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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 Address + ∆
Note: ∆ is 1 for byte GPRs, ∆ is 2 for word GPRs.
Mnemonic Physical Address
Rw
(CP)
Rb
(CP)
reg
00'FE00
00'F000
(CP)
(CP)
bitoff
00'FD00
00'FF00
(CP)
bitaddr
Word offset as with bitoff.
Immediate bit position.
*)
The Extended Special Function Register (ESFR) area is not available in the SAB 8XC166(W)
devices.
Semiconductor Group
30Mar98@15:00h
+ 2*Rw
+ 1*Rb
+ 2*reg
H
*)
+ 2*reg
H
+ 2*(reg∧0F
)
H
+ 1*(reg∧0F
)
H
+ 2*bitoff
H
+ 2*(bitoff∧FF
)
H
H
+ 2*(bitoff∧0F
)
H
C166 Family Instruction Set
Short Address
*
Short Address Range Scope of Access
Rw
= 0...15
Rb
= 0...15
reg
= 00
...EF
H
H
reg
= 00
...EF
H
H
reg
= F0
...FF
H
H
reg
= F0
...FF
H
H
bitoff
= 00
...7F
H
H
bitoff
= 80
...EF
H
H
bitoff
= F0
...FF
H
H
bitoff
= 00
...FF
H
H
bitpos
= 0...15
116
Addressing Modes
GPRs (Word)
GPRs (Byte)
SFRs
(Word, Low byte)
ESFRs (Word, Low byte)
GPRs (Word)
GPRs (Bytes)
RAM
Bit word offset
SFR
Bit word offset
GPR
Bit word offset
Any single bit
Version 1.2, 12.97
*)
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