Datasheet

dsPIC33FJXXXMCX06/X08/X10
DS70287C-page 262 © 2009 Microchip Technology Inc.
All instructions are a single word, except for certain
double-word instructions, which were made
double-word instructions so that all the required infor-
mation is available in these 48 bits. In the second word,
the 8 MSbs are ‘0’s. If this second word is executed as
an instruction (by itself), it will execute as a NOP.
Most single-word instructions are executed in a single
instruction cycle, unless a conditional test is true, or the
program counter is changed as a result of the instruc-
tion. In these cases, the execution takes two instruction
cycles with the additional instruction cycle(s) executed
as a NOP. Notable exceptions are the BRA (uncondi-
tional/computed branch), indirect CALL/GOTO, all table
reads and writes and RETURN/RETFIE instructions,
which are single-word instructions but take two or three
cycles. Certain instructions that involve skipping over the
subsequent instruction require either two or three cycles
if the skip is performed, depending on whether the
instruction being skipped is a single-word or two-word
instruction. Moreover, double-word moves require two
cycles. The double-word instructions execute in two
instruction cycles.
Note: For more details on the instruction set,
refer to the “dsPIC30F/33F Programmer’s
Reference Manual” (DS70157).
TABLE 24-1: SYMBOLS USED IN OPCODE DESCRIPTIONS
Field Description
#text Means literal defined by “text”
(text) Means “content of text”
[text] Means “the location addressed by text”
{ } Optional field or operation
<n:m> Register bit field
.b Byte mode selection
.d Double-Word mode selection
.S Shadow register select
.w Word mode selection (default)
Acc One of two accumulators {A, B}
AWB Accumulator write back destination address register ∈ {W13, [W13]+ = 2}
bit4 4-bit bit selection field (used in word addressed instructions) ∈ {0...15}
C, DC, N, OV, Z MCU Status bits: Carry, Digit Carry, Negative, Overflow, Sticky Zero
Expr Absolute address, label or expression (resolved by the linker)
f File register address ∈ {0x0000...0x1FFF}
lit1 1-bit unsigned literal ∈ {0,1}
lit4 4-bit unsigned literal ∈ {0...15}
lit5 5-bit unsigned literal ∈ {0...31}
lit8 8-bit unsigned literal ∈ {0...255}
lit10 10-bit unsigned literal ∈ {0...255} for Byte mode, {0:1023} for Word mode
lit14 14-bit unsigned literal ∈ {0...16384}
lit16 16-bit unsigned literal ∈ {0...65535}
lit23 23-bit unsigned literal ∈ {0...8388608}; LSb must be ‘0’
None Field does not require an entry, may be blank
OA, OB, SA, SB DSP Status bits: AccA Overflow, AccB Overflow, AccA Saturate, AccB Saturate
PC Program Counter
Slit10 10-bit signed literal ∈ {-512...511}
Slit16 16-bit signed literal ∈ {-32768...32767}
Slit6 6-bit signed literal ∈ {-16...16}
Wb Base W register ∈ {W0..W15}
Wd Destination W register ∈ { Wd, [Wd], [Wd++], [Wd--], [++Wd], [--Wd] }
Wdo Destination W register ∈ { Wnd, [Wnd], [Wnd++], [Wnd--], [++Wnd], [--Wnd], [Wnd+Wb] }
Wm,Wn Dividend, Divisor working register pair (direct addressing)
Wm*Wm Multiplicand and Multiplier working register pair for Square instructions ∈
{W4 * W4,W5 * W5,W6 * W6,W7 * W7}