OT: floats

[Timon Gehr]

On 5/25/24 00:21, Walter Bright wrote:
> On 5/24/2024 4:51 AM, Timon Gehr wrote:
>> (E.g, D's specified floating-point semantics are completely insane,
> 
> I presume you are talking about doing intermediate computations as 80 
> bit floats. This was inevitable with the x86 prior to XMM. With XMM, 
> floats and doubles are evaluated with XMM instructions that do 32/64 bit 
> respectively.
> 

It was avoidable, as even the x87 allows controlling the mantissa size 
(which is insufficient but "more" correct) or flushing floats and 
doubles to memory.

D compilers are allowed by the spec e.g. to use 64-bit XMM registers to 
compute with 32-bit float intermediates, with incorrect rounding behavior.