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Text File  |  1992-06-30  |  809b  |  76 lines
  1.  
  2. /*
  3.     Listing 4
  4. */
  5.  
  6. #include <stdio.h>
  7. #include "enet_cs.h"
  8.  
  9. int NODE1_num, NODE2_num;
  10.  
  11. extern int node;
  12.  
  13. extern FILE *fp;
  14.  
  15. int critical_section()
  16. {
  17.  
  18.     switch (node) {
  19.  
  20.         case NODE0:
  21.  
  22.             NODE1_num = cs_read (NODE1_LOC);
  23.             NODE2_num = cs_read (NODE2_LOC);
  24.  
  25.             if ( (NODE1_num == READY) && (NODE2_num == READY) ) {
  26.  
  27.                 NODE1_num = CLEAR;
  28.  
  29.                 cs_write ( NODE1_LOC, NODE1_num);            
  30.  
  31.                 NODE2_num = CLEAR;
  32.  
  33.                 cs_write ( NODE2_LOC, NODE2_num);
  34.  
  35.                 return(STOP);
  36.  
  37.             } else {
  38.  
  39.                 return(NORMAL);
  40.  
  41.             }
  42.  
  43.         break;
  44.  
  45.         case NODE1:
  46.  
  47.             NODE1_num = READY;
  48.  
  49.             cs_write ( NODE1_LOC, NODE1_num);            
  50.  
  51.             return(STOP);
  52.  
  53.         break;
  54.  
  55.         case NODE2:
  56.  
  57.             NODE2_num = READY;
  58.  
  59.             cs_write ( NODE2_LOC, NODE2_num);
  60.  
  61.             return(STOP);
  62.  
  63.         break;
  64.  
  65.         default:
  66.             printf ("Error: invalid processor\n");
  67.             exit(0);
  68.         break;
  69.             
  70.  
  71.     }
  72.  
  73.  
  74. }
  75.  
  76.