macro-op vs. micro-op

Article: Inside Barcelona: AMD's Next Generation
By: dess (dess.delete@this.nospam.com), May 21, 2007 6:15 pm
Room: Moderated Discussions
David Kanter (dkanter@realworldtech.com) on 5/21/07 wrote:
---------------------------
>In talking with architects, some use the terminology micro-op to refer to what
>AMD used to call RISCops (Rops), but are most accurately described as internal operations.
>Some of their documentation refers to macro-ops as the internal operations. I
>don't really think it matters. I choose the term that makes it easiest for the
>folks at AMD to edit/revise/comment on my article and questions.

Well, it matters if you use the same term for both AMD's and Intel's chips, in the same context, while it refers to different things. ;)

>However, Intel is a different story. First of all, the term is uop, not micro-op,

You used "uop" also on Barcelona's diagrams.

>which refers to the internal operations. In Intel terminology a macro-op is an
>x86 instruction. So macro-op fusion is the fusing of two x86 instruction (CMP+JMP).
>
>>Now I'm confused whether this happened at some places for >the Core 2 as well, or
>>those are really 4 micro-ops, in which case the Barcelona >is the wider one.
>
>Decoding always maps the contents of the Icache (x86 instructions) to the internal
>operations and operands of the processor in question.
>
>AMD has 3 decoders, Intel has 4 decoders. AMD can 3 operations/cycle, Intel can
>rename 4. Counting execution units is a little tricky since AMD likes to count
>their separate AGUs as functional units, while Intel considers them part of the
>memory pipelines. Intel can retire 4 operations, AMD can retire 3.
>
>At the end of the day, the Core2 is theoretically wider. However, it's unclear
>to what extent this will be true in practice.
>
>DK

Taking into account that AMD's 3 decoders are responsible of decoding 95% of the instruction set/modes (the uCode Engine works with the remaining 5%, as one more decoder, but it won't work parallel with the other 3), and emit up to 2 micro-ops each, while 3 of Intel's 4 decoders are for more simple instructions, and so emit one uop, Intel's is wider only in case of more simple instructions are being used.

Moreover, AFAIK, AMD's Pack Buffer emits 3 _macro-ops_, whose can contain up to 6 micro-ops, while Intel's path is 4 _uop_. Or is this "uop" a macro-op in AMD's terms?
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  microops vs macroops on page 4Peter Lund2007/05/17 12:04 PM
    microops vs macroops on page 4David Kanter2007/05/21 04:51 PM
      microops vs macroops on page 4EduardoS2007/05/21 05:42 PM
        microops vs macroops on page 4dess2007/05/21 07:00 PM
  Barcelona Article OnlinePeter Lund2007/05/17 12:25 PM
  macro-op vs. micro-opdess2007/05/21 07:24 AM
    macro-op vs. micro-opDavid Kanter2007/05/21 04:38 PM
      macro-op vs. micro-opdess2007/05/21 06:15 PM
        macro-op vs. micro-opDavid Kanter2007/05/22 12:11 AM
          macro-op vs. micro-opdess2007/05/22 03:56 AM
            macro-op vs. micro-opGipsel2007/05/22 05:05 AM
              macro-op vs. micro-opdess2007/05/22 05:52 AM
                macro-op vs. micro-opanonymous2007/05/22 06:14 AM
                  macro-op vs. micro-opdess2007/05/22 06:44 AM
                    macro-op vs. micro-opEduardoS2007/05/22 02:19 PM
                      macro-op vs. micro-opdess2007/05/24 08:52 AM
            Stop comparing apples to orangesEduardoS2007/05/22 02:30 PM
              Stop comparing apples to orangesdess2007/05/22 04:09 PM
                Stop comparing apples to orangesdess2007/05/22 04:30 PM
                Stop comparing apples to orangesEduardoS2007/05/22 04:31 PM
                  Stop comparing... apples to oranges?dess2007/05/24 09:30 AM
              Stop comparing apples to orangesanonymous2007/05/22 08:12 PM
                Stop comparing apples to orangesEduardoS2007/05/23 02:50 PM
          macro-op vs. micro-opanonymous2007/05/22 06:08 AM
            macro-op vs. micro-opdess2007/05/22 06:40 AM
              macro-op vs. micro-opanonymous2007/05/22 06:48 AM
      macro-op vs. micro-opdess2007/05/21 08:30 PM
        macro-op vs. micro-opanonymous2007/05/22 06:44 AM
          macro-op vs. micro-opdess2007/05/24 09:38 AM
      macro-op vs. micro-opMichael S2007/05/22 05:26 AM
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