pageframe.c

用于汇编领域的,运用于OS的MAIN函数.基于硬件基础的源代码

#include "mm.h"
struct page mem_map[MAXPGFRAME];
void init_mem_map(){
   int i;
   for(i=0;i<MAXPGFRAME;i++) mem_map[i].count=0; //free frame
}
unsigned long get_free_pgframe(){
// return the location of a free page grame
   int i;
   for(i=0;i<MAXPGFRAME;i++) 
      if (mem_map[i].count==0) {
	      mem_map[i].count=1;
		  printk("get free pgframe returning free frame at %x\n",i*PGSIZE);
		  return i*PGSIZE;
	  }
   panic("no free frame\n");
}
void  set_pgframe(unsigned long frame_loc){
   int n = frame_loc/PGSIZE;
   mem_map[n].count++;
}
void free_pgframe(unsigned long frame_loc){
   int n = frame_loc/PGSIZE;
   mem_map[n].count--;
}