A coprocessor performs operations on behalf of processes executing in processors coupled thereto, and accesses data operands in memory using real addresses. A process executing in a processor generates an effective address for a coprocessor request, invokes the processor's address translation mechanisms to generate a corresponding real address, and passes this real address is the coprocessor. Preferably, the real address references a block of additional real addresses, each for a respective data operand. The coprocessor uses the real address to access the data operands to perform the operation. An address context detection mechanism detects the occurrence of certain events which could alter the context of real addresses used by the coprocessor or the real addresses themselves.