GME: sched.c Source File

00001 
00006 #include <malloc.h>
00007 
00008 #include "libmgk.h"
00009 #include "allocate.h"
00010 
00011 unsigned long __mgk_tick = 0L;
00012 static mgk_node *schedule = NULL;
00013 static int ready_qlen = 0;
00014 
00015 #define NODE_DYNPRI(n) (unsigned int)(  \
00016   (n)->priority +                       \
00017   __mgk_tick -                          \
00018   (n)->ready_time                       \
00019 )
00020 
00021 void
00022 __mgk_enqueue(mgk_node * node)
00023 {
00024   mgk_node **npp, *np;
00025   for (npp = &schedule; (np = *npp); npp = &np->next) {
00026     if (np == node) {
00027       return;
00028     }
00029     if (NODE_DYNPRI(np) < node->priority) {
00030       break;
00031     }
00032   }
00033   node->ready_time = __mgk_tick;
00034   node->next = np;
00035   *npp = node;
00036   ready_qlen++;
00037 }
00038 
00039 void
00040 __mgk_dequeue(mgk_node * node)
00041 {
00042   mgk_node **npp, *np;
00043   for (npp = &schedule; (np = *npp); npp = &np->next) {
00044     if (np == node) {
00045       *npp = np->next;
00046       ready_qlen--;
00047     }
00048   }
00049 }
00050 
00051 mgk_node *
00052 __mgk_next_node(void)
00053 {
00054   mgk_node *np = schedule;
00055   if (np) {
00056     schedule = np->next;
00057     __mgk_tick++;
00058     ready_qlen--;
00059   }
00060   return (np);
00061 }