Vault 7: Projects

This publication series is about specific projects related to the Vault 7 main publication.

© 2005-2011 Microchip Technology Inc. DS70157F-page 303
Section 5. Instruction Descriptions
Instruction
Descriptions
5
MUL
Integer Unsigned Multiply f and WREG
Implemented in: PIC24F PIC24H PIC24E dsPIC30F dsPIC33F dsPIC33E
X X X X X X
Syntax: {label:} MUL{.B} f
Operands: f [0 ... 8191]
Operation: For byte operation:
(WREG)<7:0> * (f)<7:0> W2
For word operation:
(WREG) * (f) W2:W3
Status Affected: None
Encoding:
1011 1100 0B0f ffff ffff ffff
Description: Multiply the default working register WREG with the specified file
register and place the result in the W2:W3 register pair. Both operands
and the result are interpreted as unsigned integers. If this instruction is
executed in Byte mode, the 16-bit result is stored in W2. In Word mode,
the most significant word of the 32-bit result is stored in W3, and the
least significant word of the 32-bit result is stored in W2.
The ‘B’ bit selects byte or word operation (‘0’ for word, ‘1’ for byte).
The ‘f’ bits select the address of the file register.
Note 1: The extension .B in the instruction denotes a byte operation
rather than a word operation. You may use a .W extension to
denote a word operation, but it is not required.
2: The WREG is set to working register W0.
3: The IF bit (CORCON<0>), has no effect on this operation.
4: This is the only instruction, which provides for an 8-bit
multiply.
Words: 1
Cycles:
1
(1)
Note 1:
In dsPIC33E and PIC24E devices, the listed cycle count does not apply to read and
read-modify-write operations on non-CPU Special Function Registers. For more
details, see
Note 3
in
Section 3.2.1 “Multi-Cycle Instructions”
.
Example 1:
MUL.B 0x800 ; Multiply (0x800)*WREG (Byte mode)
Before
Instruction
After
Instruction
WREG (W0) 9823 WREG (W0) 9823
W2 FFFF W2 13B0
W3 FFFF W3 FFFF
Data 0800 2690 Data 0800 2690
SR 0000 SR 0000

e-Highlighter

Click to send permalink to address bar, or right-click to copy permalink.

Un-highlight all Un-highlight selectionu Highlight selectionh