PIC18F2220/2320/4220/4320
MULLW
Multiply Literal with W
MULWF
Multiply W with f
Syntax:
[ label ] MULLW
0 ≤ k ≤ 255
k
Syntax:
[ label ] MULWF f [,a]
Operands:
Operation:
Status Affected:
Encoding:
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
(W) x k → PRODH:PRODL
Operation:
(W) x (f) → PRODH:PRODL
None
Status Affected:
Encoding:
None
0000
1101
kkkk
kkkk
0000
001a
ffff
ffff
Description:
An unsigned multiplication is
carried out between the contents
of W and the 8-bit literal ‘k’. The
16-bit result is placed in
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 opera-
tion. A zero result is possible but
not detected.
Description:
An unsigned multiplication is
carried out between the contents
of W and the register file location
‘f’. The 16-bit result is stored in
the PRODH:PRODL register
pair. PRODH contains the high
byte.
Both W and ‘f’ are unchanged.
None of the status flags are
affected.
Note that neither overflow nor
carry is possible in this opera-
tion. A zero result is possible but
not detected. If ‘a’ is ‘0’, the
Access Bank will be selected,
overriding the BSR value. If
‘a’= 1, then the bank will be
selected as per the BSR value
(default).
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write
registers
PRODH:
PRODL
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
MULLW
0xC4
Example:
Q2
Q3
Q4
Before Instruction
Decode
Read
register ‘f’
Process
Data
Write
W
PRODH
PRODL
=
=
=
0xE2
registers
PRODH:
PRODL
?
?
After Instruction
W
=
0xE2
0xAD
0x08
MULWF
REG
Example:
PRODH
PRODL
=
=
Before Instruction
W
=
0xC4
REG
PRODH
PRODL
=
=
=
0xB5
?
?
After Instruction
W
=
0xC4
REG
PRODH
PRODL
=
=
=
0xB5
0x8A
0x94
DS39599C-page 282
2003 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
