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osMapTLB
Syntax
#include <ultra64.h>
void osMapTLB(s32 index, OSPageMask pm, void *vaddr, u32 evenpaddr,
u32 oddpaddr, s32 asid);
Explanation
The osMapTLB, osUnmapTLB, osUnmapTLBAll, and osSetTLBASID functions manage CPU virtual
address mapping. These calls provide low-level access to the CPU Translation Lookaside
Buffer (TLB). The remainder of the CPU virtual address space outside
of the direct mapped address spaces KSEG0 and KSEG1 are mapped address
spaces that use the TLB to specify the mapping to physical memory on a
per-page basis. The CPU TLB consists of 32 entries, which provide
mapping to 32 odd/even physical page pairs (64 total pages). Each TLB
entry is associated with a particular page size that varies from 4096
bytes to as much as 16 megabytes.
The osMapTLB function sets the TLB entry index, where index ranges from 0 to 31. The pm argument specifies the page size; it can be one of the following defined constants:
OS_PM_4K 4096 byte page size
OS_PM_16K 16384 byte page size
OS_PM_64K 65536 byte page size
OS_PM_256K 262144 byte page size
OS_PM_1M 1048576 byte page size
OS_PM_4M 4194304 byte page size
OS_PM_16M 16777216 byte page size
The vaddr argument specifies the beginning virtual address to map, and the evenpaddr and oddpaddr arguments specify the corresponding odd and even physical page addresses. A value of -1 for evenpaddr or oddpaddr
indicates that no mapping is to be made for the even or odd page,
respectively. The asid argument specifies an address space identifier that makes the mappings valid only when a specific address space identifier register is loaded. (See osSetTLBASID.) A value of -1
for asid specifies a global mapping that is always valid. For example, the following call specifies a global mapping of the virtual address range [0x2000, 0x3000] to the physical address range [0xab000, 0xac000] and the virtual address range [0x3000, 0x4000] to the physical address
range [0xcd000, 0xce000]:
osMapTLB(0, (void *)0x2000, 0xab000, 0xcd000, -1);
See Also
osMapTLB
osUnmapTLB
osUnmapTLBAll
osSetTLBASID
osVirtualToPhysical
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Nintendo® Confidential Warning: all information in this document is confidential and covered by a non-disclosure agreement. You are responsible for keeping this information confidential and protected. Nintendo will vigorously enforce this responsibility. Copyright © 1998 Nintendo of America Inc. All rights reserved Nintendo and N64 are registered trademarks of Nintendo Last updated March 1998 |