RTSA-lab01-CacheAnalysis/test/src/duff.c

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2022-04-19 10:56:42 +02:00
/* $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.
*
*
*------------------------------------------------------------*/