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PIC17C4X Datasheet, PDF (129/240 Pages) Microchip Technology – High-Performance 8-Bit CMOS EPROM/ROM Microcontroller | |||
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PIC17C4X
MULLW
Multiply Literal with WREG
Syntax:
[ label ] MULLW k
Operands:
0 ⤠k ⤠255
Operation:
(k x WREG) â PRODH:PRODL
Status Affected: None
Encoding:
1011 1100 kkkk kkkk
Description:
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 ï¬ags are affected.
Note that neither overï¬ow nor carry
is possible in this operation. A zero
result is possible but not detected.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Read
literal 'k'
Q3
Execute
Example:
MULLW 0xC4
Q4
Write
registers
PRODH:
PRODL
Before Instruction
WREG
=
PRODH
=
PRODL
=
0xE2
?
?
After Instruction
WREG
=
PRODH
=
PRODL
=
0xC4
0xAD
0x08
Note: This instruction is not available in the
PIC17C42 device.
MULWF
Multiply WREG with f
Syntax:
[ label ] MULWF f
Operands:
0 ⤠f ⤠255
Operation:
(WREG x f) â PRODH:PRODL
Status Affected: None
Encoding:
0011 0100 ffff ffff
Description:
An unsigned multiplication is carried
out between the contents of WREG
and the register ï¬le 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 ï¬ags are affected.
Note that neither overï¬ow nor carry
is possible in this operation. A zero
result is possible but not detected.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Read
register 'f'
Q3
Execute
Example:
MULWF REG
Q4
Write
registers
PRODH:
PRODL
Before Instruction
WREG
=
REG
=
PRODH
=
PRODL
=
0xC4
0xB5
?
?
After Instruction
WREG
=
REG
=
PRODH
=
PRODL
=
0xC4
0xB5
0x8A
0x94
Note: This instruction is not available in the
PIC17C42 device.
© 1996 Microchip Technology Inc.
DS30412C-page 129
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