PIC12C5XX
All instructions are executed within a single instruction
cycle, unless a conditional test is true or the program
counter is changed as a result of an instruction. In this
case, the execution takes two instruction cycles. One
instruction cycle consists of four oscillator periods.
Thus, for an oscillator frequency of 4 MHz, the normal
instruction execution time is 1 µs. If a conditional test is
true or the program counter is changed as a result of
an instruction, the instruction execution time is 2 µs.
9.0
INSTRUCTION SET SUMMARY
Each PIC12C5XX instruction is a 12-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 PIC12C5XX
instruction set summary in Table 9-2 groups the
instructions into byte-oriented, bit-oriented, and literal
and control operations. Table 9-1 shows the opcode
field descriptions.
Figure 9-1 shows the three general formats that the
instructions can have. All examples in the figure use the
following format to represent a hexadecimal number:
For byte-oriented instructions, ’f’ represents a file
register designator and ’d’ represents a destination
designator. The file register designator is used to
specify which one of the 32 file registers is to be used
by the instruction.
0xhhh
where ’h’ signifies a hexadecimal digit.
The destination designator specifies where the result
of the operation is to be placed. If ’d’ is ’0’, the result is
placed in the W register. If ’d’ is ’1’, the result is placed
in the file register specified in the instruction.
FIGURE 9-1: GENERAL FORMAT FOR
INSTRUCTIONS
Byte-oriented file register operations
11
6
5
4
0
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.
OPCODE
d
f (FILE #)
d = 0 for destination W
d = 1 for destination f
f = 5-bit file register address
Bit-oriented file register operations
11 8 7
b (BIT #)
For literal and control operations, ’k’ represents an
8 or 9-bit constant or literal value.
5
4
0
TABLE 9-1:
OPCODE FIELD
DESCRIPTIONS
OPCODE
f (FILE #)
b = 3-bit bit address
f = 5-bit file register address
Field
Description
f
W
b
k
Register file address (0x00 to 0x7F)
Working register (accumulator)
Literal and control operations (except GOTO)
11
8
7
0
Bit address within an 8-bit file register
Literal field, constant data or label
OPCODE
k (literal)
k = 8-bit immediate value
Don’t care location (= 0 or 1)
The assembler will generate code with x = 0. It is
the recommended form of use for compatibility
with all Microchip software tools.
Literal and control operations - GOTOinstruction
11 0
x
d
9
8
OPCODE
k (literal)
Destination select;
d = 0 (store result in W)
d = 1 (store result in file register ’f’)
Default is d = 1
k = 9-bit immediate value
label Label name
TOS
PC
Top of Stack
Program Counter
Watchdog Timer Counter
Time-Out bit
WDT
TO
PD
Power-Down bit
Destination, either the W register or the specified
register file location
dest
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1999 Microchip Technology Inc.
DS40139E-page 47
MICROCHIP [ MICROCHIP ]
