A-3 Dsp56K Addressing Mode Encoding - Motorola DSP56000 Manual

Table A-3 DSP56K Addressing Mode Encoding
Addressing Mode
Data or Control Register
Address Register
Address Offset Register
Address Modifier Register
No Update
Postincrement by 1
Postdecrement by 1
Postincrement by Offset Nn
Postdecrement by Offset Nn
Indexed by Offset Nn
Predecrement by 1
Immediate Data
Absolute Address
Immediate Short Data
Short Jump Address
Absolute Short Address
I/O Short Address
Implicit
Update Mode (U)
Parallel Mode (P)
Memory Mode (M)
Alterable Mode (A) – Refers to alterable or writable registers or memory.
A - 12
ADDRESSING MODES
Mode Reg
MMM RRR
Register Direct
— —
— —
— —
— —
Address Register Indirect
100 Rn
011 Rn
010 Rn
001 Rn
000 Rn
101 Rn
111 Rn
Special
110 100
110 000
— —
— —
— —
— —
— —
– Modifies address registers without any associated data move.
– Used in instructions where two effective addresses are required.
– Refers to operands in memory using an effective addressing field.
INSTRUCTION SET DETAILS
Addressing Categories
U P M A
X
X
X
X
X X X
X X X X
X X X X
X X X X
X X X
X X
X X
X
X X
X
X
X
X
Assembler
Syntax
(See Table A-1)
Rn
Nn
Mn
(Rn)
(Rn) +
(Rn) -
(Rn) + Nn
(RN) - Nn
(Rn + Nn)
- (Rn)
#xxxxxx
xxxx
#xx
xxx
aa
pp
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