Renesas M32R-FPU User Manual

3

3-75

M32R-FPU Software Manual (Rev.1.01)

DSP function instruction

Multiply

accumulator = (  ( signed ) ( Rsrc1 << 16 ) * ( signed short )  Rsrc2  );

MULLO multiplies the low-order 16 bits of Rsrc1 and the low-order 16 bits of Rsrc2, and stores

the result in the accumulator.

The LSB of the multiplication result is aligned with bit 47 in the accumulator, and the portion

corresponding to bits 0 through 15 of the accumulator is sign extended.  Bits 48 through 63 of the

accumulator are cleared to 0.  The low-order 16 bits of Rsrc1 and Rsrc2 are treated as signed

values.

The condition bit (C) is unchanged.

None

Rsrc1

Rsrc2

x

0

15 16

31

low-order 16 bits

0

0

15 16

31 32

47 48

63

low-order 16 bits

Value in accumulator after the
execution of the MULLO instruction

Sign extension

INSTRUCTIONS

3.2 Instruction description