87 lines
2.3 KiB
C
87 lines
2.3 KiB
C
|
/* $Id: duff.c,v 1.2 2005/04/04 11:34:58 csg Exp $ */
|
||
|
|
|
||
|
|
/*----------------------------------------------------------------------
|
||
|
|
* WCET Benchmark created by Jakob Engblom, Uppsala university,
|
||
|
|
* February 2000.
|
||
|
|
*
|
||
|
|
* The purpose of this benchmark is to force the compiler to emit an
|
||
|
|
* unstructured loop, which is usually problematic for WCET tools to
|
||
|
|
* handle.
|
||
|
|
*
|
||
|
|
* The execution time should be constant.
|
||
|
|
*
|
||
|
|
* The original code is "Duff's Device", see the Jargon File, e.g. at
|
||
|
|
* http://www.tf.hut.fi/cgi-bin/jargon. Created in the early 1980s
|
||
|
|
* as a way to express loop unrolling in C.
|
||
|
|
*
|
||
|
|
*----------------------------------------------------------------------*/
|
||
|
|
|
||
|
|
#define ARRAYSIZE 100
|
||
|
|
#define INVOCATION_COUNT 43 /* exec time depends on this one! */
|
||
|
|
|
||
|
|
|
||
|
|
void duffcopy( char *to, char *from, int count)
|
||
|
|
{
|
||
|
|
int n=(count+7)/8;
|
||
|
|
switch(count%8){
|
||
|
|
case 0: do{ *to++ = *from++;
|
||
|
|
case 7: *to++ = *from++;
|
||
|
|
case 6: *to++ = *from++;
|
||
|
|
case 5: *to++ = *from++;
|
||
|
|
case 4: *to++ = *from++;
|
||
|
|
case 3: *to++ = *from++;
|
||
|
|
case 2: *to++ = *from++;
|
||
|
|
case 1: *to++ = *from++;
|
||
|
|
} while(--n>0);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void initialize( char *arr, int length)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
for(i=0;i<length;i++)
|
||
|
|
{
|
||
|
|
arr[i] = length-i;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
char source[ARRAYSIZE];
|
||
|
|
char target[ARRAYSIZE];
|
||
|
|
|
||
|
|
void main(void)
|
||
|
|
{
|
||
|
|
initialize( source, ARRAYSIZE );
|
||
|
|
duffcopy( source, target, INVOCATION_COUNT );
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/*------------------------------------------------------------
|
||
|
|
* $Id: duff.c,v 1.2 2005/04/04 11:34:58 csg Exp $
|
||
|
|
*------------------------------------------------------------
|
||
|
|
* $Log: duff.c,v $
|
||
|
|
* Revision 1.2 2005/04/04 11:34:58 csg
|
||
|
|
* again
|
||
|
|
*
|
||
|
|
* Revision 1.1 2005/03/29 09:34:13 jgn
|
||
|
|
* New file.
|
||
|
|
*
|
||
|
|
* Revision 1.8 2000/10/16 07:48:15 jakob
|
||
|
|
* *** empty log message ***
|
||
|
|
*
|
||
|
|
* Revision 1.7 2000/05/22 11:02:18 jakob
|
||
|
|
* Fixed minor errors.
|
||
|
|
*
|
||
|
|
* Revision 1.6 2000/02/27 16:56:52 jakob
|
||
|
|
* *** empty log message ***
|
||
|
|
*
|
||
|
|
* Revision 1.5 2000/02/15 14:09:24 jakob
|
||
|
|
* no message
|
||
|
|
*
|
||
|
|
* Revision 1.2 2000/02/15 13:32:16 jakob
|
||
|
|
* Added duff's device to benchmark suite for LCTES 00 paper.
|
||
|
|
*
|
||
|
|
*
|
||
|
|
*------------------------------------------------------------*/
|