HD6417706 RENESAS [Renesas Technology Corp], HD6417706 Datasheet - Page 99

• Manufacturer Part Number: HD6417706
• Description: Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

3.1.1
This LSI's MMU
Virtual Address Map: This LSI uses 32-bit virtual addresses to access a 4-Gbyte virtual address
space that is divided into several areas. Address space mapping is shown in figure 3.2.
In the privileged mode, the virtual address space is divided into five areas.
P0 and P3 areas are mapped to physical address spaces in page units according to the information
in the address translation table. Write-back or write-through can be selected for write access by
means of a cache control register (CCR) setting.
Mapping of the P1 area is fixed to physical address space (H'00000000 to H'1FFFFFFF). In the P1
area, setting a virtual address MSBs (bit 31) to 0 generates the corresponding physical address. P1
area access can be cached, write-back or write-through can be selected according to the setting of
CCR whether to cache or not.
Mapping of the P2 area is fixed to physical address space (H'00000000 to H'1FFFFFFF). In the P2
area, setting the top three virtual address bits (bits 31, 30, and 29) to 0 generates the corresponding
physical address. P2 area access cannot be cached.
The P1 and P2 areas are not mapped by the address translation table, so the TLB is not used and
no exceptions like TLB misses occur. Initialization of MMU-related registers, exception
processing, and the like are located in the P1 and P2 areas. Because the P1 area is cached, handlers
that require high-speed processing are placed there.
A part of the control register in the peripheral module is allocated in P2 area.
The P4 area is used for mapping on-chip control register addresses. Address spaces from
H'E0000000 to H'EFFFFFFF and from H'F4000000 to H'FBFFFFFF are reserved. An operation of
this LSI is not guaranteed when these address spaces are accessed. Address space from
H'F0000000 to H'F1FFFFFF is assigned to the cache, and address space from H'F2000000 to
H'F3FFFFFF is assigned to the TLB. Address space from H'FC000000 to H'FFFFFFFF is a space
for control registers. However, an operation of this LSI is not guaranteed when an address space
that is not assigned to any control register is accessed.
In the user mode, 2 Gbytes of the virtual address space from H'00000000 to H'7FFFFFFF (area
U0) can be accessed. U0 is mapped onto physical address space in page units. Write-back or write-
through mode can be selected for write accesses by means of CCR setting. 2 Gbytes of the virtual
address space from H'80000000 to H'FFFFFFFF cannot be accessed in the user mode. Attempting
to do so creates an CPU address error. Write-back or write-through can be selected for write
access by means of the CCR setting.
Rev. 4.00, 03/04, page 53 of 660