Out of order instruction load and store comparison

Details Out of order instruction load and store comparison Out of order instruction load and store comparison

1993-01-08

1995-11-14

Geckil, Mehmet

Boots, shoes, and leggings

395375, 364DIG1, 3642433, 36423223, G06F 938

Patent

active

054674735

ABSTRACT:
A processing system allows for out of order instruction execution and includes at least one load/store unit for loading instructions to a register for processing by a fixed point unit, floating point unit, or the like, and store the results to memory. A load queue maintains the addresses and program numbers of the load instructions. During execution the address of the store instruction is compared to the address in the load queue of previously executed load instructions. A program counter compares the program number of the store instruction with the program number of the load instruction in the load queue. If the addresses are different, then no impermissible out of order situation exists between the load and store instructions being compared, because the data is not at the same address. If the address is the same, and the store program number is greater than the load program number, then the instructions have been executed in order (the load correctly preceded the store) and no problem exists. However, if the addresses are the same and the load instruction has been incorrectly reordered to precede the store instruction, then a reordering conflict exists and the load instructions must be re-executed.

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