#include <assert.h>
#include <stdio.h>

#define MORT 24

#define mult16(x,k) \
    ((x>>16)*k+((((x&0xFFFF)*k)+(1<<15))>>16))

static int val[65];

void init_amortize_tab()
{
  unsigned int i,v;
  v=1<<16;
  val[0]=v;
  for(i=1;i<=32;++i) {
    v=((v*(MORT-1))+(MORT/2))/MORT;
    val[i]=v;
    printf("tab %d %d\n",i,v);
  }
  for(i=33;i<=64;++i) {
    v=((v*(val[32]))+(1<<15))>>16;
    val[i]=v;
    printf("tab %d %d\n",i,v);
  }
}

int amortize(int b, int d)
     /* returns b*((MORT-1)/MORT)**d, that is, b depreciated for d turns
	at 1/MORT per turn.  Requires val[] to have been set up by 
	init_amortize_tab()
	MORT must be >0 and < 2**15. (given 32-bit int)   d must be >= 0
	
	four or five times faster than
	static double MULTIPLIER = ((double)MORT - 1) / MORT;
	return (int)(0.5 + ( b * pow( MULTIPLIER, d )));
	at minor cost in accuracy
     */
{
  int s=1;
  int rough;

  assert(d>=0);
  if ( b < 0 ) { s=-1; b *= s; }
  if ( d <= 32 ) 
    return s*mult16(b,val[d]);
  while (( d > 1024 ) && b ) {
    b=mult16(b,val[64]);
    d-=1024;
  }
  rough=mult16(b,val[d/32+31]);
  return s*mult16(rough,val[d%32]);
}