Table Base Register (Tbr) - Fujitsu FR60 Hardware Manual

CHAPTER 3 CPU AND CONTROL UNITS

3.10.4 Table Base Register (TBR)

The table base register (TBR: Table Base Register) indicates the beginning address of
the vector table for EIT.
■ Table Base Register (TBR)
The table base register (TBR) consists of 32 bits.
Figure 3.10-4 shows the configuration of table base register (TBR) bits.
TBR
Obtain a vector address by adding to the TBR the offset value predetermined for an EIT cause.
The table base register (TBR) is initialized to 000FFC00
■ EIT Vector Table
A 1 Kbyte area from the address indicated in the table base register (TBR) is the vector area for
EIT.
The size for each vector is 4 bytes. The relationship between a vector number and a vector
address can be expressed as follows:
vctadr = TBR + vctofs
= TBR + (3FC
vctadr: Vector address
vctofs: Vector offset
vct: Vector number
The low-order two bits of the addition result are always handled as "00
The area from 000FFC00
Special functions are allocated to some of the vectors.
84
Figure 3.10-4 Configuration of Table Base Register Bit
bit 31 . .
- 4 x vct)
H
to 000FFFFF
H
. . 0
by a reset.
H
is the initial area for the vector table upon reset.
H
[Initial value]
000FFC00
H
".
B