Re: A89: Starting out assembly, need help
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Re: A89: Starting out assembly, need help
>
>1 2 3 4 5 6 7 8 9 10
>IF ID EX MA WB
> IF ID EX MA WB
> IF ID EX MA WB
> IF ID EX MA WB
> IF ID EX MA WB
> IF ID EX MA WB
>
>IF -- Instruction fetch: The processor reads the pc and finds the next
>instruction.
>ID -- Instruction decode: Look at the instruction and figure out what it
is
>EX -- Execute: If it is an add, do the add. If it is a load or store do
>the effective memory calculation
>MA -- Memory access: If it is a load or a store, access memory. Otherwise
>do nothing
>WB -- Write the calculated value back to the destination register
>
This pipeline model does not apply to any CPU of the m68k series. Probably
it
doesnt apply to any cpu at all. Usually the Memory Read takes please before
instruction execution. (would make no sense otherwhise)
memory accesses are usually also split up in reads and writes. Reads take
place
before the ex-stage and write take place in the wb stage.
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