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NIHCL-3.0
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STACKPRO.C
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1990-05-20
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/* StackProc.c -- Implementation of Process with stack shared with main() process
THIS SOFTWARE FITS THE DESCRIPTION IN THE U.S. COPYRIGHT ACT OF A
"UNITED STATES GOVERNMENT WORK". IT WAS WRITTEN AS A PART OF THE
AUTHOR'S OFFICIAL DUTIES AS A GOVERNMENT EMPLOYEE. THIS MEANS IT
CANNOT BE COPYRIGHTED. THIS SOFTWARE IS FREELY AVAILABLE TO THE
PUBLIC FOR USE WITHOUT A COPYRIGHT NOTICE, AND THERE ARE NO
RESTRICTIONS ON ITS USE, NOW OR SUBSEQUENTLY.
Author:
K. E. Gorlen
Bg. 12A, Rm. 2033
Computer Systems Laboratory
Division of Computer Research and Technology
National Institutes of Health
Bethesda, Maryland 20892
Phone: (301) 496-1111
uucp: uunet!nih-csl!kgorlen
Internet: kgorlen@alw.nih.gov
January, 1988
Function:
Modification History:
$Log: StackProc.c,v $
* Revision 3.0 90/05/20 00:21:30 kgorlen
* Release for 1st edition.
*
*/
#include "StackProc.h"
#include "Scheduler.h"
#include "nihclIO.h"
#define THIS StackProc
#define BASE Process
#define BASE_CLASSES BASE::desc()
#define MEMBER_CLASSES
#define VIRTUAL_BASE_CLASSES
DEFINE_ABSTRACT_CLASS(StackProc,1,"$Header: /afs/alw.nih.gov/unix/sun4_40c/usr/local/src/nihcl-3.0/share/lib/RCS/StackProc.c,v 3.0 90/05/20 00:21:30 kgorlen Rel $",NULL,NULL);
StackProc::StackProc(const char* name, stackTy* bottom, int priority, unsigned long size)
: BASE(name, bottom, priority)
{
stack_top = topOfStack();
stack_save_size = size;
if (size != 0) stack_save = new stackTy[size];
else stack_save = 0;
saveStack();
}
StackProc::StackProc(stackTy* bottom, int priority)
: BASE(bottom, priority)
// contructor for MAIN process
{
stack_top = bottom;
stack_save = 0;
stack_save_size = 0;
Scheduler::main_stack_process = this;
add(); // add MAIN process to Scheduler runlist
}
StackProc::StackProc(OIOifd& fd) : BASE(fd) {}
StackProc::StackProc(OIOin& strm) : BASE(strm) {}
StackProc::~StackProc()
{
delete stack_save;
}
void StackProc::saveStack()
// save the stack for this Process
{
#if STACK_GROWS_DOWN
unsigned long size = stack_bottom - stack_top;
#else
unsigned long size = stack_top - stack_bottom;
#endif
if (stack_save_size < size) {
if (stack_save_size != 0) delete stack_save;
stack_save = new stackTy[size];
stack_save_size = size;
}
#ifdef sparc
asm("t 0x03"); // ST_FLUSH_WINDOWS
#endif
#if STACK_GROWS_DOWN
copyStack(stack_top+1, stack_save, size);
#else
copyStack(stack_bottom, stack_save, size);
#endif
}
void StackProc::restoreStack(const stackTy* palloc)
{
Scheduler::main_stack_process = (StackProc*)Scheduler::active_process;
#if STACK_GROWS_DOWN
if (palloc != stack_top+1) {
cerr << "StackProc::restoreStack() assertion failed\n";
abort();
}
copyStack(stack_save, stack_top+1, stack_bottom-stack_top);
#else
if (palloc != Scheduler::main_stack_bottom) {
cerr << "StackProc::restoreStack() assertion failed\n";
abort();
}
copyStack(stack_save, stack_bottom, stack_top-stack_bottom);
#endif
LONGJMP(((StackProc*)Scheduler::active_process)->env, Scheduler::resume_new_process);
}
unsigned StackProc::size() const
{
#if STACK_GROWS_DOWN
return stack_bottom - stack_top;
#else
return stack_top - stack_bottom;
#endif
}
void StackProc::switchContext(Process* new_process)
{
stack_top = topOfStack();
save();
new_process->switchFrom(this);
}
void StackProc::switchFrom(HeapProc*)
// switch from active HeapProc to next StackProc
{
if (Scheduler::main_stack_process == this)
LONGJMP(env, Scheduler::resume_new_process);
Scheduler::main_stack_process->saveStack();
_LONGJMP(Scheduler::switcher, 1);
}
void StackProc::switchFrom(StackProc* active)
// switch from active StackProc to next StackProc
{
active->saveStack();
_LONGJMP(Scheduler::switcher, 1);
}