PIC18F1220_07 Datasheet, PDF (220/308 Pages) Microchip Technology – 18/20/28-Pin High-Performance, Enhanced Flash Microcontrollers with 10-bit A/D and nanoWatt Technology

PIC18F1220/1320
MULLW
Multiply Literal with W
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
[ label ] MULLW k
0 ≤ k ≤ 255
(W) x k → PRODH:PRODL
None
0000 1101 kkkk kkkk
An unsigned multiplication is
carried out between the contents
of W and the 8-bit literal ‘k’. 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 opera-
tion. A Zero result is possible but
not detected.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Read
literal ‘k’
Q3
Process
Data
Q4
Write
registers
PRODH:
PRODL
Example:
MULLW 0xC4
Before Instruction
W
=
PRODH
=
PRODL
=
After Instruction
W
=
PRODH
=
PRODL
=
0xE2
?
?
0xE2
0xAD
0x08
MULWF
Multiply W with f
Syntax:
[ label ] MULWF f [,a]
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
(W) x (f) → PRODH:PRODL
Status Affected: None
Encoding:
0000 001a ffff ffff
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:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
registers
PRODH:
PRODL
Example:
MULWF REG
Before Instruction
W
=
REG
=
PRODH
=
PRODL
=
After Instruction
W
=
REG
=
PRODH
=
PRODL
=
0xC4
0xB5
?
?
0xC4
0xB5
0x8A
0x94
DS39605F-page 218
© 2007 Microchip Technology Inc.