Conditional execution of coprocessor instruction based on main processor arithmetic flags
View Patent ↗A processor-based system may include a main processor and a coprocessor. The coprocessor handles instructions that include opcodes specifying a data processing operation to be performed by the coprocessor and a coprocessor identification field for identifying a target coprocessor for coprocessor instructions. Two bits indicate one of four data sizes including a byte (8 bits), a half word (16 bits), a word (32 bits), and a double word (64 bits). Two other bits indicate a saturation type.
1. A method comprising:
performing data processing using a main processor in response to a stream of data processing instructions, said data processing instructions including at least one coprocessor instruction;
providing two source registers and a destination register for said at least one coprocessor instruction;
providing a coprocessor instruction that includes an opcode specifying a data processing operation to be performed by the coprocessor and a coprocessor identification field for identifying a target coprocessor for the coprocessor instruction;
conditionally executing the coprocessor instruction dependent on a state of a main processor arithmetic flag; and
providing two bits that indicate data sizes including a byte or eight bits, a half word or sixteen bits, a data word or thirty-two bits, and a double word or sixty-four bits.
2. The method of claim 1 including providing two bits that indicate a saturation type.
3. The method of claim 1 including specifying the data processing operation to be addition.
4. The method of claim 1 including specifying the data processing operation to be subtraction.
5. The method of claim 1 including providing three different saturation types including signed saturation, no saturation, and unsigned saturation.
6. The method of claim 1 including assigning the bits zero through thirty-one, using bits seven through five to indicate the operation type, assigning the bits eleven through eight to indicate the coprocessor number, assigning the bits 23 and 22 to indicate the operand size, and assigning the bits 21 and 20 to set the saturation type.
7. The method of claim 1 including assigning the bits 27 to 24 to be 1110.
8. An article comprising a medium storing instructions that, if executed, enable a processor-based system executed, enable a processor-based system including a main processor and a coprocessor to perform the steps of:
performing data processing using a main processor in response to a stream of data processing instructions, said data processing instructions including at least one coprocessor instruction;
providing two source registers and one destination register for said at least one coprocessor instruction;
providing a coprocessor instruction that includes an opcode specifying a data processing operation to be performed by the coprocessor and a coprocessor identification field for identifying a target coprocessor for the coprocessor instruction;
providing two bits that indicate one of four data sizes including a byte or eight bits, a half word or sixteen bits, a data word or thirty-two bits, and a double word or sixty-four bits; and
conditionally executing the coprocessor instruction dependent on a state of a main processor arithmetic flag.
9. The article of claim 8 further storing instructions that, if executed, enable a processor-based system to perform the step of providing two bits that indicate a saturation type.
10. The article of claim 8 further storing instructions that enable a processor-based system, if executed, to perform the step of specifying the data processing operation to be addition.
11. The article of claim 8 further storing instructions that enable a processor-based system, if executed, to perform the step of specifying the data processing operation to be subtraction.
12. The article of claim 8 further storing instructions that, if executed, enable the processor-based system to perform the step of providing three different saturation types including signed saturation, no saturation, and unsigned saturation.
13. The article of claim 8 further storing instructions that, if executed, enable the processor-based system to perform the steps of assigning the bits zero through thirty-one, using bits seven through five to indicate the operation type, assigning the bits eleven through eight to indicate the coprocessor number, assigning the bits twenty-three and twenty-two to indicate the operand size, and assigning the bits twenty-one and twenty to set the saturation type.
14. A processor comprising:
a main processor including an arithmetic flag; and
a coprocessor coupled to said main processor, said coprocessor use opcodes specifying a data processing operation to be performed by the coprocessor and a coprocessor identification field for identifying a target coprocessor for the coprocessor instructions, said coprocessor to recognize instruction sequence bits that indicate one of four data types including a byte or eight bits, a half word or sixteen bits, a data word or thirty-two bits, and a double word or sixty-four bits, said coprocessor to allocate two source registers and a destination register for each coprocessor instruction and said coprocessor to conditionally execute an instruction depending on a state of a main processor arithmetic flag.
15. The processor of claim 14 wherein said coprocessor is a single instruction multiple data coprocessor.
16. The processor of claim 14 wherein said coprocessor handles signed saturation, no saturation, and unsigned saturation.
17. The processor of claim 14 wherein said coprocessor recognizes two bits of an instruction sequence that indicate one of four data sizes and two bits that indicate a saturation type.
18. The processor of claim 14 wherein said coprocessor uses instructions having bits zero through thirty-one, and wherein bits seven through five indicate the operation type, bits eleven through eight indicate the coprocessor number, bits twenty-three and twenty-two indicate the operand size, and bits twenty-one and twenty set the saturation type.
19. A system comprising:
a main processor;
a coprocessor coupled to said main processor, said coprocessor to use opcodes specifying a data processing operation to be performed by the coprocessor and a coprocessor identification field for identifying a target coprocessor for the coprocessor instructions, said coprocessor recognizing instruction sequence bits that indicate one of four data types including a byte or eight bits, a half word or sixteen bits, a data word or thirty-two bits, and a double word or sixty-four bits, said coprocessor to allocate two source registers and one destination register for a coprocessor instruction and said coprocessor to conditionally execute an instruction depending on the state of a main processor arithmetic flag; and
a wireless interface coupled to said main processor.
20. The system of claim 19 wherein said coprocessor instructions have bits twenty-seven to twenty-four that are 1110.
21. The system of claim 19 wherein said coprocessor has three different types of saturation including signed saturation, no saturation, and unsigned saturation.
22. The system of claim 19 wherein said coprocessor uses the instructions zero through thirty-one, with bits seven through five indicating the operation type, bits eleven through eight indicating the coprocessor number, the bits twenty-three and twenty-two indicating the operand size and the bits twenty-one to twenty setting the saturation type.