3
3-72 M32R-FPU Software Manual (Rev.1.01)

MACWLOMACWLO

DSP function instruction

Multiply-accumulate

word and low-order halfword

[Mnemonic]

MACWLO Rsrc1,Rsrc2

[Function]
Multiply and add
accumulator += ( ( signed ) Rsrc1 * ( signed short ) Rsrc2 ) ;
[Description]
MACWLO multiplies the 32 bits of Rsrc1 and the low-order 16 bits of Rsrc2, then adds the
result to the low-order 56 bits in the accumulator.
The LSB of the multiplication result is aligned with the LSB of the accumulator, and the portion
corresponding to bits 8 through 15 of the accumulator is sign-extended before the addition. The
result of the addition is stored in the accumulator. The 32 bits Rsrc1 and the low-order 16 bits of
Rsrc2 are treated as signed values.
The condition bit (C) is unchanged.
[EIT occurrence]
None
[Encoding]
Rsrc1
32 bits
Rsrc2
low-order 16 bits
x
0151631
+
01516313247486378
Result of the multiplication
Value in accumulator before the
execution of the MACWLO instruction
Value in accumulator after the
execution of the MACWLO instruction
Sign extension
Sign extension

src10011 MACWLO Rsrc1,Rsrc2src20111

INSTRUCTIONS
3.2 Instruction description