81 lines
2.9 KiB
C
81 lines
2.9 KiB
C
|
/* This example accompanies the book
|
||
|
|
Embedded Systems: Real-Time Operating Systems for the Arm Cortex, Volume 3,
|
||
|
|
ISBN: 978-1466468863, Jonathan Valvano, copyright (c) 2026
|
||
|
|
|
||
|
|
Copyright 2026 by Jonathan W. Valvano, valvano@mail.utexas.edu
|
||
|
|
You may use, edit, run or distribute this file
|
||
|
|
as long as the above copyright notice remains
|
||
|
|
|
||
|
|
THIS SOFTWARE IS PROVIDED "AS IS". NO WARRANTIES, WHETHER EXPRESS, IMPLIED
|
||
|
|
OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
|
||
|
|
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
|
||
|
|
VALVANO SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL,
|
||
|
|
OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
|
||
|
|
For more information about my classes, my research, and my books, see
|
||
|
|
http://users.ece.utexas.edu/~valvano/
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define MAX 15000/100
|
||
|
|
char Times[MAX]; // filled with spaces
|
||
|
|
char bestTimes[MAX];
|
||
|
|
int bestj,bestk,bestl;
|
||
|
|
int ScheduleFinder(int ta, int tb, int tc, int td){
|
||
|
|
int i,j,k,l; int jitter=0;
|
||
|
|
int thei,thejitter;
|
||
|
|
// find schedule for task b with min jitter
|
||
|
|
jitter = 100000;
|
||
|
|
for(j=0; j<tb; j++){ // slide factor task B
|
||
|
|
for(k=0; k<tc; k++){ // slide factor task C
|
||
|
|
for(l=0; l<td; l++){ // slide factor task D
|
||
|
|
for(i=0; i<MAX; i++) Times[i] = ' '; // space means time not used
|
||
|
|
for(i=0; i<MAX; i=i+ta) Times[i] = 'a'; // schedule task a
|
||
|
|
thejitter = 0;
|
||
|
|
for(i=j; i<MAX; i=i+tb){
|
||
|
|
if(Times[i]== ' '){
|
||
|
|
Times[i] = 'b'; // schedule B no jitter
|
||
|
|
} else{
|
||
|
|
thei = i; // search for place to schedule
|
||
|
|
do{
|
||
|
|
thei++;
|
||
|
|
thejitter++;
|
||
|
|
}
|
||
|
|
while((Times[thei]!= ' ')&&(thei<MAX));
|
||
|
|
if(thei<MAX) Times[thei] = 'B'; // schedule B with jitter
|
||
|
|
}
|
||
|
|
}
|
||
|
|
for(i=k; i<MAX; i=i+tc){
|
||
|
|
if(Times[i]== ' '){
|
||
|
|
Times[i] = 'c'; // schedule C no jitter
|
||
|
|
} else{
|
||
|
|
thei = i; // search for place to schedule
|
||
|
|
do{
|
||
|
|
thei++;
|
||
|
|
thejitter++;
|
||
|
|
}
|
||
|
|
while((Times[thei]!= ' ')&&(thei<MAX));
|
||
|
|
if(thei<MAX) Times[thei] = 'C'; // schedule C with jitter
|
||
|
|
}
|
||
|
|
}
|
||
|
|
for(i=l; i<MAX; i=i+td){
|
||
|
|
if(Times[i]== ' '){
|
||
|
|
Times[i] = 'd'; // schedule D no jitter
|
||
|
|
} else{
|
||
|
|
thei = i; // search for place to schedule
|
||
|
|
do{
|
||
|
|
thei++;
|
||
|
|
thejitter++;
|
||
|
|
}
|
||
|
|
while((Times[thei]!= ' ')&&(thei<MAX));
|
||
|
|
if(thei<MAX) Times[thei] = 'D'; // schedule D with jitter
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if(thejitter<jitter){
|
||
|
|
bestj = j; bestk = k; bestl = l;
|
||
|
|
jitter = thejitter;
|
||
|
|
for(i=0; i<MAX; i++) bestTimes[i] = Times[i]; // best schedule
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return jitter;
|
||
|
|
}
|