Fix a bug about the iSCSI DHCP dependency issue.

[mirror_edk2.git] / StdLib / LibC / Math / e_rem_pio2.c

/* @(#)e_rem_pio2.c 5.1 93/09/24 */\r
/*\r
 * ====================================================\r
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.\r
 *\r
 * Developed at SunPro, a Sun Microsystems, Inc. business.\r
 * Permission to use, copy, modify, and distribute this\r
 * software is freely granted, provided that this notice\r
 * is preserved.\r
 * ====================================================\r
 */\r
#include  <LibConfig.h>\r
#include  <sys/EfiCdefs.h>\r
#if defined(LIBM_SCCS) && !defined(lint)\r
__RCSID("$NetBSD: e_rem_pio2.c,v 1.11 2002/05/26 22:01:52 wiz Exp $");\r
#endif\r
\r
/* __ieee754_rem_pio2(x,y)\r
 *\r
 * return the remainder of x rem pi/2 in y[0]+y[1]\r
 * use __kernel_rem_pio2()\r
 */\r
\r
#include "math.h"\r
#include "math_private.h"\r
\r
/*\r
 * Table of constants for 2/pi, 396 Hex digits (476 decimal) of 2/pi\r
 */\r
static const int32_t two_over_pi[] = {\r
0xA2F983, 0x6E4E44, 0x1529FC, 0x2757D1, 0xF534DD, 0xC0DB62,\r
0x95993C, 0x439041, 0xFE5163, 0xABDEBB, 0xC561B7, 0x246E3A,\r
0x424DD2, 0xE00649, 0x2EEA09, 0xD1921C, 0xFE1DEB, 0x1CB129,\r
0xA73EE8, 0x8235F5, 0x2EBB44, 0x84E99C, 0x7026B4, 0x5F7E41,\r
0x3991D6, 0x398353, 0x39F49C, 0x845F8B, 0xBDF928, 0x3B1FF8,\r
0x97FFDE, 0x05980F, 0xEF2F11, 0x8B5A0A, 0x6D1F6D, 0x367ECF,\r
0x27CB09, 0xB74F46, 0x3F669E, 0x5FEA2D, 0x7527BA, 0xC7EBE5,\r
0xF17B3D, 0x0739F7, 0x8A5292, 0xEA6BFB, 0x5FB11F, 0x8D5D08,\r
0x560330, 0x46FC7B, 0x6BABF0, 0xCFBC20, 0x9AF436, 0x1DA9E3,\r
0x91615E, 0xE61B08, 0x659985, 0x5F14A0, 0x68408D, 0xFFD880,\r
0x4D7327, 0x310606, 0x1556CA, 0x73A8C9, 0x60E27B, 0xC08C6B,\r
};\r
\r
static const int32_t npio2_hw[] = {\r
0x3FF921FB, 0x400921FB, 0x4012D97C, 0x401921FB, 0x401F6A7A, 0x4022D97C,\r
0x4025FDBB, 0x402921FB, 0x402C463A, 0x402F6A7A, 0x4031475C, 0x4032D97C,\r
0x40346B9C, 0x4035FDBB, 0x40378FDB, 0x403921FB, 0x403AB41B, 0x403C463A,\r
0x403DD85A, 0x403F6A7A, 0x40407E4C, 0x4041475C, 0x4042106C, 0x4042D97C,\r
0x4043A28C, 0x40446B9C, 0x404534AC, 0x4045FDBB, 0x4046C6CB, 0x40478FDB,\r
0x404858EB, 0x404921FB,\r
};\r
\r
/*\r
 * invpio2:  53 bits of 2/pi\r
 * pio2_1:   first  33 bit of pi/2\r
 * pio2_1t:  pi/2 - pio2_1\r
 * pio2_2:   second 33 bit of pi/2\r
 * pio2_2t:  pi/2 - (pio2_1+pio2_2)\r
 * pio2_3:   third  33 bit of pi/2\r
 * pio2_3t:  pi/2 - (pio2_1+pio2_2+pio2_3)\r
 */\r
\r
static const double\r
zero =  0.00000000000000000000e+00, /* 0x00000000, 0x00000000 */\r
half =  5.00000000000000000000e-01, /* 0x3FE00000, 0x00000000 */\r
two24 =  1.67772160000000000000e+07, /* 0x41700000, 0x00000000 */\r
invpio2 =  6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */\r
pio2_1  =  1.57079632673412561417e+00, /* 0x3FF921FB, 0x54400000 */\r
pio2_1t =  6.07710050650619224932e-11, /* 0x3DD0B461, 0x1A626331 */\r
pio2_2  =  6.07710050630396597660e-11, /* 0x3DD0B461, 0x1A600000 */\r
pio2_2t =  2.02226624879595063154e-21, /* 0x3BA3198A, 0x2E037073 */\r
