/*--- tlb.h --- characteristic of the tlb ---*/
#include "mem.h"
#ifndef __TLB_H__
#define __TLB_H__

/*---- Stuff for grabbing pages and offsets off of addresses */
#define PHYS_MEM_SIZE (2*1024*1024)
#define PAGESIZE       4096
#define PAGEMASK       (~(PAGESIZE - 1))
#define PAGEOFFSETMASK (PAGESIZE-1)
#define PAGESHIFT      12

/* some utility routines */
#define GET_PAGE(addr)  (addr >> PAGESHIFT)
#define GET_OFFSET(addr) (addr & PAGEOFFSETMASK)



/*----  TLB routines and values */

/* invalid page */
#define INVALID       0xffffffff

/* tlb flags */
#define TLB_WRITE_PROTECT  1

/*
 *  Here's the format for the expected return value from a TLB fault 
 *     bits 0..19   - physical page #
 *     bits 20..31  - flags
 *
 *  We'll call this type a PTE (page table entry).  
 *     This is just an unsigned but it's
 *     easier to figure out what's going on this way
 */

typedef unsigned PTE;

#define TLB_PAGEMASK (0xfffff)
#define FLAGSHIFT 20

/* put together the flags and the page number to form a PTE */
#define TLB_MAKE_PTE(ppage,flags) ((flags << FLAGSHIFT) | ppage )

/* get the physical page number from the PTE */ 
#define TLB_GETPAGE(retval) ( retval & TLB_PAGEMASK )

/* get the flags out of the PTE */
#define TLB_GETFLAGS(retval) ( retval >> FLAGSHIFT)



void tlb_flush();  /* flush the tlb */
void tlb_invalidate(unsigned long vpage); /* invalidate all entries mapping this vpage */
mem_addr tlb_translate(unsigned long vaddr, c_rw rw);  /* translate vaddr to paddr */
void set_tlb_ppage(unsigned long vpage, PTE ptentry); 
void set_tlb_flags(unsigned long vpage, unsigned flags);



#endif __TLB_H__