From: Ben Pfaff Date: Mon, 27 Sep 2004 16:53:24 +0000 (+0000) Subject: Add PTSPAN. X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59bac3ac5e1f68e57fce97362cbce47559091dae;p=pintos-anon Add PTSPAN. Comments. --- diff --git a/src/threads/mmu.h b/src/threads/mmu.h index 4d4aa6a..64d82da 100644 --- a/src/threads/mmu.h +++ b/src/threads/mmu.h @@ -9,19 +9,19 @@ /* Virtual to physical translation works like this on an x86: - - The top 10 bits of the virtual address (bits 22:31) are used + - The top 10 bits of the virtual address (bits 22:32) are used to index into the page directory. If the PDE is marked "present," the physical address of a page table is read from the PDE thus obtained. If the PDE is marked "not present" then a page fault occurs. - - The next 10 bits of the virtual address (bits 12:21) are + - The next 10 bits of the virtual address (bits 12:22) are used to index into the page table. If the PTE is marked "present," the physical address of a data page is read from the PTE thus obtained. If the PTE is marked "not present" then a page fault occurs. - - The bottom 12 bits of the virtual address (bits 0:11) are + - The bottom 12 bits of the virtual address (bits 0:12) are added to the data page's physical base address, producing the final physical address. @@ -57,21 +57,22 @@ #define MASK(SHIFT, CNT) (((1ul << (CNT)) - 1) << (SHIFT)) -/* Page offset (bits 0:11). */ -#define PGSHIFT 0 /* First offset bit. */ -#define PGBITS 12 /* Number of offset bits. */ -#define PGMASK MASK(PGSHIFT, PGBITS) -#define PGSIZE (1 << PGBITS) - -/* Page table (bits 12:21). */ -#define PTSHIFT PGBITS /* First page table bit. */ -#define PTBITS 10 /* Number of page table bits. */ -#define PTMASK MASK(PTSHIFT, PTBITS) - -/* Page directory (bits 22:31). */ -#define PDSHIFT (PTSHIFT + PTBITS) /* First page dir bit. */ -#define PDBITS 10 /* Number of page dir bits. */ -#define PDMASK MASK(PDSHIFT, PDBITS) +/* Page offset (bits 0:12). */ +#define PGSHIFT 0 /* Index of first offset bit. */ +#define PGBITS 12 /* Number of offset bits. */ +#define PGMASK MASK(PGSHIFT, PGBITS) /* Page offset bits (0:12). */ +#define PGSIZE (1 << PGBITS) /* Bytes in a page. */ + +/* Page table (bits 12:22). */ +#define PTSHIFT PGBITS /* Index of first page table bit. */ +#define PTBITS 10 /* Number of page table bits. */ +#define PTMASK MASK(PTSHIFT, PTBITS) /* Page table bits (12:22). */ +#define PTSPAN (1 << PTBITS << PGBITS) /* Bytes covered by a page table. */ + +/* Page directory (bits 22:32). */ +#define PDSHIFT (PTSHIFT + PTBITS) /* First page dir bit. */ +#define PDBITS 10 /* Number of page dir bits. */ +#define PDMASK MASK(PDSHIFT, PDBITS) /* Page directory bits (22:32). */ /* Offset within a page. */ static inline unsigned pg_ofs (const void *va) {