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sumit_tuwien

Potential division by zero in SystemC Library

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Hi All,

 

There are many points where there are division by 0 observed and can show up any time. We have found no protection mechanism for that.

 

One such example  (sysc/datatypes/fx/scfx_rep.cpp) : 

 

     switch( numrep )

    {
case SC_BIN:
case SC_BIN_US:
case SC_CSD:
   step = 1;
  break;
case SC_OCT:
case SC_OCT_US:
   step = 3;
   break;
case SC_HEX:
case SC_HEX_US:
   step = 4;
   break;
default:
   step = 0;
    }
 
    msb = (int) ceil( double( msb + 1 ) / step ) * step - 1;
 
    lsb = (int) floor( double( lsb ) / step ) * step;
 
    if( msb < 0 )
    {
s += '.';
if( fmt == SC_F )
{
   int sign = ( b.is_neg() ) ? ( 1 << step ) - 1 : 0;
   for( int i = ( msb + 1 ) / step; i < 0; i ++ )
   {
 
if numrep defaults, there will be division by zero. Functionally it never showed up, still there is a chance this will be triggered. 
 
We can share the complete lint report if you are interested.
 
Regards, Sumit

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As in the other post about dereferencing NULL pointers, I suspect that (all of?) these reports are false positives as well.

 

If you want to silence the linter about these, just add calls to explicitily non-returning functions like std::terminate. On the other hand, a division by zero will usually abort your simulation as well. ;-)

 

/Philipp

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