Substituting portion of template instruction parameter with selected virtual instruction parameter

• US 8,447,958 B2
• Filed: 03/06/2009
• Issued: 05/21/2013
• Est. Priority Date: 02/21/2001
• Status: Expired due to Term

• Current Assignee: ARM Finance Overseas Limited (SoftBank Group Corp.)
• Original Assignee: Bridge Crossing LLC (Allied Security Trust)
• Inventors: Kissell, Kevin D.
• Primary Examiner(s): KIM, KENNETH S
• Application Number:
  US12/399,330
• Publication Number:
  US 20090198986A1
• Time in Patent Office: 1,537 Days
• Field of Search: None
• US Class Current: 712/226
• CPC Class Codes: G06F 9/30167 of immediate specifier, e.g. constants
• CPC Class Codes: G06F 9/3017 Runtime instruction translation, e.g. macros
• CPC Class Codes: G06F 9/30181 Instruction operation extension or modification

Abstract

A configurable instruction set architecture is provided whereby a single virtual instruction may be used to generate a sequence of instructions. Dynamic parameter substitution may be used to substitute parameters specified by a virtual instruction into instructions within a virtual instruction sequence.

Claims

1. A pipelined microprocessor, comprising:

instruction decode logic;

a program counter configured to indicate a current location in a first instruction sequence;

instruction fetch. Logic configured to fetch a first instruction from the current location in the first instruction sequence; and

a parameter selector

configured to, if the fetched first instruction from the first instruction sequence is a virtual instruction having one or more parameters, select a parameter from the one or more parameters of the first instruction based on control data, and

wherein the instruction fetch logic is further configured to;

maintain the first program counter at the address of the virtual instruction,

select a second instruction sequence based on the virtual instruction,

modify the selected parameter, wherein the modification of the selected parameter comprises sign-extending the selected parameter,

substitute the modified parameter from the first instruction into a second instruction, the second instruction being from the second instruction sequence,

pass each instruction of the second instruction sequence to the instruction decode logic, and

after the second instruction sequence has been executed or an exception occurs, advance the program counter and resume the first instruction sequence.

2. The pipelined microprocessor of claim 1, wherein the instruction fetch logic is configured to substitute the modified parameter into the second instruction based on an instruction template.

3. The pipelined microprocessor of claim 1, wherein the second instruction sequence includes a conditional move instruction, and wherein the instruction fetch logic substitutes the modified parameter from the first instruction into the conditional move instruction.

4. The pipelined microprocessor of claim 1, wherein the second instruction sequence includes an instruction for branching, and wherein the parameter selector substitutes the modified parameter from the first instruction into the instruction for branching.

5. The pipelined microprocessor of claim 1, wherein the second instruction sequence terminates with a control transfer instruction.

6. The pipelined microprocessor of claim 1, wherein modification of the selected parameter further comprises translating a length of the selected parameter from one bit length to another bit-length.

7. The pipelined microprocessor of claim 1, wherein the selected parameter and the modified parameter have different bit-widths.

8. The pipelined microprocessor of claim 1, wherein modification of the selected parameter is based on an instruction template.

9. A method for implementing virtual instructions in a processor, the method comprising:

fetching a virtual instruction from a first sequence of instructions, wherein the virtual instruction has one or more parameters;

determining a second sequence of instructions to be executed based on the virtual instruction;

selecting an instruction from the second sequence of instructions;

selecting a parameter from the one or more parameters of the virtual instruction based on control data;

modifying the selected parameter, wherein the modification of the selected parameter comprises sign-extending the selected parameter;

substituting a parameter of the selected instruction with the modified parameter from the virtual instruction;

passing each of the second sequence of instructions to the instruction decode logic; and

resuming the fetching of instructions from the first sequence of instructions.

10. A pipelined microprocessor, comprising:

instruction decode logic;

a program counter configured to indicate a current location in a first instruction sequence;

instruction fetch logic configured to fetch a first instruction from the current location in the first instruction sequence; and

a parameter selector

configured to, if the fetched first instructions a virtual instruction having one or more parameters, select a first parameter from the one or more parameters of the first instruction based on control data, and

wherein the instruction fetch logic is further configured to;

maintain the first program counter at the address of the virtual instruction,

select a second instruction sequence based on the virtual instruction,

select a second parameter from a second instruction in the second instruction sequence;

modify the second parameter, wherein the modification replaces a portion of the second parameter with the first parameter,

pass each instruction of the second instruction sequence to the instruction decode logic, and

after the second instruction sequence has been executed or an exception occurs, advance the program counter and resume the first instruction sequence.

11. A method for implementing virtual instructions in a processor, the method comprising:

fetching a virtual instruction from a first sequence of instructions, wherein the virtual instruction has one or more parameters;

determining a second sequence of instructions to be executed based on the virtual instruction;

selecting an instruction from the second sequence of instructions;

selecting a first and second parameter from the one or more parameters of the virtual instruction based on control data;

selecting a third parameter from the second instruction;

modifying the third parameter based on the first and second parameters, wherein the modification of the third parameter comprises at least one of;

concatenating the first parameter with the second parameter, and

replacing the third parameter with the concatenated first and second parameters,

passing each of the second sequence of instructions to the instruction decode logic; and

resuming the fetching of instructions from the first sequence of instructions.

12. The method of claim 11, wherein the first and second selected parameters have different bit-widths.

13. The method of claim 11, wherein the modification of the third parameter is based on an instruction template.

14. The method of claim 11, wherein the second sequence of instructions includes a conditional move instruction, and wherein modifying the third parameter comprises modifying a parameter of the conditional move instruction based on the first parameter.

15. The method of claim 11, wherein the second sequence of instructions includes a branch instruction, and wherein modifying the third parameter comprises modifying a parameter of the branch instruction based on the first parameter.

16. The method of claim 11, wherein the second sequence of instructions terminates with a control transfer instruction.