check1.h

操作系统SunOS 4.1.3版本的源码

/* @(#)check1.h 1.1 92/07/30 Copyr 1987 Sun Micro */
/* Copyright (C) 1987. Sun Microsystems, Inc. */
/*
 * This source code is a product of Sun Microsystems, Inc. and is provided
 * for unrestricted use provided that this legend is included on all tape
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 * program developed by the user.
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 * THIS PROGRAM CONTAINS SOURCE CODE COPYRIGHTED BY SUN MICROSYSTEMS, INC.
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 * SUN MICROSYSTEMS, INC., MAKES NO REPRESENTATIONS ABOUT THE SUITABLITY
 * OF SUCH SOURCE CODE FOR ANY PURPOSE.  IT IS PROVIDED "AS IS" WITHOUT
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#ifndef _lwp_m68k_chk_h
#define _lwp_m68k_chk_h

#endif /*!_lwp_m68k_chk_h*/

/*
 * Compare sp to its lowest legal point.
 * If the stack exceeds its bounds, set a value and return.
 * This macro can be used in procedures used by a lwp to check the
 * integrity of the stack (protect against bumping into another lwp's stack).
 * The overhead (STKOVERHEAD) is silently allocated IN ADDITION TO
 * the amount specfied in lwp_create.
 * This ensures that even if CHECK just barely
 * succeeds, there is room to call the next procedure in most cases
 * without trashing anyone else's stack.
 * This only fails when you're up against the limit and
 * the next procedure has lots of arguments.
 * If you never call a procedure with more than 100 bytes of arguments or so,
 * there should be no problem.
 * Roughly, what we have here:
 *	register unsigned sp;
 *	if (sp <= (unsigned)((int)__CurStack + STKOVERHEAD)) {
 *		location = result;
 *		return;
 *	}
 * Note that this macro depends upon the definitions in machdep.h.
 * This macro is only useful when no mmgt-assisted red-zones are available.
 *
 * The program checkassym.c generates the macro.
 */