Circuits, barrel shifters, and methods of manipulating a bit pattern

• US 6,317,763 B1
• Filed: 11/08/1999
• Issued: 11/13/2001
• Est. Priority Date: 12/19/1996
• Status: Expired due to Term

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: VLSI Technology, Inc. (Koninklijke Philips N.V.)
• Inventors: Vatinel, Christopher
• Primary Examiner(s): Ngo, Chuong Dinh
• Application Number:
  US09/435,894
• Time in Patent Office: 736 Days
• Field of Search: 708/209, 377/69, 377/73, 377/75, 377/77
• US Class Current: 708/209
• CPC Class Codes: G06F 5/015 having at least two separately controlled shifting levels, e.g. using shifting matrices G06F5/012 takes precedence
• CPC Class Codes: G06F 7/768 Data position reversal, e.g. bit reversal, byte swapping

Abstract

The present invention provides for a circuit comprising: an input operable to receive a bit pattern; a shifter configured to selectively shift the bit pattern; a data output operable to output the bit pattern; and a sign extension operator coupled with the data output and operable to provide a sign extension signal thereto. The present invention additionally discloses a barrel shifter and a method for manipulating a bit pattern.

Claims

1. A circuit comprising:

an input operable to receive a bit pattern;

a shifter configured to selectively shift the bit pattern;

a plurality of output data lines operable to output the bit pattern from the shifter; and

a sign extension operator operable to provide a sign extension signal directly to selected ones of the output data lines; and

a bit-operator configured to transpose the bit pattern.

2. The circuit according to claim 1 wherein the sign extension operator includes a plurality of drivers.

3. The circuit according to claim 2 wherein the drivers are three-state drivers.

4. The circuit according to claim 1 further comprising a decoder operable to control the sign extension operator responsive to at least one control signal.

5. The circuit according to claim 1 further comprising a decoder operable to control the sign extension operator responsive to at least one control signal.

6. The circuit according to claim 1 wherein the sign extension operator is void of switching circuits.

7. A circuit comprising:

an input operable to receive a bit pattern;

a shifter comprising an array of switching circuits configured to selectively shift the bit pattern;

a sign extension operator configured to input a sign extension signal into the bit pattern without use of the switching circuits of the array;

a data output operable to output the bit pattern; and

a bit-operator configured to transpose the bit pattern.

8. The circuit according to claim 7 wherein the sign extension operator comprises a plurality of drivers.

9. The circuit according to claim 8 further comprising a decoder operable to selectively enable individual ones of the drivers responsive to at least one control signal.

10. The circuit according to claim 7 wherein the switching circuits comprise passgates.

11. The circuit according to claim 7 wherein the sign extension operator is configured to provide the sign extension signal directly to a plurality of output data lines coupled with the shifter.

12. A barrel shifter comprising:

a plurality of input data lines operable to receive a bit pattern;

a plurality of output data lines operable to output the bit pattern;

a shifter configured to selectively shift at least a portion of the bit pattern from the input data lines to selected ones of the output data lines; and

a sign extension operator including a plurality of three-state drivers configured to provide a sign extension signal directly to selected others of the output data lines.

13. The barrel shifter according to claim 12 further comprising a decoder operable to control the sign extension operator responsive to at least one control signal.

14. The barrel shifter according to claim 12 wherein the sign extension operator is void of switching circuits.

15. A method of manipulating a bit pattern, comprising the steps of:

receiving a bit pattern;

providing the bit pattern on a plurality of input data lines;

shifting at least a portion of the bit pattern to selected ones of a plurality of output data lines using a plurality of switching circuits;

providing a sign extension signal to selected others of the output data lines via a sign extension operator without use of the switching circuits;

outputting the bit pattern and the sign extension signal; and

transposing the bit pattern.

16. The method according to claim 15 further comprising the step of receiving a plurality of control signals.

17. The method according to claim 15 wherein the providing the sign extension signal comprises providing the sign extension signal via a sign extension operator comprising a plurality of drivers coupled with the selected others of the output data lines.

18. The method according to claim 15 wherein the providing the sign extension signal comprises directly providing the sign extension signal to the selected others of the output data lines.

19. A method of manipulating a bit pattern, comprising the steps of:

receiving a bit pattern;

providing the bit pattern on a plurality of input data lines;

shifting at least a portion of the bit pattern to selected ones of a plurality of output data lines;

providing a sign extension signal directly to selected others of the output data lines via a sign extension operator;

outputting the bit pattern and the sign extension signal; and

transposing the bit pattern.

20. The method according to claim 19 wherein the providing the sign extension signal comprises providing the sign extension signal via a sign extension operator comprising a plurality of drivers coupled with the selected others of the output data lines.

21. A barrel shifter comprising:

a plurality of input data lines operable to receive a bit pattern;

a plurality of output data lines operable to output the bit pattern;

a shifter configured to selectively shift at least a portion of the bit pattern from the input data lines to selected ones of the output data lines;

a sign extension operator configured to provide a sign extension signal directly to selected others of the output data lines; and

a bit-operator configured to transpose the bit pattern responsive to at least one control signal.

22. The shifter of claim 21 further comprising a decoder operable to control the sign extension operator responsive to at least one control signal.