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30Mar98@15:00h
Semiconductor Group
116
Version 1.2, 12.97
C166 Family Instruction Set
Addressing Modes
6
Addressing Modes
The Siemens 16-bit microcontrollers provide a lot of powerful addressing modes for access to word,
byte and bit data (short, long, indirect), or to specify the target address of a branch instruction
(absolute, relative, indirect). The different addressing modes use different formats and cover
different scopes.
Short Addressing Modes
All of these addressing modes use an implicit base offset address to specify an 18-bit or 24-bit
physical address (SAB 80C166 group or C167/5 group, respectively).
Short addressing modes allow to access the GPR, SFR or bit-addressable memory space:
Physical Address = Base A
∆
*
Short Address
Note:
∆
is 1 for byte GPRs,
∆
is 2 for word GPRs.
*)
The Extended Special Function Register (ESFR) area is not available in the SAB 8XC166(W)
devices.
Mnemonic
Physical Address
Short Address Range Scope of Access
Rw
(CP)
+ 2*Rw
Rw
= 0...15
GPRs
(Word)
Rb
(CP)
+ 1*Rb
Rb
= 0...15
GPRs
(Byte)
reg
00’FE00
H
+ 2*reg
00’F000
H
+ 2*reg
*)
(CP)
+ 2*(reg
∧
0F
H
)
(CP)
+ 1*(reg
∧
0F
H
)
reg
= 00
H
...EF
H
reg
= 00
H
...EF
H
reg
= F0
H
...FF
H
reg
= F0
H
...FF
H
SFRs
(Word, Low byte)
ESFRs (Word, Low byte)
*)
GPRs
(Word)
GPRs
(Bytes)
bitoff
00’FD00
H
+ 2*bitoff
00’FF00
H
+ 2*(bitoff
∧
FF
H
)
(CP)
+ 2*(bitoff
∧
0F
H
)
bitoff
= 00
H
...7F
H
bitoff
= 80
H
...EF
H
bitoff
= F0
H
...FF
H
RAM
Bit word offset
SFR
Bit word offset
GPR
Bit word offset
bitaddr
Word offset as with bitoff.
Immediate bit position.
bitoff
= 00
H
...FF
H
bitpos
= 0...15
Any single bit