Stmicroelectronics S.a.

Bruno Bernard

Nicolas Grossier

Ahmed Dabbagh

Andrew Cofler

Isabelle Sename

Pierre-Yves Taloud

A computer memory access controller receives load and store requests from a plurality of parallel execution pipelines and forms queues of store and load addresses. A comparator compares load addresses with store addresses in a store address queue and selects a store before load if an address match is found, but selects a load before a store if no address match is found.

Memory access in a computer system having parallel execution pipelines

A computer system includes instruction fetch circuitry for dispatching fetched instructions to a pipelined execution unit, data memory access circuitry and emulator circuitry for use in debug operations, said emulator circuitry including error indicating circuitry to indicate an error in a data memory access operation, snoop circuitry for snooping memory access operation in said data memory access circuitry, synchronising means for synchronising snooped data memory access addresses with respective program counts for the instructions associated with said access addresses, memory mapped storage circuitry responsive to a data memory access error to indicate the data memory address associated with the error, whereby the emulator circuitry may use the data memory address in a subsequent operation to obtain from the synchronising means the specific program count associated with the memory access operation in which the error occurred.

Memory access debug facility

A computer system with parallel execution pipelines and a memory access controller has store address queues holding addresses for store operations, store data queues holding a plurality of data for storing in the memory and load address storage holding addresses for load operations, said access controller including comparator circuitry to compare load addresses received by the controller with addresses in the store address queue and locate any addresses which are the same, each of said addresses including a first set of bits representing a word address together with a second set of byte enable bits and said comparator having circuitry to compare the byte enable bits of two addresses as well as said first set of bits.

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Echirolles, France

Bruno Bernard