diff options
Diffstat (limited to 'i686/paging.h')
| -rw-r--r-- | i686/paging.h | 86 |
1 files changed, 43 insertions, 43 deletions
diff --git a/i686/paging.h b/i686/paging.h index f9c04a8..f5bfa78 100644 --- a/i686/paging.h +++ b/i686/paging.h @@ -1,59 +1,59 @@ #pragma once -// DirectoryEntry -// |31| | | | | | | | | | | | | | | | | | | |11| | 9| 8| 7| 6| 5| 4| 3| 2| 1| 0| -// | page table 4-kb aligned address | avail | G| S| | A| C| W| U| R| P| +/* DirectoryEntry + * |31| | | | | | | | | | | | | | | | | | | |11| | 9| 8| 7| 6| 5| 4| 3| 2| 1| 0| + * | page table 4-kb aligned address | avail | G| S| | A| C| W| U| R| P| */ struct __attribute__((packed)) DirectoryEntry { - unsigned present : 1; // 0: if set, the page is actually in physical memory - unsigned writeable : 1; // 1: if set, the page is read/write; otherwise the page is read-only - unsigned user : 1; // 2: if set, then page can be access by all; otherwise only the supervisor can access it - unsigned writethrough : 1; // 3: if set, write-through caching is enabled; otherwise write-back is enabled instead - unsigned cachedisable : 1; // 4: if set, the page will not be cached - unsigned accessed : 1; // 5: set by the CPU when the page is read from or written to - unsigned dirty : 1; // 6: used to determine whether a page has been written to - unsigned pagesize : 1; // 7: page size == 0 + unsigned present : 1; /* 0: if set, the page is actually in physical memory */ + unsigned writeable : 1; /* 1: if set, the page is read/write; otherwise the page is read-only */ + unsigned user : 1; /* 2: if set, then page can be access by all; otherwise only the supervisor can access it */ + unsigned writethrough : 1; /* 3: if set, write-through caching is enabled; otherwise write-back is enabled instead */ + unsigned cachedisable : 1; /* 4: if set, the page will not be cached */ + unsigned accessed : 1; /* 5: set by the CPU when the page is read from or written to */ + unsigned dirty : 1; /* 6: used to determine whether a page has been written to */ + unsigned pagesize : 1; /* 7: page size == 0 */ unsigned global : 1; - unsigned int __available__ : 3; // available to the OS + unsigned int __available__ : 3; /* available to the OS */ unsigned int address : 20; }; -_Static_assert(sizeof(struct DirectoryEntry) == 4, "DirectoryEntry size"); +/* TODO _Static_assert(sizeof(struct DirectoryEntry) == 4, "DirectoryEntry size"); */ -// DirectoryEntry4MB -// |31| | | | | | | | |22|21|20| | | | | | |13|12|11| | 9| 8| 7| 6| 5| 4| 3| 2| 1| 0| -// | bits 31-22 of address |RS| bits 39-22 of |AT| avail | G|PS| D| A|CD|WT|US|RW| P| -// | |VD| address +/* DirectoryEntry4MB + * |31| | | | | | | | |22|21|20| | | | | | |13|12|11| | 9| 8| 7| 6| 5| 4| 3| 2| 1| 0| + * | bits 31-22 of address |RS| bits 39-22 of |AT| avail | G|PS| D| A|CD|WT|US|RW| P| + * | |VD| address */ struct __attribute__((packed)) DirectoryEntry4MB { - unsigned present : 1; // 0: if set, the page is actually in physical memory - unsigned writeable : 1; // 1: if set, the page is read/write; otherwise the page is read-only - unsigned useraccess : 1; // 2: if set, then page can be access by all; otherwise only the supervisor can access it - unsigned writethrough : 1; // 3: if set, write-through caching is enabled; otherwise write-back is enabled instead - unsigned cachedisable : 1; // 4: if set, the page will not be cached - unsigned accessed : 1; // 5: set by the CPU when the page is read from or written to - unsigned dirty : 1; // 6: used to determine whether a page has been written to - unsigned pagesize : 1; // 7: page size == 1 - unsigned global : 1; // 8: - unsigned __available__ : 3; // 11..9 available to the OS - unsigned pat : 1; // 12: page attribute table + unsigned present : 1; /* 0: if set, the page is actually in physical memory */ + unsigned writeable : 1; /* 1: if set, the page is read/write; otherwise the page is read-only */ + unsigned useraccess : 1; /* 2: if set, then page can be access by all; otherwise only the supervisor can access it */ + unsigned writethrough : 1; /* 3: if set, write-through caching is enabled; otherwise write-back is enabled instead */ + unsigned cachedisable : 1; /* 4: if set, the page will not be cached */ + unsigned accessed : 1; /* 5: set by the CPU when the page is read from or written to */ + unsigned dirty : 1; /* 6: used to determine whether a page has been written to */ + unsigned pagesize : 1; /* 7: page size == 1 */ + unsigned global : 1; /* 8: */ + unsigned __available__ : 3; /* 11..9 available to the OS */ + unsigned pat : 1; /* 12: page attribute table */ unsigned int address_high : 8; - unsigned rsvd : 1; // 21 + unsigned rsvd : 1; /* 21 */ unsigned int address_low : 10; }; -_Static_assert(sizeof(struct DirectoryEntry4MB) == 4, "DirectoryEntry4M size"); +/* TODO _Static_assert(sizeof(struct DirectoryEntry4MB) == 4, "DirectoryEntry4M size"); */ -// TableEntry -// |31| | | | | | | | | | | | | | | | | | | |11| | 9| 8| 7| 6| 5| 4| 3| 2| 1| 0| -// | page table 4-kb aligned address | avail | G| | D| A| C| W|US|RW| P| +/* TableEntry + * |31| | | | | | | | | | | | | | | | | | | |11| | 9| 8| 7| 6| 5| 4| 3| 2| 1| 0| + * | page table 4-kb aligned address | avail | G| | D| A| C| W|US|RW| P| */ struct __attribute__((packed)) TableEntry { - unsigned present : 1; // if set, the page is actually in physical memory - unsigned writeable : 1; // if set, the page is read/write; otherwise the page is read-only - unsigned user : 1; // if set, then page can be access by all; otherwise only the supervisor can access it - unsigned writethrough : 1; // if set, write-through caching is enabled; otherwise write-back is enabled instead - unsigned cachedisable : 1; // if set, the page will not be cached - unsigned accessed : 1; // set by the CPU when the page is read from or written to - unsigned dirty : 1; // used to determine whether a page has been written to - unsigned pat : 1; // page attribute table? + unsigned present : 1; /* if set, the page is actually in physical memory */ + unsigned writeable : 1; /* if set, the page is read/write; otherwise the page is read-only */ + unsigned user : 1; /* if set, then page can be access by all; otherwise only the supervisor can access it */ + unsigned writethrough : 1; /* if set, write-through caching is enabled; otherwise write-back is enabled instead */ + unsigned cachedisable : 1; /* if set, the page will not be cached */ + unsigned accessed : 1; /* set by the CPU when the page is read from or written to */ + unsigned dirty : 1; /* used to determine whether a page has been written to */ + unsigned pat : 1; /* page attribute table? */ unsigned global : 1; - unsigned int __available__ : 3; // available to the OS + unsigned int __available__ : 3; /* available to the OS */ unsigned int address : 20; }; -_Static_assert(sizeof(struct TableEntry) == 4, "TableEntry size"); +/* TODO _Static_assert(sizeof(struct TableEntry) == 4, "TableEntry size"); */ |