arch/mips/math-emu/sp_flong.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* IEEE754 floating point arithmetic
   3  * single precision
   4  */
   5 /*
   6  * MIPS floating point support
   7  * Copyright (C) 1994-2000 Algorithmics Ltd.
   8  */
   9
  10 #include "ieee754sp.h"
  11
  12 union ieee754sp ieee754sp_flong(s64 x)
  13 {
  14         u64 xm;         /* <--- need 64-bit mantissa temp */
  15         int xe;
  16         int xs;
  17
  18         ieee754_clearcx();
  19
  20         if (x == 0)
  21                 return ieee754sp_zero(0);
  22         if (x == 1 || x == -1)
  23                 return ieee754sp_one(x < 0);
  24         if (x == 10 || x == -10)
  25                 return ieee754sp_ten(x < 0);
  26
  27         xs = (x < 0);
  28         if (xs) {
  29                 if (x == (1ULL << 63))
  30                         xm = (1ULL << 63);      /* max neg can't be safely negated */
  31                 else
  32                         xm = -x;
  33         } else {
  34                 xm = x;
  35         }
  36         xe = SP_FBITS + 3;
  37
  38         if (xm >> (SP_FBITS + 1 + 3)) {
  39                 /* shunt out overflow bits
  40                  */
  41                 while (xm >> (SP_FBITS + 1 + 3)) {
  42                         SPXSRSX1();
  43                 }
  44         } else {
  45                 /* normalize in grs extended single precision */
  46                 while ((xm >> (SP_FBITS + 3)) == 0) {
  47                         xm <<= 1;
  48                         xe--;
  49                 }
  50         }
  51         return ieee754sp_format(xs, xe, xm);
  52 }