Freescale Semiconductor SC140 Dmacss d2,d3,d5, Dn16 + Dc.H * Dd.H → Dn, Dc signed, Dd signed

Models: SC140

1 760
Download 760 pages 48.94 Kb
Page 467
Image 467

 

 

 

 

DMACSS

 

 

 

 

DMACSS

Multiply Signed By Signed and

DMACSS

 

Accumulate With Right Shifted Data Register (DALU)

Operation

 

Assembler Syntax

 

[Dn>>16] + Dc.H * Dd.H → Dn

DMACSS Dc,Dd,Dn

 

(Dc signed, Dd signed)

 

 

 

Description

DMACSS Dc,Dd,Dn

Shifts Dn 16 bits to the right with bit 39 sign-extended into bits [39:24]. Adds the result to the product of signed fractions in Dc.H and Dd.H. Places the result into Dn.

Dc and Dd are a data register pair. The operands are in the HP of each register.

This instruction is optimized for multi-precision-multiplication support.

Status and Conditions that Affect Instruction

None.

Status and Conditions Changed by Instruction

Register Address

Bit Name

Description

Ln

L

Clears the Ln bit in the destination register.

Example

dmacss d2,d3,d5

Register/Memory Address

D2

D3

L5:D5

EMR

Before

$00 0002 0000

$00 0003 0000

$0:$00 0050 0000

After

$0:$00 0000 005C

$0000 0000

$00 0002 0000

2-14

 

 

x $00 0003

0000

2-14

+

2-15

$00 0000

000C

2-28

+

2-29

+$00 0000 0050 $00 0000 005C

SC140 DSP Core Reference Manual

A-153

Page 467
Image 467
Freescale Semiconductor SC140 Dmacss d2,d3,d5, Dn16 + Dc.H * Dd.H → Dn, Dc signed, Dd signed, Dmacss Dc,Dd,Dn