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16-bit MCU and DSC Programmer’s Reference Manual
DS70157F-page 308 © 2005-2011 Microchip Technology Inc.
MUL.SU
Integer 16x16-bit Signed-Unsigned Short Literal Multiply
Implemented in: PIC24F PIC24H PIC24E dsPIC30F dsPIC33F dsPIC33E
X X X X X X
Syntax: {label:} MUL.SU Wb, #lit5, Wnd
Operands: Wb ∈ [W0 ... W15]
lit5 ∈ [0 ... 31]
Wnd ∈ [W0, W2, W4 ... W12]
Operation: signed (Wb) * unsigned lit5 → Wnd:Wnd + 1
Status Affected: None
Encoding:
1011 1001 0www wddd d11k kkkk
Description: Multiply the contents of Wb with the 5-bit literal, and store the 32-bit
result in two successive working registers. The least significant word of
the result is stored in Wnd (which must be an even numbered working
register), and the most significant word of the result is stored in Wnd + 1.
The Wb operand and the result Wnd are interpreted as a two’s
complement signed integer. The literal is interpreted as an unsigned
integer. Register direct addressing must be used for Wb and Wnd.
The ‘w’ bits select the address of the base register.
The ‘d’ bits select the address of the lower destination register.
The ‘k’ bits define a 5-bit unsigned integer literal.
Note 1: This instruction operates in Word mode only.
2: Since the product of the multiplication is 32 bits, Wnd must be
an even working register. See Figure 4-3 for information on
how double words are aligned in memory.
3: Wnd may not be W14, since W15<0> is fixed to zero.
4: The IF bit and the US<1:0> bits in the CORCON register have
no effect on this operation.
Words: 1
Cycles: 1
Example 1:
MUL.SU W0, #0x1F, W2 ; Multiply W0 by literal 0x1F
; Store the result to W2:W3
Before
Instruction
After
Instruction
W0 C000 W0 C000
W2 1234 W2 4000
W3 C9BA W3 FFF8
SR 0000 SR 0000
Protego_Release_01_05-Related-OEM-Documentation-PIC24FJ64GA004-Programmers_Reference_Manual.pdf