PIC18F2455_07 Datasheet, PDF (324/430 Pages) Microchip Technology – 28/40/44-Pin, High Performance, Enhanced Flash, USB Microcontrollers with nanoWatt Technology

PIC18F2455/2550/4455/4550
BZ
Branch if Zero
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
BZ n
-128 ≤ n ≤ 127
if Zero bit is ‘1’
(PC) + 2 + 2n → PC
None
1110 0000 nnnn nnnn
If the Zero bit is ‘1’, then the program
will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
1
Cycles:
Q Cycle Activity:
If Jump:
Q1
Decode
No
operation
If No Jump:
Q1
Decode
1(2)
Q2
Read literal
‘n’
No
operation
Q2
Read literal
‘n’
Q3
Process
Data
No
operation
Q3
Process
Data
Q4
Write to PC
No
operation
Q4
No
operation
Example:
HERE
Before Instruction
PC
=
After Instruction
If Zero
=
PC
=
If Zero
=
PC
=
BZ Jump
address (HERE)
1;
address (Jump)
0;
address (HERE + 2)
CALL
Subroutine Call
Syntax:
CALL k {,s}
Operands:
0 ≤ k ≤ 1048575
s ∈ [0,1]
Operation:
(PC) + 4 → TOS,
k → PC<20:1>,
if s = 1
(W) → WS,
(STATUS) → STATUSS,
(BSR) → BSRS
Status Affected:
None
Encoding:
1st word (k<7:0>)
2nd word(k<19:8>)
Description:
1110 110s k₇kkk kkkk₀
1111 k₁₉kkk kkkk kkkk₈
Subroutine call of entire 2-Mbyte
memory range. First, return address
(PC + 4) is pushed onto the return
stack. If ‘s’ = 1, the W, STATUS and
BSR
registers are also pushed into their
respective shadow registers, WS,
STATUSS and BSRS. If ‘s’ = 0, no
update occurs (default). Then, the
20-bit value ‘k’ is loaded into PC<20:1>.
CALL is a two-cycle instruction.
Words:
2
Cycles:
2
Q Cycle Activity:
Q1
Decode
No
operation
Q2
Read literal
‘k’<7:0>,
No
operation
Q3
Push PC to
stack
No
operation
Q4
Read literal
‘k’<19:8>,
Write to PC
No
operation
Example:
HERE
CALL THERE,1
Before Instruction
PC
=
After Instruction
PC
=
TOS
=
WS
=
BSRS =
STATUSS =
address (HERE)
address (THERE)
address (HERE + 4)
W
BSR
STATUS
DS39632D-page 322
Preliminary
© 2007 Microchip Technology Inc.