[Info-vax] xcc long double implementation

[Arne Vajhøj]

On 9/3/2021 10:12 AM, Stephen Hoffman wrote:
> On 2021-09-03 12:03:57 +0000, David Jones said:
> 
>> The long double data type on the X86 cross compiler is broken, 
>> seriously broken. I'm just curious about what format they intend it to 
>> be. The sizeof operator says it's 16 bytes, implying it's using 
>> 128-bits. Are they assuming the assuming the hardware doesn't support 
>> 128-bit fp and trying to do a software implementation?
> 
> Cross compilers are such sour sorrow.
> 
> long double is... weird... on x86.
> 
> It's usually 80 bits of actual floating point content stored inside a 
> larger 12- or 16-byte bag, but it's also sometimes "just" double, 
> depending on the compiler.
> 
> I'd suspect VSI is planning to follow gcc and clang here, and will be 
> using the x87 80-bit representation and not the 64-bit double 
> representation, but haven't confirmed.

x86 had the weird 80 bit FP's.

But wasn't those ditched in x86-64?

Arne