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2006 Microchip Technology Inc.
DS70117F-page 39
dsPIC30F6011/6012/6013/6014
4.0
ADDRESS GENERATOR UNITS
The dsPIC DSC core contains two independent
address generator units: the X AGU and Y AGU. The Y
AGU supports word-sized data reads for the DSP MAC
class of instructions only. The dsPIC30F AGUs
support:
Linear Addressing
Modulo (Circular) Addressing
Bit-Reversed Addressing
Linear and Modulo Data Addressing modes can be
applied to data space or program space. Bit-Reversed
Addressing is only applicable to data space addresses.
4.1
Instruction Addressing Modes
The addressing modes in
Table 4-1 form the basis of
the addressing modes optimized to support the specific
features of individual instructions. The addressing
modes provided in the MAC class of instructions are
somewhat different from those in the other instruction
types.
4.1.1
FILE REGISTER INSTRUCTIONS
Most File register instructions use a 13-bit address field
(f) to directly address data present in the first 8192
bytes of data memory (Near data space). Most File
register instructions employ a working register, W0,
which is denoted as WREG in these instructions. The
destination is typically either the same File register or
WREG (with the exception of the MUL instruction),
which writes the result to a register or register pair. The
MOV
instruction allows additional flexibility and can
access the entire data space.
4.1.2
MCU INSTRUCTIONS
The three-operand MCU instructions are of the form:
Operand 3 = Operand 1 <function> Operand 2
where Operand 1 is always a working register (i.e., the
Addressing mode can only be Register Direct) which is
referred to as Wb. Operand 2 can be a W register,
fetched from data memory or a 5-bit literal. The result
location can be either a W register or a data memory
location.
The
following
addressing
modes
are
supported by MCU instructions:
Register Direct
Register Indirect
Register Indirect Post-modified
Register Indirect Pre-modified
5-bit or 10-bit Literal
TABLE 4-1:
FUNDAMENTAL ADDRESSING MODES SUPPORTED
Note: This data sheet summarizes features of this group
of dsPIC30F devices and is not intended to be a complete
reference source. For more information on the CPU,
peripherals, register descriptions and general device
functionality, refer to the “dsPIC30F Family Reference
Manual” (DS70046). For more information on the device
instruction set and programming, refer to the “dsPIC30F/
33F Programmer’s Reference Manual” (DS70157).
Note:
Not all instructions support all the address-
ing modes given above. Individual instruc-
tions may support different subsets of
these addressing modes.
Addressing Mode
Description
File Register Direct
The address of the File register is specified explicitly.
Register Direct
The contents of a register are accessed directly.
Register Indirect
The contents of Wn forms the EA.
Register Indirect Post-modified
The contents of Wn forms the EA. Wn is post-modified (incremented or
decremented) by a constant value.
Register Indirect Pre-modified
Wn is pre-modified (incremented or decremented) by a signed constant value
to form the EA.
Register Indirect with Register Offset The sum of Wn and Wb forms the EA.
Register Indirect with Literal Offset
The sum of Wn and a literal forms the EA.