HD6417021 Hitachi Semiconductor, HD6417021 Datasheet - Page 35

• Manufacturer Part Number: HD6417021
• Description: SuperH RISC engine
• Manufacturer: Hitachi Semiconductor

functions as a base address for the indirect GBR addressing mode to transfer data to the registers
of peripheral on-chip modules. The vector base register functions as the base address of the
exception processing vector area including interrupts.
2.1.3
System registers consist of four 32-bit registers: multiply and accumulate registers high and low
(MACH and MACL), procedure register (PR), and program counter (PC). The multiply and
accumulate registers store the results of multiply and accumulate operations. The procedure
register stores the return address from the subroutine procedure. The program counter stores
program addresses to control the flow of the processing.
16 HITACHI
SR
31
31
31
System Registers
M Q I3 I2 I1 I0
9 8 7 6 5 4 3 2 1 0
GBR
VBR
Figure 2.2 Control Registers
S T
0
0
SR: Status register
T bit: The MOVT, CMP, TAS, TST,
S bit: Used by the MAC instruction.
Reserved bits. These bits always read 0.
The write value should always be 0.
Bits I0–I3: Interrupt mask bits.
M and Q bits: Used by the DIV0U, DIV0S,
Global base register (GBR):
Indicates the base address of the indirect
GBR addressing mode. The indirect GBR
addressing mode is used to transfer data
to the register areas peripheral on-chip
modules.
Vector base register (VBR):
Stores the base address of the exception
processing vector area.
BT, BF, SETT, and CLRT instructions
use the T bit to indicate a true (1) or
false (0). The ADDV, ADDC, SUBV,
SUBC, DIV0U, DIV0S, DIV1, NEGC,
SHAR, SHAL, SHLR, SHLL, ROTR,
ROTL, ROTCR and ROTCL
instructions also use the T bit to indicate
carry/borrow or overflow/underflow
and DIV1 instructions.