sflop.m

SFLOP simulates a floating point operation x op y where op = +, -, *, /

%  PURPOSE:
%  SFLOP  simulates a floating point operation
% 
%       x   op   y      where  op = +, -, *, / 
% 
%  In chopping or rounding arithmetic using an
%  m  digit mantissa, base 10, and an unrestricted 
%  exponent range. (sflop: Simulate FLOating Point 
%  operation.) For more details on the how the floating
%  point representation of a number is computed see
%  the function  sfl.
% 
% 
%  CALLING SEQUENCE:
%   
%  function [res] = sflop( x, y, m, arith, op )
%
%  INPUT:
% 
%  x      real 
%         argument in the floating point operation
% 
%  y      real
%         argument in the floating point operation
% 
%  m      integer
%         mantissa length
% 
%  arith  string
%         arith = 'c'   chopped arithmetic
%         arith = 'r'   rounded arithmetic
% 
%  op     string
%         type of floating point operation
%         op    = '+'  or  '-'  or  '*'  or  '/'
% 
% 
%  OUTPUT:
% 
%  res    real
%         result of the floating point operation
% 
%
%
%
%  Matthias Heinkenschloss
%  Department of Computational and Applied Mathematics
%  Rice University
%  Feb 12, 2001
%
% 

     
function [res] = sflop( x, y, m, arith, op )

%  compute floating point represenation of x  and  y 

xfl = sfl( x, m, arith);
yfl = sfl( y, m, arith);

%  perform operation to 'full' accuracy

if( op == '+' )  
  z = xfl + yfl;
end
if( op == '-' )  
  z = xfl - yfl;
end
if( op == '*' )  
  z = xfl .* yfl;
end
if( op == '/' )    
  z = xfl ./ yfl;
end

%  round/chopp the result

res = sfl( z, m, arith);