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PIC18F4580 Datasheet, PDF (390/484 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology | |||
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PIC18F2480/2580/4480/4580
MULLW
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
Q1
Decode
Multiply Literal with W
MULLW k
0 ⤠k ⤠255
(W) x k â PRODH:PRODL
None
0000 1101 kkkk kkkk
An unsigned multiplication is carried
out between the contents of W and the
8-bit literal âkâ. The 16-bit result is
placed in the PRODH:PRODL register
pair. PRODH contains the high byte.
W is unchanged.
None of the status flags are affected.
Note that neither overflow nor carry is
possible in this operation. A zero result
is possible but not detected.
1
1
Q2
Read
literal âkâ
Q3
Process
Data
Q4
Write
registers
PRODH:
PRODL
Example:
MULLW 0C4h
Before Instruction
W
PRODH
PRODL
= E2h
=?
=?
After Instruction
W
PRODH
PRODL
= E2h
= ADh
= 08h
MULWF
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
Q1
Decode
Multiply W with f
MULWF f {,a}
0 ⤠f ⤠255
a â [0,1]
(W) x (f) â PRODH:PRODL
None
0000 001a ffff ffff
An unsigned multiplication is carried
out between the contents of W and the
register file location âfâ. The 16-bit
result is stored in the PRODH:PRODL
register pair. PRODH contains the
high byte. Both W and âfâ are
unchanged.
None of the status flags are affected.
Note that neither overflow nor carry is
possible in this operation. A zero
result is possible but not detected.
If âaâ is â0â, the Access Bank is
selected. If âaâ is â1â, the BSR is used
to select the GPR bank (default).
If âaâ is â0â and the extended
instruction set is enabled, this
instruction operates in Indexed Literal
Offset Addressing mode whenever
f ⤠95 (5Fh). See Section 25.2.3
âByte-Oriented and Bit-Oriented
Instructions in Indexed Literal Offset
Modeâ for details.
1
1
Q2
Read
register âfâ
Q3
Process
Data
Q4
Write
registers
PRODH:
PRODL
Example:
MULWF REG, 1
Before Instruction
W
REG
PRODH
PRODL
= C4h
= B5h
=?
=?
After Instruction
W
REG
PRODH
PRODL
= C4h
= B5h
= 8Ah
= 94h
DS39637A-page 388
Preliminary
 2004 Microchip Technology Inc.
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