OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

[Ada] Fix off-by-one bug in underflow handling of Scaling

Browse Source 
gcc/ada/

	* libgnat/s-fatgen.adb (Scaling): Fix off-by-one bug for underflow.
This commit is contained in:
Eric Botcazou 2021-01-20 17:08:51 +01:00 committed by Pierre-Marie de Rodat
parent e18e1b5f52
commit bcc6807c4b
1 changed files with 8 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
gcc/ada/libgnat/s-fatgen.adb
View File

@ -784,7 +784,7 @@ package body System.Fat_Gen is
-- Check for gradual underflow -- Check for gradual underflow
if T'Denorm if T'Denorm
and then Adjustment >= IEEE_Emin - (Mantissa - 1) - Exp and then Adjustment >= IEEE_Emin - Mantissa - Exp
then then
Expf := IEEE_Emin; Expf := IEEE_Emin;
Expi := Exp + Adjustment - Expf; Expi := Exp + Adjustment - Expf;
@ -807,6 +807,13 @@ package body System.Fat_Gen is
Float_Word (IEEE_Ebias + Expf) * Exp_Factor; Float_Word (IEEE_Ebias + Expf) * Exp_Factor;
if Expi < 0 then if Expi < 0 then
-- Given that Expi >= -Mantissa, only -64 is problematic
if Expi = -64 then
XX := XX / 2.0;
Expi := -63;
end if;
XX := XX / T (UST.Long_Long_Unsigned (2) ** (-Expi)); XX := XX / T (UST.Long_Long_Unsigned (2) ** (-Expi));
end if; end if;