HD6417660 RENESAS [Renesas Technology Corp], HD6417660 Datasheet - Page 113

• Manufacturer Part Number: HD6417660
• Description: Renesas 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

3.2
3.2.1
The CPU processing modes can be extended using the mode bit (MD) and DSP bit (DSP) of the
status register (SR), as shown below.
As shown above, the extension of the DSP function by the DSP bit can be specified independently
of the control by the MD bit. Note, however, that the DSP bit can be modified only in privileged
mode. Before the DSP bit is modified, a transition to privileged mode or privileged DSP mode is
necessary.
3.2.2
In DSP mode, a part of the P2 area in the virtual address space can be accessed in user DSP mode
(H'A5000000 to H'A5FFFFFF of H'A0000000 to H'BFFFFFFF can be accessed) as shown in
figure 3.1. When this area is accessed in user DSP mode, this area is referred to as a Uxy area.
X/Y memory is then assigned to this Uxy area. Accordingly, X/Y memory can also be accessed in
user DSP mode.
Table 3.1
MD
Bit
0
0
1
1
Address Range
H'A5000000 to H'A5FFFFFF
DSP
Bit
0
1
0
1
DSP Mode Resources
Processing Modes
DSP Mode Memory Map
Virtual Address Space
Processing Mode
User mode
User DSP mode
Privileged mode
Privileged DSP mode Allowed
Name
P2/Uxy
Access of Resources
Protected in Privileged Mode
or Privileged Instruction
Execution
Prohibited
Prohibited
Allowed
Protection
Privileged mode
or DSP mode
Description
16-Mbyte physical address space,
non-cacheable
Can be accessed in privileged mode
and DSP modes (privileged DSP
mode and user DSP mode)
Description
Rev. 1.00, 02/04, page 75 of 804
DSP Extended
Functions
Invalid
Valid
Invalid
Valid