/*
 *   Code to scale dimensions.  Takes two thirty-two bit integers, multiplies
 *   them, divides them by 2^20, and returns the thirty-two bit result.
 *   The first integer, the width in FIXes, can lie between -2^24 and 2^24-1.
 *   The second integer, the scale factor, can lie between 0 and 2^27-1.
 *
 *   Here, unlike in TeX, we do the arithmetic exactly.  Since the error
 *   in the TeX arithmetic is parts per million, and since dvips makes no
 *   layout decisions, this has no effect.  (TeX stipulates that any
 *   implementation of *TeX* needs to do the arithmetic exactly as
 *   specified in TeX, but drivers need not.)
 *
 *   Since this math is special, we put it in its own file.  It is the only
 *   place in the program where such accuracy is required.
 */
#include "dvips.h" /* The copyright notice in that file is included too! */
/*
 *   The external declarations:
 */
#include "protos.h"

integer
scalewidth(register integer a, register integer b)
{
  register integer al, bl;

  if (a < 0)
     return -scalewidth(-a, b);
  if (b < 0)
     return -scalewidth(a, -b);
  al = a & 32767;
  bl = b & 32767;
  a >>= 15;
  b >>= 15;
  return ( ((al*bl/32768) + a*bl+al*b)/32 + a*b*1024);
}
