Translator for translating source code for selective unrolling of loops in the source code

• US 5,121,498 A
• Filed: 05/11/1988
• Issued: 06/09/1992
• Est. Priority Date: 05/11/1988
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Ciccia, Nicodemo A., Gilbert, Ira H.
• Primary Examiner(s): Heckler, Thomas M.
• Application Number:
  US07/193,248
• Time in Patent Office: 1,490 Days
• Field of Search: 364/200, 364/900, 364/300
• US Class Current: 717/149
• CPC Class Codes: G06F 8/452 Loops

Abstract

A translator translates user source code into user object code such as machine code. The translator responds differently to two unique types of loops in the source code. In particular, the translator responds to a first type of loop in the source code by generating an equivalent set of object code instructions that unroll iterations of the loop. In contrast, the translator responds to a second type of loop retaining the loop in the object code. As such, the loop is not unrolled, but rather remains intact.

Claims

1. A data processing system including a processor programmed to act as a translator for translating source code instructions to object code instructions that are executed by the data processing system, the programmed processor comprising:

means for translating a first type of source code instructions that constitute a loop into an equivalent set of unrolled object code instructions for execution by the data processing system; and

means for translating a second type of source code instructions that constitute a loop into object code so as to retain the loop designated by the second type of instructions.

2. A data processing system as recited in claim 1 wherein the data processing system is a single instruction multiple data stream (SIMD) system.

3. A data processing system as recited in claim 1, further comprising an array of computational elements for processing object code in parallel and an array master for generating code processed by the computational elements, the computational elements receiving the object code instructions translated from the first type of source code directly for processing and the array master processing the object code translated from the second type of source code to generate unrolled code processed by the computational elements.

4. In a data processing system, a machine implemented method of translating user source code into executable object code and of executing the object code, comprising the steps of:

retrieving source code from memory;

translating the source code to object code, including;

a) translating a first type of source code instructions that constitute a loop into unrolled object code instructions executable by the data processing system; and

b) translating a second type of source code instructions that constitute a loop into object code instructions executable by the data processing system so as to retain the loop constituted by the second type of source code instructions;

storing the object code instructions in memory; and

executing the object code such that the object code translated from the first type of source code instructions is executed as straight line code and the object code translated from the second type of source code instructions is executed as an indexed loop.

5. A method as recited in claim 4, further comprising providing a plurality of computational elements which process object code instructions in parallel and an array master for processing object code instructions to generate object code instructions processed by the computational elements, the computational elements processing the unrolled object code instructions translated from the first type of source code directly and the array master processing the object code instructions translated from the second type of source code instructions to unroll the loop and generate instructions for the computational elements.