paweld/fpc
1
0
Fork 0
mirror of https://gitlab.com/freepascal.org/fpc/source.git synced 2025-04-07 09:47:52 +02:00
Code Issues Packages Projects Releases Wiki Activity

+ added helper isabspowerof2, which checks whether abs(value) is a power of 2

Browse Source 
git-svn-id: trunk@36796 -
This commit is contained in:
nickysn 2017-07-26 16:08:31 +00:00
parent 7ee567fcca
commit 4b00414183
1 changed files with 15 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
compiler/cutils.pas
View File

@ -108,6 +108,10 @@ interface
}
function ispowerof2(value : int64;out power : longint) : boolean;
function ispowerof2(const value : Tconstexprint;out power : longint) : boolean;
{# Returns true if abs(value) is a power of 2, the actual
exponent value is returned in power.
}
function isabspowerof2(const value : Tconstexprint;out power : longint) : boolean;
function nextpowerof2(value : int64; out power: longint) : int64;
{$ifdef VER2_6} { only 2.7.1+ has a popcnt function in the system unit }
function PopCnt(AValue : Byte): Byte;
@ -929,6 +933,17 @@ implementation
end;
function isabspowerof2(const value : Tconstexprint;out power : longint) : boolean;
begin
if ispowerof2(value,power) then
result:=true
else if value.signed and (value.svalue<0) and (value.svalue<>low(int64)) and ispowerof2(-value.svalue,power) then
result:=true
else
result:=false;
end;
function nextpowerof2(value : int64; out power: longint) : int64;
{
returns the power of 2 >= value