Method and apparatus for loading or storing multiple registers in a data processing system
A method for operating a data processing system includes providing an application binary interface (ABI) which determines a set of non-contiguous volatile registers and a set of non-volatile registers. The set of non-contiguous volatile registers includes a plurality of general purpose registers (GPRs) and a plurality of special purpose registers (SPRs). The method includes providing less than three instructions which collectively load or store all of the set of non-contiguous volatile registers determined by the ABI. A system includes a set of volatile registers including a plurality of volatile GPRs, a plurality of volatile supervisor SPRs, and a plurality of volatile user SPRs, and execution circuitry for executing a first instruction that loads or stores the plurality of volatile supervisor SPRs, for executing a second instruction that loads or stores the plurality of volatile GPRs, and for executing a third instruction that loads or stores the plurality of volatile user SPRs.
1. A method for operating a data processing system, the method comprising:
providing a set of non-contiguous volatile registers of the data processing system and a set of non-volatile registers of the data processing system, wherein each set is determined by an application binary interface, and wherein the set of non-contiguous volatile registers comprises a plurality of general purpose registers and a plurality of special purpose registers; and
providing less than three single instructions which, when executed by execution circuitry, collectively load or store all of the set of non-contiguous volatile registers determined by the application binary interface, wherein the set of non-contiguous volatile registers includes every volatile register defined by the application binary interface, wherein the collectively loading or storing of all of the set of non-contiguous volatile registers is performed in less than 3 single units of instruction execution.
2. A method as in claim 1 , wherein the load is from a stack and the store is to the stack.
3. A method as in claim 1 , wherein the less than three instructions comprises a first instruction for loading or storing at least one of the plurality of special purpose registers.
4. A method as in claim 3 , wherein the first instruction is executable when the data processing system is in either a supervisor mode or a user mode.
5. A method as in claim 1 , wherein the less than three instructions comprises a first instruction for loading or storing all non-contiguous volatile general purpose registers within the set of non-contiguous volatile registers.
6. A method as in claim 3 , wherein the first instruction comprises a field to optionally update a stack pointer.
7. A method for operating a data processing system, the method comprising:
providing a plurality of registers r 0 , r 1 , . . . rN, wherein the plurality of registers are contiguous in a programmer's model corresponding to the data processing system;
providing a single instruction; and
executing the single instruction by execution circuitry, the executing the single instruction results in loading or storing a subset of the plurality of registers, wherein the loading or storing of the subset of the plurality of registers is performed in a single unit of instruction execution,
wherein the subset of the plurality of registers is non-contiguous and includes every volatile general purpose register defined by an application binary interface;
and wherein which registers of the plurality of registers are part of the subset of the plurality of registers is specified in a maskless process.
8. A method as in claim 7 , wherein the single instruction comprises 32 bits and the plurality of registers comprises at least 32 registers.
9. A method as in claim 7 , wherein the subset of the plurality of registers comprises general purpose registers r 0 and r 3 -r 12 .
10. A method as in claim 7 , wherein the single instruction is interruptible.
11. A method as in claim 7 , wherein the loading is from a stack and the storing is to the stack.
12. A method as in claim 7 , wherein the single instruction comprises a field to optionally update a stack pointer.
13. A data processing system implemented at least partially in hardware, comprising:
a set of volatile registers comprising a plurality of volatile general purpose registers, a plurality of volatile supervisor special purpose registers, and a plurality of volatile user special purpose registers; and
execution circuitry for executing a first single instruction that loads or stores the plurality of supervisor special purpose registers, for executing a second single instruction that loads or stores the plurality of volatile general purpose registers, and for executing a third single instruction that loads or stores the plurality of volatile user special purpose registers, wherein:
the loading or storing the plurality of supervisor special purpose registers is performed in a single unit of instruction execution of the first single instruction,
the loading or storing the plurality of volatile general purpose registers is performed in a single unit of instruction execution of the second single instruction, and
the loading or storing of the plurality of volatile user special purpose registers is performed in a single unit of instruction execution of the third single instruction.
14. A method for operating a data processing system, the method comprising:
providing a set of volatile registers and a set of non-volatile registers, wherein each set is determined by an application binary interface, and wherein the set of volatile registers comprises a plurality of non-contiguous volatile general purpose registers; and
providing a first single instruction to execution circuitry which, when executed, stores the plurality of non-contiguous volatile general purpose registers, wherein the plurality of non-contiguous volatile general purpose registers includes every volatile general purpose register defined by the application binary interface, wherein the storing of the plurality of non-contiguous volatile general purpose registers is performed in a single unit of instruction execution.