Freescale Semiconductor SC140 specifications Signed Integer Double-Precision Multiplication

Models: SC140

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DALU

Figure 2-10 illustrates the use of these instructions in the case of a signed integer double-precision multiplication of 32-bit by 32-bit signed operands. In this example, only a 32-bit result is generated. The most significant 32 bits are shifted out.The “Unsigned x Unsigned” operation is used to multiply or multiply-accumulate the unsigned low portion of one double-precision number with the unsigned low portion of the other double-precision number. The “Signed x Unsigned” and “Unsigned x Signed” operations are used to multiply or multiply-accumulate the signed high portion of one double-precision number with the unsigned low portion of the other double-precision number. This example generates only a 32-bit integer.

impyuu

D0,D1,D2

impysu

D0,D1,D3

imacus

D0,D1,D3

aslw

D3

add

D2,D3

 

 

 

 

 

 

 

32 bits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D0.h

 

 

 

D0.l

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D1.h

 

 

 

D1.l

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

=

 

 

 

 

 

 

 

 

 

Unsigned Unsigned

 

 

 

 

 

 

 

D1.l D0.l

 

 

Signed

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Unsigned

 

 

 

 

 

 

 

 

D0.h D1.l

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Unsigned Signed

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D1.h D0.l

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D3.l

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D3.h

 

 

 

D3.l

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

32 bits

 

 

 

 

 

 

 

 

 

 

AA0551

Figure 2-10. Signed Integer Double-Precision Multiplication

SC140 DSP Core Reference Manual

2-29

Page 61
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Freescale Semiconductor SC140 specifications Signed Integer Double-Precision Multiplication