title: IEEE_UNDERFLOW_FLAG IEEE_DENORMAL in Fortran 77
body: <p>I am new to Fortran and coding in general so I apologize if my terminology is not correct.</p>
  
  <p>I am using a Linux machine with the gfortran compiler.</p>
  
  <p>I am doing research this summer which involves me getting a program written in about 1980 working again. It is written in Fortran 77. I have all the code as well as some documentation about it. </p>
  
  <p>In its current form it I am receiving a "IEEE_UNDERFLOW_FLAG IEEE_DENORMAL" error. My first thought is that this code was meant to be developed under a different environment/architecture.</p>
  
  <p>The documentation states “This program was designed to run on the HARRIS computer system. It also can be run on VAX system if the single precision variables are changed into double precision variables both in the main code and the subroutine package.”</p>
  
  <p>I have tried changing the single precision variables to double precision variables, but I may have done that wrong. If this is the correct thing to do any insight would be great.</p>
  
  <p>I have also tried compiling the coding with -std=legacy and -m32. I receive the same error from this as well.</p>
  
  <p>Any advice to get me going in the right direction would be greatly appreciated.   </p>