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Section 2 CPU
2.5
Registers
The H8SX CPU has the internal registers shown in figure 2.9. There are two types of registers:
general registers and control registers. The control registers are the 32-bit program counter (PC),
8-bit extended control register (EXR), 8-bit condition-code register (CCR), 32-bit vector base
register (VBR), 32-bit short address base register (SBR), and 64-bit multiply-accumulate register
(MAC).
General Registers and Extended Registers
ER0
ER1
ER2
ER3
ER4
ER5
ER6
ER7 (SP)
Control Registers
VBR
SBR
MAC
[Legend]
SP:
PC:
CCR:
I:
UI:
H:
U:
N:
Rev.2.00 Jun. 28, 2007 Page 24 of 666
REJ09B0311-0200
15
E0
E1
E2
E3
E4
E5
E6
E7
31
PC
31
31
63
Sign extension
31
Stack pointer
Program counter
Condition-code register
Interrupt mask bit
User bit or interrupt mask bit
Half-carry flag
User bit
Negative flag
Figure 2.9 CPU Registers
0 7
0 7
R0H
R1H
R2H
R3H
R4H
R5H
R6H
R7H
7 6 5 4 3 2 1 0
CCR
I UI H U N Z V C
7 6 5 4 3 2 1 0
EXR
T — — — — I2 I1 I0
12
(Reserved)
8
41
MACL
Z:
Zero flag
V:
Overflow flag
C:
Carry flag
EXR:
Extended control register
T:
Trace bit
I2 to I0:
Interrupt mask bits
VBR:
Vector base register
SBR:
Short address base register
MAC:
Multiply-accumulate register
0
R0L
R1L
R2L
R3L
R4L
R5L
R6L
R7L
0
0
0
(Reserved)
32
MACH
0
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