US 11,704,127 B2
Marking current context data to control a context-data-dependent processing operation to save current or default context data to a data location
Thomas Christopher Grocutt, Cambridge (GB); François Christopher Jacques Botman, Cambridge (GB); and Bradley John Smith, Cambridge (GB)
Assigned to Arm Limited, Cambridge (GB)
Appl. No. 16/628,418
Filed by ARM LIMITED, Cambridge (GB)
PCT Filed Jun. 19, 2018, PCT No. PCT/GB2018/051701
§ 371(c)(1), (2) Date Jan. 3, 2020,
PCT Pub. No. WO2019/008323, PCT Pub. Date Jan. 10, 2019.
Claims priority of application No. 1710790 (GB), filed on Jul. 5, 2017.
Prior Publication US 2020/0167160 A1, May 28, 2020
Int. Cl. G06F 9/312 (2018.01); G06F 9/46 (2006.01); G06F 9/30 (2018.01)
CPC G06F 9/30043 (2013.01) [G06F 9/3013 (2013.01); G06F 9/30189 (2013.01); G06F 9/461 (2013.01)] 17 Claims
OG exemplary drawing
 
1. Apparatus for processing data comprising:
processing circuitry to perform processing operations under control of program instructions;
at least one floating point context data register configured to store context data; and
decoder circuitry to decode said program instructions to generate control signals to control said processing circuitry to perform said processing operations; wherein
said decoder circuitry is responsive to a context-data-dependent program instruction and current context data stored in said at least one floating point context data register to generate said control signals to control said processing circuitry to perform a context-data-dependent processing operation specified by said context-data-dependent program instruction and said current context data,
wherein said decoder circuitry is responsive to a context save instruction:
in response to said current context data being marked as having been used to control a context-data-dependent processing operation, to control said processing circuitry to save said current context data to a data location to be restored to the at least one floating point context data register in response to a subsequent context restore instruction;
in response to said current context data being marked as having been unused to control a context-data-dependent processing operation, to control said processing circuitry to save default context data to said data location to be restored to the at least one floating point context data register in response to the subsequent context restore instruction, and
wherein said default context data is default floating point configuration data.