Permission control for contingent memory access program instruction

Apparatus for processing data comprising:

• memory access circuitry responsive to a memory access program instruction of a program to perform one or more memory accesses within a memory address space, wherein
• when said memory access program instruction is a contingent memory access program instruction, said one or more memory accesses include at least one contingent memory access and program flow to a next program instruction to be executed following said contingent memory access program instructions is independent of whether said at least one contingent memory access is permitted;
• and
• when said memory access program instruction is a non-contingent memory access program instruction, said one or more memory accesses are one or more non-contingent memory accesses and program flow to a next program instruction to be executed following said non-contingent memory access program instructions is dependent upon whether said one or more non-contingent memory accesses is permitted;
• and
• memory permission circuitry to control whether said memory access circuitry is permitted to perform said memory access, wherein
• in respect of said one or more contingent memory accesses, said memory permission circuitry is responsive to a contingent-access permission checking disable flag having a first value to disable said control by said memory permission circuitry and to said contingent-access permission checking disable flag having a second value to enable said control by said memory permission circuitry;
• and
• in respect of said one or more non-contingent memory accesses, said control by said memory permission circuitry is independent of said contingent-access permission checking disable flag.