pio2_3  =  2.02226624871116645580e-21, /* 0x3BA3198A, 0x2E000000 */\r
pio2_3t =  8.47842766036889956997e-32; /* 0x397B839A, 0x252049C1 */\r
\r
int32_t\r
__ieee754_rem_pio2(double x, double *y)\r
{\r
  double z,w,t,r,fn;\r
  double tx[3];\r
  int32_t e0,i,j,nx,n,ix,hx;\r
  u_int32_t low;\r
\r
  z = 0;\r
  GET_HIGH_WORD(hx,x);    /* high word of x */\r
  ix = hx&0x7fffffff;\r
  if(ix<=0x3fe921fb)   /* |x| ~<= pi/4 , no need for reduction */\r
      {y[0] = x; y[1] = 0; return 0;}\r
  if(ix<0x4002d97c) {  /* |x| < 3pi/4, special case with n=+-1 */\r
      if(hx>0) {\r
    z = x - pio2_1;\r
    if(ix!=0x3ff921fb) {  /* 33+53 bit pi is good enough */\r
        y[0] = z - pio2_1t;\r
        y[1] = (z-y[0])-pio2_1t;\r
    } else {    /* near pi/2, use 33+33+53 bit pi */\r
        z -= pio2_2;\r
        y[0] = z - pio2_2t;\r
        y[1] = (z-y[0])-pio2_2t;\r
    }\r
    return 1;\r
      } else {  /* negative x */\r
    z = x + pio2_1;\r
    if(ix!=0x3ff921fb) {  /* 33+53 bit pi is good enough */\r
        y[0] = z + pio2_1t;\r
        y[1] = (z-y[0])+pio2_1t;\r
    } else {    /* near pi/2, use 33+33+53 bit pi */\r
        z += pio2_2;\r
        y[0] = z + pio2_2t;\r
        y[1] = (z-y[0])+pio2_2t;\r
    }\r
    return -1;\r
      }\r
  }\r
  if(ix<=0x413921fb) { /* |x| ~<= 2^19*(pi/2), medium size */\r
      t  = fabs(x);\r
      n  = (int32_t) (t*invpio2+half);\r
      fn = (double)n;\r
      r  = t-fn*pio2_1;\r
      w  = fn*pio2_1t;  /* 1st round good to 85 bit */\r
      if(n<32&&ix!=npio2_hw[n-1]) {\r
    y[0] = r-w; /* quick check no cancellation */\r
      } else {\r
          u_int32_t high;\r
          j  = ix>>20;\r
          y[0] = r-w;\r
    GET_HIGH_WORD(high,y[0]);\r
          i = j-((high>>20)&0x7ff);\r
          if(i>16) {  /* 2nd iteration needed, good to 118 */\r
        t  = r;\r
        w  = fn*pio2_2;\r
        r  = t-w;\r
        w  = fn*pio2_2t-((t-r)-w);\r
        y[0] = r-w;\r
        GET_HIGH_WORD(high,y[0]);\r
        i = j-((high>>20)&0x7ff);\r
        if(i>49)  { /* 3rd iteration need, 151 bits acc */\r
          t  = r; /* will cover all possible cases */\r
          w  = fn*pio2_3;\r
          r  = t-w;\r
          w  = fn*pio2_3t-((t-r)-w);\r
          y[0] = r-w;\r
        }\r
    }\r
      }\r
      y[1] = (r-y[0])-w;\r
      if(hx<0)  {y[0] = -y[0]; y[1] = -y[1]; return -n;}\r
      else   return n;\r
  }\r
    /*\r
     * all other (large) arguments\r
     */\r
  if(ix>=0x7ff00000) {    /* x is inf or NaN */\r
      y[0]=y[1]=x-x; return 0;\r
  }\r
    /* set z = scalbn(|x|,ilogb(x)-23) */\r
  GET_LOW_WORD(low,x);\r
  SET_LOW_WORD(z,low);\r
  e0  = (ix>>20)-1046;  /* e0 = ilogb(z)-23; */\r
  SET_HIGH_WORD(z, ix - ((int32_t)(e0<<20)));\r
  for(i=0;i<2;i++) {\r
    tx[i] = (double)((int32_t)(z));\r
    z     = (z-tx[i])*two24;\r
  }\r
  tx[2] = z;\r
  nx = 3;\r
  while(tx[nx-1]==zero) nx--; /* skip zero term */\r
  n  =  __kernel_rem_pio2(tx,y,e0,nx,2,two_over_pi);\r
  if(hx<0) {y[0] = -y[0]; y[1] = -y[1]; return -n;}\r
  return n;\r
}\r