Imacus, Integer multiply accumulate, Operation assembler syntax – Freescale Semiconductor StarCore SC140 User Manual
Page 499
IMACUS
SC140 DSP Core Reference Manual
A-185
IMACUS
Integer Multiply Accumulate
IMACUS
Unsigned By Signed (DALU)
Description
Status and Conditions that Affect Instruction
None.
Status and Conditions Changed by Instruction
Example
imacus d3,d4,d0
Operation
Assembler Syntax
Dn + (Da.L * Db.H)
→ Dn
IMACUS Da,Db,Dn
IMACUS Da,Db,Dn
Performs a signed integer multiplication of the unsigned 16-bit LP of one source data register (Da) with the
signed 16-bit HP of another source data register (Db). It then adds the sign-extended 32-bit product to a
destination data register (Dn). This instruction is optimized for multi-precision-multiplication support.
Register Address
Bit Name
Description
Ln
L
Clears the Ln bit in the destination register.
EMR[2]
DOVF
Set if the result cannot be represented in 40 bits.
Register/Memory Address
Before
After
D3
$00 7CE8 0002
D4
$FF FFC0 F0D0
L0:D0
$0:$00 0000 0000
$0:$FF FFFF FF80
EMR
$0000 0000