SH7055S Datasheet, PDF (66/1002 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series

2.1.2 Control Registers
The 32-bit control registers consist of the 32-bit status register (SR), global base register (GBR),
and vector base register (VBR). The status register indicates processing states. The global base
register functions as a base address for the indirect GBR addressing mode to transfer data to the
registers of on-chip peripheral modules. The vector base register functions as the base address of
the exception processing vector area (including interrupts). Figure 2.2 shows the control registers.
31
SR
31
31
9 8 7 6 5 4 321 0
M Q I3 I2 I1 I0 S T SR: Status register
T bit: The MOVT, CMP/cond, TAS, TST,
BT (BT/S), BF (BF/S), SETT, CLRT, and
FCMP/cond instructions use the T bit to
indicate true (1) or false (0). The ADDV,
ADDC, SUBV, SUBC, NEGC, DIV0U,
DIV0S, DIV1, SHAR, SHAL, SHLR, SHLL,
ROTR, ROTL, ROTCR, and ROTCL
instructions also use the T bit to indicate
carry/borrow or overflow/underflow.
S bit: Used by the MAC instruction.
Reserved bits. These bits always read 0.
The write value should always be 0.
Bits I3–I0: Interrupt mask bits.
M and Q bits: Used by the DIV0U, DIV0S,
and DIV1 instructions.
Reserved bits. These bits always read 0.
The write value should always be 0.
GBR
0 Global base register (GBR):
Indicates the base address of the indirect
GBR addressing mode. The indirect GBR
addressing mode is used in data transfer
for on-chip peripheral module register
areas and in logic operations.
VBR
0 Vector base register (VBR):
Stores the base address of the exception
processing vector area.
Figure 2.2 Control Register Configuration
Rev.2.0, 07/03, page 28 of 960