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VAX EMUL?

Is the VAX's EMUL instruction a multiply-add? Its description says: "The multiplicand operand is multiplied by the multiplier operand, giving a double-length result. The addend operand is sign extended to double length and added to the result. The product operand is replaced by the final result." That sounds like a description of a multiply-add. 67.39.207.45 13:28, 16 September 2007 (UTC)

No, because the addend is too short to be useful as an accumulator. Dicklyon (talk) 21:26, 6 June 2011 (UTC)

Division and square root

Because of this instruction there is no need for a hardware divide or square root unit, since they can both be implemented efficiently in software using the FMA.

How is this done? --Abdull (talk) 19:56, 19 June 2008 (UTC)

I guess this is alluding to division (digital)#Fast division methods, the methods of computing square roots#Babylonian method, and Methods of computing square roots#Iterative methods for reciprocal square roots, all of which generate their results in "a few" iterations of multiply-and-add.

What's a good way of pointing this out without diverging too far from the topic of this article? --68.0.124.33 (talk) 15:44, 17 September 2008 (UTC)

Dry explanation

One should try to redefine the first definition of fused add, now it's useless... —Preceding unsigned comment added by 212.77.163.102 (talk) 13:49, 6 January 2011 (UTC)

Nounize it?

Instead of Multiply–accumulate, should we move it to a noun? Multiplier–accumulator? Or Multiply–accumulate instruction? What think? Dicklyon (talk) 03:05, 13 June 2011 (UTC)

Multiply-add would be more common. Certainly not accumulator or adder - that would refer to an actual bit of hardware. No need to say instruction or operation. Dmcq (talk) 05:53, 13 June 2011 (UTC)

In the hardware and DSP biz, multiplier–accumulator is a common topic (e.g. in contexts where there are no op codes or such); it presently redirects to this verb-named article. Should it have its own article then? I understand that this verb is commonly used to stand for the operation or instruction, but the article title guidelines strongly suggest noun forms for titles. Couldn't we supply the implied noun, an "operation" as the lead says? I should have suggested Multiply–accumulate operation among the alternative noun forms. Dicklyon (talk) 14:57, 13 June 2011 (UTC)

Even sticking with multiply-accumulate if you look at the first page of things google returns you get algorithm, unit, architecture, operation, four uses as a noun, plus multiply accumulator. So just on its own would seem to be the most common. Dmcq (talk) 16:07, 13 June 2011 (UTC)

But on its own isn't a noun (uses as a noun just omit the noun, whether operation, unit, etc.); titles are supposed to be topics, expressed as nouns, not common subphrases of other sorts. See WP:NOUN. Dicklyon (talk) 01:45, 14 June 2011 (UTC)

If people use it as a noun it's a noun. Why send people through redirects or decide between the various possible nouns that can follow? The IEEE 2008 standard says 'Addition, subtraction, multiplication, division, fused multiply add, square root, compare, and other operations' for instance. If it is good enough for a standard it is good enough for us I think. Dmcq (talk) 09:30, 14 June 2011 (UTC)

That sentence doesn't strike you as oddly non-parallel with a verb form in the list of nouns? Why refer to an "operation" by the verb form of what it does, just because some others sometimes do? What's the objection to multiply–accumulate operation? How is sending people through redirects a disadvantage? Dicklyon (talk) 15:28, 14 June 2011 (UTC)

It sounds perfectly okay to me. I don't think people normally stick operation onto it. In fact sticking operation at the end sounds clunky to me and I'd only do it to specially emphasise the operation part as opposed something like using a multiply-add to do something or a multiply-accumulate unit. Dmcq (talk) 17:14, 14 June 2011 (UTC)

I understand how one accustomed to a term can interpret a verb as a noun, or whatever. But we're writing for an audience who are often not that familiar, so it's a good idea to use standard grammar and punctuation to help clarify what we mean. Perhaps I'll do an RM and see if there are other opinions. Dicklyon (talk) 20:44, 14 June 2011 (UTC)

Requested move

The request to rename this article to Multiply–accumulate operation has been carried out. If the page title has consensus, be sure to close this discussion using {{subst:RM top|'''page moved'''.}} and {{subst:RM bottom}} and remove the {{Requested move/dated|…}} tag, or replace it with the {{subst:Requested move/end|…}} tag.

Multiply-accumulate → Multiply–accumulate operation – I propose we change the verb title to the implied noun, per WP:NOUN (and change the hyphen to an en dash while we're at it, per WP:DASH). I'm listing this as a possibly controversial move, since I got pushback from an editor in my suggestion above. The "operation" seems to be the most common noun that goes with this article, and it's what the lead says the article is about. It's also general enough to support a section on a "multiplier–accumulator" or "multiply–accumulate unit". Dicklyon (talk) 20:56, 14 June 2011 (UTC)

• Requested moves