PIC16F87X
execution time is 1 µs. If a conditional test is true or the
program counter is changed as a result of an instruc-
tion, the instruction execution time is 2 µs.
13.0 INSTRUCTION SET SUMMARY
Each PIC16CXX instruction is a 14-bit word divided
into an OPCODE which specifies the instruction type
and one or more operands which further specify the
operation of the instruction. The PIC16CXX instruction
set summary in Table 13-2 lists byte-oriented, bit-ori-
ented, and literal and control operations. Table 13-1
shows the opcode field descriptions.
Table 13-2 lists the instructions recognized by the
MPASM assembler.
Figure 13-1 shows the general formats that the instruc-
tions can have.
Note: To maintain upward compatibility with
future PIC16CXX products, do not use the
OPTIONand TRISinstructions.
For byte-oriented instructions, ’f’ represents a file reg-
ister designator and ’d’ represents a destination desig-
nator. The file register designator specifies which file
register is to be used by the instruction.
All examples use the following format to represent a
hexadecimal number:
The destination designator specifies where the result of
the operation is to be placed. If ’d’ is zero, the result is
placed in the W register. If ’d’ is one, the result is placed
in the file register specified in the instruction.
0xhh
where h signifies a hexadecimal digit.
FIGURE 13-1: GENERAL FORMAT FOR
INSTRUCTIONS
For bit-oriented instructions, ’b’ represents a bit field
designator which selects the number of the bit affected
by the operation, while ’f’ represents the number of the
file in which the bit is located.
Byte-oriented file register operations
13
8
7
6
0
0
OPCODE
d
f (FILE #)
For literal and control operations, ’k’ represents an
eight or eleven bit constant or literal value.
d = 0 for destination W
d = 1 for destination f
f = 7-bit file register address
TABLE 13-1: OPCODE FIELD
DESCRIPTIONS
Bit-oriented file register operations
13 10 9
b (BIT #)
Field
Description
7
6
f
W
b
k
x
Register file address (0x00 to 0x7F)
Working register (accumulator)
OPCODE
f (FILE #)
b = 3-bit bit address
f = 7-bit file register address
Bit address within an 8-bit file register
Literal field, constant data or label
Literal and control operations
General
Don't care location (= 0or 1)
The assembler will generate code with x = 0. It
is the recommended form of use for compati-
bility with all Microchip software tools.
13
8
7
0
0
OPCODE
k (literal)
d
Destination select; d = 0: store result in W,
d = 1: store result in file register f.
Default is d = 1
k = 8-bit immediate value
PC
TO
PD
Program Counter
Time-out bit
CALL and GOTO instructions only
13 11 10
OPCODE
k = 11-bit immediate value
k (literal)
Power-down bit
The instruction set is highly orthogonal and is grouped
into three basic categories:
A description of each instruction is available in the
• Byte-oriented operations
• Bit-oriented operations
PICmicro™
(DS33023).
Mid-Range
Reference
Manual,
• Literal and control operations
All instructions are executed within one single instruc-
tion cycle, unless a conditional test is true or the pro-
gram counter is changed as a result of an instruction.
In this case, the execution takes two instruction cycles
with the second cycle executed as a NOP. One instruc-
tion cycle consists of four oscillator periods. Thus, for
an oscillator frequency of 4 MHz, the normal instruction
1999 Microchip Technology Inc.
DS30292B-page 137
MICROCHIP [ MICROCHIP ]
