newlib/libm/machine/amdgcn/v64sf_scalbn.c

   1 /*
   2  * Copyright 2023 Siemens
   3  *
   4  * The authors hereby grant permission to use, copy, modify, distribute,
   5  * and license this software and its documentation for any purpose, provided
   6  * that existing copyright notices are retained in all copies and that this
   7  * notice is included verbatim in any distributions.  No written agreement,
   8  * license, or royalty fee is required for any of the authorized uses.
   9  * Modifications to this software may be copyrighted by their authors
  10  * and need not follow the licensing terms described here, provided that
  11  * the new terms are clearly indicated on the first page of each file where
  12  * they apply.
  13  */
  14
  15 /*
  16  * ====================================================
  17  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
  18  *
  19  * Developed at SunPro, a Sun Microsystems, Inc. business.
  20  * Permission to use, copy, modify, and distribute this
  21  * software is freely granted, provided that this notice
  22  * is preserved.
  23  * ====================================================
  24  */
  25
  26 /* Based on newlib/libm/common/sf_scalbn.c in Newlib.  */
  27
  28 #include "amdgcnmach.h"
  29 #include <limits.h>
  30 #include <float.h>
  31
  32 #if INT_MAX > 50000
  33 #define OVERFLOW_INT 50000
  34 #else
  35 #define OVERFLOW_INT 30000
  36 #endif
  37
  38 static const float
  39 two25   =  3.355443200e+07,     /* 0x4c000000 */
  40 twom25  =  2.9802322388e-08,    /* 0x33000000 */
  41 huge   = 1.0e+30,
  42 tiny   = 1.0e-30;
  43
  44 v64sf v64sf_copysignf_aux (v64sf, v64sf, v64si);
  45
  46 DEF_VS_MATH_FUNC (v64sf, scalbnf, v64sf x, v64si n)
  47 {
  48   FUNCTION_INIT (v64sf);
  49
  50   const v64sf huge_v = VECTOR_INIT ((float) huge);
  51   const v64sf tiny_v = VECTOR_INIT ((float) tiny);
  52
  53   v64si ix;
  54   GET_FLOAT_WORD (ix, x, NO_COND);
  55   v64si hx = ix & 0x7fffffff;
  56   v64si k = hx >> 23;           /* extract exponent */
  57   VECTOR_IF (FLT_UWORD_IS_ZERO(hx), cond)
  58     VECTOR_RETURN (x, cond);
  59   VECTOR_ENDIF
  60   VECTOR_IF (~FLT_UWORD_IS_FINITE(hx), cond)    /* NaN or Inf */
  61     VECTOR_RETURN (x + x, cond);
  62   VECTOR_ENDIF
  63   VECTOR_IF (FLT_UWORD_IS_SUBNORMAL (hx), cond);
  64     VECTOR_COND_MOVE (x, x * two25, cond);
  65     GET_FLOAT_WORD (ix, x, cond);
  66     VECTOR_COND_MOVE (k, ((ix & 0x7f800000) >> 23) - 25, cond);
  67     VECTOR_IF2 (n < -50000, cond2, cond)        /*underflow*/
  68       VECTOR_RETURN (tiny * x, cond2);
  69     VECTOR_ENDIF
  70   VECTOR_ENDIF
  71   VECTOR_IF (n > OVERFLOW_INT, cond)    // in case integer overflow in n+k
  72     VECTOR_RETURN (huge_v * v64sf_copysignf_aux (huge_v, x, __mask), cond);
  73   VECTOR_ENDIF
  74   k = k + n;
  75   VECTOR_IF (k > FLT_LARGEST_EXP, cond)         /* overflow */
  76     VECTOR_RETURN (huge_v * v64sf_copysignf_aux (huge_v, x, __mask), cond);
  77   VECTOR_ENDIF
  78   VECTOR_IF (k > 0, cond)                       /* normal result */
  79     SET_FLOAT_WORD (x, (ix & 0x807fffff) | (k << 23), cond);
  80     VECTOR_RETURN (x, cond);
  81   VECTOR_ENDIF
  82   VECTOR_IF (k < FLT_SMALLEST_EXP, cond)        /*underflow*/
  83     VECTOR_RETURN (tiny_v * v64sf_copysignf_aux (tiny_v, x, __mask),
  84                    k < FLT_SMALLEST_EXP);
  85   VECTOR_ENDIF
  86
  87   k += 25;                              /* subnormal result */
  88   SET_FLOAT_WORD (x, (ix & 0x807fffff) | (k << 23), NO_COND);
  89   VECTOR_RETURN (x * twom25, NO_COND);
  90
  91   FUNCTION_RETURN;
  92 }