User Manual
C166S V2
Central Processing Unit
User Manual
2-74
V 1.7, 2001-01
The MDRIU flag is the only portion of the MDC register used for multiplication and
division within the C166S V2 CPU. This bit indicates the usage of the MDL and MDH
register. It must be stored prior to a new multiplication or division operation. The
remaining portions of the MDC register are never used by the dedicated multiplication
and division hardware.
2.6.6
The Processor Status Word PSW
This bit addressable register reflects the current status of the microcontroller. Two
groups of bits represent the current ALU status and the current CPU interrupt status.
Two separate bits (USR0 and USR1) within register PSW are provided as general
purpose flags.
PSW
Processor Status Word
SFRb
Reset Value: 0000
H
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ILVL
IEN
HLD
EN
BANK
USR
1
USR
0
MUL
IP
E
Z
V
C
N
rwh
rw
rw
rwh
rwh
rwh
r
rwh
rwh
rwh
rwh
rwh
Field
Bits
Type Description
ILVL
[15:12] rwh
CPU Priority Level
0
H
Lowest Priority
...
...
F
H
Highest Priority
IEN
[11]
rw
Interrupt/PEC Enable Bit (globally)
0
Interrupt/PEC requests are disabled
1
Interrupt/PEC requests are enabled
HLDEN
[10]
rw
Hold Enable
0
external bus arbitration disabled
1
external bus arbitration enabled
BANK
[9:8]
rwh
Reserved for Register File Bank Selection
00
Global register bank
01
Reserved
10
Local register bank 1
11
Local register bank 2
USR1
[7]
rwh
General Purpose Flag
May be used by application
USR0
[6]
rwh
General Purpose Flag
May be used by application
Summary of Contents for C166S V2
Page 102: ...User Manual C166S V2 C166S V2 Memory Organization User Manual 3 102 V 1 7 2001 01...
Page 116: ...User Manual C166S V2 Instruction Pipeline User Manual 4 116 V 1 7 2001 01...
Page 152: ...User Manual C166S V2 Interrupt and Exception Handling User Manual 5 152 V 1 7 2001 01...
Page 204: ...User Manual C166S V2 Instruction Set User Manual 7 204 V 1 7 2001 01...
Page 420: ...User Manual C166S V2 Detailed Instruction Description User Manual 8 420 V 1 7 2001 01...
Page 432: ...User Manual C166S V2 Summary of CPU Subsystem Registers User Manual 9 432 V 1 7 2001 01...
Page 437: ...437...