlap a page that is occupied by the text segment;  when text 
segment protection is turned on, all pages that contain text are write  
protected.  This insures that the data segment does not lie in a page that 
has been write protected.  If text segment protection has not been included, 
this module compiles into a null object module.  In an embedded system, this 
mechanism may not be needed if the loader explicitly places the data segment 
in a section of memory seperate from the text segment. 
 
*/ 
 
#include "vxWorks.h" 
#include "config.h" 
 
#ifdef	INCLUDE_MMU_FULL		/* bootroms will not ref dataSegPad.o */ 
 
char dataSegPad [VM_PAGE_SIZE] = {1}; 
 
#endif /* INCLUDE_MMU_FULL */