Section 2 CPU
Rev. 3.00 Sep. 27, 2007 Page 19 of 758
REJ09B0243-0300
2.2.1
General Registers (Rn)
There are sixteen 32-bit general registers (Rn), designated R0 to R15. The general registers are
used for data processing and address calculation. R0 is also used as an index register. With a
number of instructions, R0 is the only register that can be used. R15 is used as a hardware stack
pointer (SP). In exception handling, R15 is used for accessing the stack to save or restore the
status register (SR) and program counter (PC) values.
2.2.2 Control
Registers
There are three 32-bit control registers, designated status register (SR), global base register
(GBR), and vector base register (VBR). SR indicates a processing state. GBR is used as a base
address in GBR indirect addressing mode for data transfer of on-chip peripheral module registers.
VBR is used as a base address of the exception handling (including interrupts) vector table.
•
Status register (SR)
Bit:
Initial value:
R/W:
Bit:
Initial value:
R/W:
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
0
0
0
0
0
0
-
-
1
1
1
1
0
0
-
-
R
R
R
R
R
R
R/W
R/W
R/W
R/W
R/W
R/W
R
R
R/W
R/W
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
M
Q
I[3:0]
-
-
S
T
Bit
Bit
name
Default
Read/
Write
Description
31 to 10
All
0
R Reserved
These bits are always read as 0. The write value
should always be 0.
9
M
Undefined
R/W
Used by the DIV0U, DIV0S, and DIV1 instructions.
8
Q
Undefined
R/W
Used by the DIV0U, DIV0S, and DIV1 instructions.
7 to 4
I[3:0]
1111
R/W
Interrupt Mask
3, 2
All
0
R Reserved
These bits are always read as 0. The write value
should always be 0.
Summary of Contents for SH7124 R5F7124
Page 2: ...Rev 3 00 Sep 27 2007 Page ii of xx ...
Page 8: ...Rev 3 00 Sep 27 2007 Page viii of xx ...
Page 36: ...Section 1 Overview Rev 3 00 Sep 27 2007 Page 16 of 758 REJ09B0243 0300 ...
Page 68: ...Section 2 CPU Rev 3 00 Sep 27 2007 Page 48 of 758 REJ09B0243 0300 ...
Page 108: ...Section 5 Exception Handling Rev 3 00 Sep 27 2007 Page 88 of 758 REJ09B0243 0300 ...
Page 166: ...Section 7 User Break Controller UBC Rev 3 00 Sep 27 2007 Page 146 of 758 REJ09B0243 0300 ...
Page 724: ...Section 20 List of Registers Rev 3 00 Sep 27 2007 Page 704 of 758 REJ09B0243 0300 ...
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