Vault 7: Projects
This publication series is about specific projects related to the Vault 7 main publication.
© 2005-2011 Microchip Technology Inc. DS70157F-page 295
Section 5. Instruction Descriptions
Instruction
Descriptions
5
MPY
Multiply Wm by Wn to Accumulator
Implemented in: PIC24F PIC24H PIC24E dsPIC30F dsPIC33F dsPIC33E
X X X
Syntax: {label:} MPY Wm * Wn, Acc {,[Wx], Wxd} {,[Wy], Wyd}
{,[Wx] + = kx, Wxd} {,[Wy] + = ky, Wyd}
{,[Wx] – = kx, Wxd} {,[Wy] – = ky, Wyd}
{,[W9 + W12], Wxd} {,[W11 + W12], Wyd}
Operands: Wm * Wn ∈ [W4 * W5, W4 * W6, W4 * W7, W5 * W6, W5 * W7, W6 * W7]
Acc ∈ [A,B]
Wx ∈ [W8, W9]; kx ∈ [-6, -4, -2, 2, 4, 6]; Wxd ∈ [W4 ... W7]
Wy ∈ [W10, W11]; ky ∈ [-6, -4, -2, 2, 4, 6]; Wyd ∈ [W4 ... W7]
AWB ∈ [W13], [W13] + = 2
Operation: (Wm) * (Wn) → Acc(A or B)
([Wx]) → Wxd; (Wx) + kx → Wx
([Wy]) → Wyd; (Wy) + ky → Wy
Status Affected: OA, OB, OAB, SA, SB, SAB
Encoding:
1100 0mmm A0xx yyii iijj
jj11
Description: Multiply the contents of two working registers, optionally prefetch
operands in preparation for another MAC type instruction. The 32-bit result
of the signed multiply is sign-extended to 40 bits and stored to the
specified accumulator.
Operands Wx, Wxd, Wy and Wyd specify optional prefetch operations
which support indirect and register offset addressing, as described in
Section 4.14.1 “MAC Prefetches”.
The ‘m’ bits select the operand registers Wm and Wn for the multiply:
The ‘A’ bit selects the accumulator for the result.
The ‘x’ bits select the prefetch Wxd destination.
The ‘y’ bits select the prefetch Wyd destination.
The ‘i’ bits select the Wx prefetch operation.
The ‘j’ bits select the Wy prefetch operation.
Note 1: The IF bit, CORCON<0>, determines if the multiply is
fractional or an integer.
2: The US<1:0> bits (CORCON<13:12> in dsPIC33E,
CORCON<12> in dsPIC30F/dsPIC33F) determine if the
multiply is unsigned, signed, or mixed-sign. Only dsPIC33E
devices support mixed-sign multiplication.
Words: 1
Cycles: 1
Protego_Release_01_05-Related-OEM-Documentation-PIC24FJ64GA004-Programmers_Reference_Manual.pdf