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dji
Mar 8, 2012, 9:22:15 PM3/8/12
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There are 9 cycles in the forms provided (just like the example in class), but the instructions in this question should take a total of 11 cycles (including the last cycle only showing FLR entries). Is that the case, or am I missing something?
Andrew Morton
Mar 9, 2012, 1:05:59 PM3/9/12
to dji
If you label the instructions w, x, y and z, then w preceeds x and y, and
y proceeds z. The execution of x and y can be overlapped because the
FMUL/FDIV unit is pipelined. So x can start in cycle 3 and y can start in
cycle 4. So it should all fit in 9 cycles.
Andrew
y proceeds z. The execution of x and y can be overlapped because the
FMUL/FDIV unit is pipelined. So x can start in cycle 3 and y can start in
cycle 4. So it should all fit in 9 cycles.
Andrew
dji
Mar 10, 2012, 3:54:19 PM3/10/12
to dji
I forgot they are pipelined. For FMUL/DIV ex unit,we can fill at most 3 instruction names in it for 1 cycle since it's 3-cycle pipeline, is that right?
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