Re: Procps in core-updates

[Michael Schierl <schierlm@gmx.de>]

Hello Andreas,

Am 20.03.2023 um 15:54 schrieb Andreas Enge:
> Hello Michael,
>
> I am attaching a simplified C file and the corresponding assembly
> output; which I cannot read, but there are differences between the two
> invocations of fprintf.

Seems that you accidentally attached the object file (binary) instead of
the assembly output. :-)

> The weirdest thing is that actually the value is the integer 123. So it
> should be stored in any kind of register exactly.

123 as a normalized binary floating point number would be

1.921875 × 2⁶

and you would have to represent the mantissa in binary (1.111011₂).
Still this should fit into most floating point registers easily.

But possibly the value computed by the algorithm of parsing the number
resulted in e.g.

1.111011000000000000000000000000000000000000000000000001011₂ × 2⁶

which is still 123 when converted back to a 52-bit mantissa, but
something ever so slightly larger when treated as an 80-bit float with
64 bits mantissa.

Or maybe I'm missing something :-)


Regards,


Michael