Return to README CVS log

Up to [local] / OpenXM_contrib / gmp / mpn / powerpc64

Annotation of OpenXM_contrib/gmp/mpn/powerpc64/README, Revision 1.1

1.1     ! maekawa     1: PPC630 (aka Power3) pipeline information:
        !             2:
        !             3: Decoding is 4-way and issue is 8-way with some out-of-order capability.
        !             4: LS1  - ld/st unit 1
        !             5: LS2  - ld/st unit 2
        !             6: FXU1 - integer unit 1, handles any simple integer instructions
        !             7: FXU2 - integer unit 2, handles any simple integer instructions
        !             8: FXU3 - integer unit 3, handles integer multiply and divide
        !             9: FPU1 - floating-point unit 1
        !            10: FPU2 - floating-point unit 2
        !            11:
        !            12: Memory:                  Any two memory operations can issue, but memory subsystem
        !            13:                  can sustain just one store per cycle.
        !            14: Simple integer:          2 operations (such as add, rl*)
        !            15: Integer multiply: 1 operation every 9th cycle worst case; exact timing depends
        !            16:                  on 2nd operand most significant bit position (10 bits per
        !            17:                  cycle).  Multiply unit is not pipelined, only one multiply
        !            18:                  operation in progress is allowed.
        !            19: Integer divide:          ?
        !            20: Floating-point:          Any plain 2 arithmetic instructions (such as fmul, fadd, fmadd)
        !            21:                  Latency = 4.
        !            22: Floating-point divide:
        !            23:                  ?
        !            24: Floating-point square root:
        !            25:                  ?
        !            26:
        !            27: Best possible times for the main loops:
        !            28: shift:       1.5 cycles limited by integer unit contention.
        !            29:              With 63 special loops, one for each shift count, we could
        !            30:              reduce the needed integer instructions to 2, which would
        !            31:              reduce the best possible time to 1 cycle.
        !            32: add/sub:      1.5 cycles, limited by ld/st unit contention.
        !            33: mul:         18 cycles (average) unless floating-point operations are used,
        !            34:              but that would only help for multiplies of perhaps 10 and more
        !            35:              limbs.
        !            36: addmul/submul:Same situation as for mul.