Datasheet

dsPIC33FJXXXGPX06A/X08A/X10A
DS70593D-page 68  2009-2012 Microchip Technology Inc.
ister or WREG (with the exception of the MUL instruc-
tion), which writes the result to a register or register
pair. The MOV instruction allows additional flexibility and
can access the entire data space.
4.3.2 MCU INSTRUCTIONS
The 3-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 4-35: FUNDAMENTAL ADDRESSING MODES SUPPORTED
4.3.3 MOVE AND ACCUMULATOR
INSTRUCTIONS
Move instructions and the DSP accumulator class of
instructions provide a greater degree of addressing
flexibility than other instructions. In addition to the
Addressing modes supported by most MCU
instructions, move and accumulator instructions also
support Register Indirect with Register Offset
Addressing mode, also referred to as Register Indexed
mode.
In summary, the following Addressing modes are
supported by move and accumulator instructions:
• Register Direct
• Register Indirect
• Register Indirect Post-modified
• Register Indirect Pre-modified
• Register Indirect with Register Offset (Indexed)
• Register Indirect with Literal Offset
• 8-bit Literal
• 16-bit Literal
4.3.4 MAC INSTRUCTIONS
The dual source operand DSP instructions (CLR, ED,
EDAC, MAC, MPY, MPY.N, MOVSAC and MSC), also referred
to as MAC instructions, utilize a simplified set of
addressing modes to allow the user to effectively
manipulate the data pointers through register indirect
tables.
The 2-source operand prefetch registers must be
members of the set {W8, W9, W10, W11}. For data
reads, W8 and W9 are always directed to the X RAGU
and W10 and W11 will always be directed to the Y
AGU. The effective addresses generated (before and
Note: Not all instructions support all the
addressing modes given above.
Individual instructions 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.
Note: For the MOV instructions, the Addressing
mode specified in the instruction can differ
for the source and destination EA.
However, the 4-bit Wb (Register Offset)
field is shared between both source and
destination (but typically only used by
one).
Note: Not all instructions support all the
Addressing modes given above.
Individual instructions may support
different subsets of these Addressing
modes.