PIC17C75X Datasheet, PDF (205/320 Pages) Microchip Technology – High-Performance 8-Bit CMOS EPROM Microcontrollers

MULLW
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
Q1
Decode
Multiply Literal with WREG
[ label ] MULLW k
0 ≤ k ≤ 255
(k x WREG) → PRODH:PRODL
None
1011 1100 kkkk kkkk
An unsigned multiplication is carried
out between the contents of WREG
and the 8-bit literal 'k'. The 16-bit
result is placed in PRODH:PRODL
register pair. PRODH contains the
high byte.
WREG 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 'k'
Q3
Process
Data
Q4
Write
registers
PRODH:
PRODL
Example:
MULLW 0xC4
Before Instruction
WREG
=
PRODH
=
PRODL
=
0xE2
?
?
After Instruction
WREG
=
PRODH
=
PRODL
=
0xC4
0xAD
0x08
PIC17C75X
MULWF
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
Q1
Decode
Multiply WREG with f
[ label ] MULWF f
0 ≤ f ≤ 255
(WREG x f) → PRODH:PRODL
None
0011 0100 ffff ffff
An unsigned multiplication is carried
out between the contents of WREG
and the register file location 'f'. The
16-bit result is stored in the
PRODH:PRODL register pair.
PRODH contains the high byte.
Both WREG and 'f' 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.
1
1
Q2
Read
register 'f'
Q3
Process
Data
Q4
Write
registers
PRODH:
PRODL
Example:
MULWF REG
Before Instruction
WREG
=
REG
=
PRODH
=
PRODL
=
0xC4
0xB5
?
?
After Instruction
WREG
=
REG
=
PRODH
=
PRODL
=
0xC4
0xB5
0x8A
0x94
© 1997 Microchip Technology Inc.
DS30264A-page 205