[Cfp-interest 2396] Re: WG14 IEEE 754-C binding meeting minutes 2022/03/16

[Vincent Lefevre]

On 2022-03-16 16:55:49 +0000, Rajan Bhakta wrote:
>   Carry-over action items:
>     Fred: Ask C++ what their issues with *HAS_SUBFORM are and if they are OK with obsoleting it. - Still open

I suppose that is should be *HAS_SUBNORM (in case this can be
corrected for the future version on open-std.org).

>     fma subclause title [Cfp-interest 2388]
>       David H: We called it fused since there were implementations that had fused and unfused multiply-add's.
>       Jim: In C it is fused in the sense of only one rounding. The title says "Floating" though and Pavel wants it changed to "Fused".
>       Fred: The ARM hardware does double rounding.
>         Rajan: So they are already non-conforming?
>         Fred: Yes.

This does not seem to be true. In the Assembler User Guide:

  https://www.keil.com/support/man/docs/armasm/armasm_pge1415706532461.htm

  8.3 Fused Multiply-Add extension for VFP

  The Fused Multiply-Add extension optionally extends the VFPv3
  architecture.

  It provides VFP instructions that perform multiply and accumulate
  operations with a single rounding step, so suffers from less loss
  of accuracy than performing a multiplication followed by an add.

  The fused multiply-add instructions are only available on VFP
  systems that implement the fused multiply-add extension. The VFP
  system that implements the fused multiply-add extension is VFPv4.

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