Exponential calculation device and decoding device
First Claim
Patent Images
1. An exponential calculation device for calculating x{circumflex over ( )}(a/b) (where a and b are each an integer constant) for a given input value of x, comprising:
- an input control section for outputting a value of x′
, wherein x′
=x when x≦
A (where A is a threshold value within a variable range of x) and x′
=x/2{circumflex over ( )}b when x>
A;
a core section for outputting a value of z′
=x′
{circumflex over ( )}(a/b); and
an output control section for outputting a value of z, wherein z=z′
when x≦
A and z=z′
*2{circumflex over ( )}a when x>
A.
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Accused Products
Abstract
A device of the present invention is an exponential calculation device for calculating x{circumflex over ( )}(a/b) (where a and b are each an integer constant) for a given input value of x. The device includes: an input control section for outputting a value of x′, wherein x′=x when x≦A (where A is a threshold value within a variable range of x) and x′=x/2{circumflex over ( )}b when x>A; a core section for outputting a value of z′=x′{circumflex over ( )}(a/b); and an output control section for outputting a value of z, wherein z=z′ when x≦A and z=z′*2{circumflex over ( )}a when x>A.
18 Citations
16 Claims
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1. An exponential calculation device for calculating x{circumflex over ( )}(a/b) (where a and b are each an integer constant) for a given input value of x, comprising:
-
an input control section for outputting a value of x′
, wherein x′
=x when x≦
A (where A is a threshold value within a variable range of x) and x′
=x/2{circumflex over ( )}b when x>
A;
a core section for outputting a value of z′
=x′
{circumflex over ( )}(a/b); and
an output control section for outputting a value of z, wherein z=z′
when x≦
A and z=z′
*2{circumflex over ( )}a when x>
A.- View Dependent Claims (2, 3, 4)
-
-
5. An exponential calculation device for calculating x{circumflex over ( )}(a/b) (where a and b are each an integer constant) for a given input value of x, comprising:
-
an input control section for outputting a value of x′
,wherein x′
=x when x≦
A (where A is a threshold value within a variable range of x) and x′
=x/2{circumflex over ( )}(b*n) when x>
A (where n is an integer which satisfies x/2{circumflex over ( )}(b*n)≦
A);
a core section for outputting a value of z′
=x′
{circumflex over ( )}(a/b); and
an output control section for outputting a value of z, wherein z=z′
when x≦
A and z=z′
*2{circumflex over ( )}(a*n) when x>
A.- View Dependent Claims (6, 7, 8)
-
-
9. An exponential calculation device for calculating x{circumflex over ( )}(a/b) (where a and b are each an integer constant) for a given input value of x, comprising:
-
an input control section for outputting a value of x′
, wherein x′
=x when x≦
A (where A is a threshold value within a variable range of x) and x′
=x/2{circumflex over ( )}b when x>
A;
a core section for outputting a value of z′
=x′
{circumflex over ( )}((a%b)/b);
an output control section for outputting a value of z, wherein z=z′
when x≦
A and z=z′
*2{circumflex over ( )}(a%b) when x>
A; and
a multiplication section for outputting z*(x{circumflex over ( )}(int(a/b))). - View Dependent Claims (10)
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-
11. An exponential calculation device for calculating x{circumflex over ( )}(a/b) (where a and b are each an integer constant) for a given input value of x, comprising:
-
a determination section for outputting a parameter j (j is an integer which is not negative) for specifying a value of x;
an input control section for outputting a value of x′
, wherein x′
=x when x≦
A (where A is a threshold value within a variable range of x) and x′
=x/2{circumflex over ( )}j when x>
A;
a core section for outputting a value of z′
=x′
{circumflex over ( )}(a/b); and
an output control section for outputting a value of z, wherein z=z′
when x≦
A and z=z′
*2{circumflex over ( )}(j*a/b) when x>
A.- View Dependent Claims (12, 13)
the output control section includes a memory section for storing values of 2{circumflex over ( )}(j*a/b) using j as an address; and
the value of z is calculated by reading out a corresponding value of 2{circumflex over ( )}(j*a/b) from the memory section when x>
A.
-
-
13. An exponential calculation device according to claim 11, wherein:
-
A=2{circumflex over ( )}B (B is an integer constant); and
the determination section determines the value of j such that 2{circumflex over ( )}(B+(j−
1))≦
x<
2{circumflex over ( )}(B+j) when x>
2{circumflex over ( )}b and such that j=0 when x≦
2{circumflex over ( )}b.
-
-
14. An exponential calculation device for calculating x{circumflex over ( )}(a/b) (where a and b are each an integer constant) for a given input value of x, comprising:
-
a determination section for outputting a value of k which denotes a number of digits of x represented in a binary form;
an input control section for outputting a value of x′
, wherein the value of x′
is obtained by shifting x up by (B−
k) bits when the value of (B−
k) is positive and by shifting x down by (k−
B) bits when the value of (B−
k) is negative;
a core section for outputting a value of z′
=x′
{circumflex over ( )}(a/b); and
an output control section for outputting a value of z=z′
*(2{circumflex over ( )}((k−
B)*a/b)).- View Dependent Claims (15, 16)
the output control section includes a memory section for storing values of 2{circumflex over ( )}((k−
B)*a/b) using k as an address; and
the value of z is calculated by reading out a corresponding value of 2{circumflex over ( )}((k−
B)*a/b) from the memory section.
-
-
16. An exponential calculation device according to claim 14, wherein:
-
the core section includes a memory section for storing values of q{circumflex over ( )}(a/b) (where 2{circumflex over ( )}(B−
1)≦
q<
2{circumflex over ( )}B, and q is an integer) using at least lower (B−
1) bits of q as an address; and
the value of z′
is calculated by reading out a corresponding value of q{circumflex over ( )}(a/b) from the memory section using the at least lower (B−
1) bits of x′
as an address.
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Specification
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- Resources
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Current AssigneeMatsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
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Original AssigneeMatsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
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InventorsSueyoshi, Masahiro, Katayama, Takashi, Nishio, Kosuke, Fujita, Takeshi, Kawamura, Akihisa, Miyasaka, Shuji, Matsumoto, Masaharu, Abe, Kazutaka
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Primary Examiner(s)Mai, Tan V.
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Application NumberUS09/244,155Time in Patent Office986 DaysField of Search708/606, 708/512, 708/517US Class Current708/606CPC Class CodesG06F 7/552 Powers or roots , e.g. Pyth...G10L 19/0212 using orthogonal transforma...
