[Octave-bug-tracker] [bug #59830] Architecture-dependent results for arithmetic operations involving NA

[Rafael Laboissiere]

Follow-up Comment #11, bug #59830 (project octave):


[comment #8 comment #8:]
> Instead, you might try re-defining the high word of Octave NA so that the
quiet signaling bit is '0' to match MIPS.  As another test, I would ask you to
try changing liboctave/util/lo-ieee.h.
> 
> 
> diff -r e4c152e827aa liboctave/util/lo-ieee.h
> --- a/liboctave/util/lo-ieee.h        Thu Jan 07 18:34:18 2021 +0100
> +++ b/liboctave/util/lo-ieee.h        Fri Jan 08 14:09:31 2021 -0800
> @@ -69,7 +69,7 @@ typedef union
>  
>  #define LO_IEEE_NA_HW_OLD 0x7ff00000
>  #define LO_IEEE_NA_LW_OLD 1954
> -#define LO_IEEE_NA_HW 0x7FF840F4
> +#define LO_IEEE_NA_HW 0x7FF040F4
>  #define LO_IEEE_NA_LW 0x40000000
>  #define LO_IEEE_NA_FLOAT   0x7FC207A2
>  
> 
> 
> Apply the patch with 'patch -p1 < mypatch' and then re-compile.
> 
> Try
> 
> 
> format native-bit
> x = NA
> y = x / 4
> isna (y)
> 

I recompiled Octave on a Debian mips64el system with Rik's patch above.  It
yields this:


octave:1> format native-bit
octave:2> x = NA
x = 0000000000000000000000000000001000101111000000100000111111111110
octave:3> y = x / NA
y = 0000000000000000000000000000001000101111000000100000111111111110
octave:4> isna (y)
ans = 10000000


Just for the record, this is what happens without the patch:


octave:1> format native-bit
octave:2> x = NA
x = 0000000000000000000000000000001000101111000000100001111111111110
octave:3> y = x / NA
y = 1111111111111111111111111111111111111111111111111110111111111110
octave:4> isna (y)
ans = 00000000



    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?59830>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/