PIC17C7XX_13 Datasheet, PDF (198/306 Pages) Microchip Technology – High-Performance 8-bit CMOS EPROM Microcontrollers with 10-bit A/D

PIC17C7XX
Table 18-2 lists the instructions recognized by the
MPASM assembler.
Note 1: Any unused opcode is Reserved. Use of
any reserved opcode may cause unex-
pected operation.
All instruction examples use the following format to rep-
resent a hexadecimal number:
0xhh
where h signifies a hexadecimal digit.
To represent a binary number:
0000 0100b
where b signifies a binary string.
FIGURE 18-1:
GENERAL FORMAT FOR
INSTRUCTIONS
Byte-oriented file register operations
15
9 87
0
OPCODE
d
f (FILE #)
d = 0 for destination WREG
d = 1 for destination f
f = 8-bit file register address
Byte to Byte move operations
15
13 12
87
0
OPCODE p (FILE #)
f (FILE #)
p = peripheral register file address
f = 8-bit file register address
Bit-oriented file register operations
15
11 10 8 7
0
OPCODE
b (BIT #) f (FILE #)
b = 3-bit address
f = 8-bit file register address
Literal and control operations
15
OPCODE
87
0
k (literal)
k = 8-bit immediate value
CALL and GOTO operations
15
13 12
OPCODE
0
k (literal)
k = 13-bit immediate value
18.1 Special Function Registers as
Source/Destination
The PIC17C7XX’s orthogonal instruction set allows
read and write of all file registers, including special
function registers. There are some special situations
the user should be aware of:
18.1.1 ALUSTA AS DESTINATION
If an instruction writes to ALUSTA, the Z, C, DC and OV
bits may be set or cleared as a result of the instruction
and overwrite the original data bits written. For exam-
ple, executing CLRF ALUSTA will clear register
ALUSTA and then set the Z bit leaving 0000 0100b in
the register.
18.1.2 PCL AS SOURCE OR DESTINATION
Read, write or read-modify-write on PCL may have the
following results:
Read PC:
PCH  PCLATH; PCL  dest
Write PCL:
PCLATH  PCH;
8-bit destination value  PCL
Read-Modify-Write: PCL ALU operand
PCLATH  PCH;
8-bit result  PCL
Where PCH = program counter high byte (not an
addressable register), PCLATH = Program counter
high holding latch, dest = destination, WREG or f.
18.1.3 BIT MANIPULATION
All bit manipulation instructions are done by first read-
ing the entire register, operating on the selected bit and
writing the result back (read-modify-write (R-M-W)).
The user should keep this in mind when operating on
some special function registers, such as ports.
Note:
Status bits that are manipulated by the
device (including the interrupt flag bits) are
set or cleared in the Q1 cycle. So, there is
no issue on doing R-M-W instructions on
registers which contain these bits
DS30289C-page 198
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