sp_fdp.c 2.1 KB

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  1. /* IEEE754 floating point arithmetic
  2. * single precision
  3. */
  4. /*
  5. * MIPS floating point support
  6. * Copyright (C) 1994-2000 Algorithmics Ltd.
  7. *
  8. * ########################################################################
  9. *
  10. * This program is free software; you can distribute it and/or modify it
  11. * under the terms of the GNU General Public License (Version 2) as
  12. * published by the Free Software Foundation.
  13. *
  14. * This program is distributed in the hope it will be useful, but WITHOUT
  15. * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16. * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  17. * for more details.
  18. *
  19. * You should have received a copy of the GNU General Public License along
  20. * with this program; if not, write to the Free Software Foundation, Inc.,
  21. * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22. *
  23. * ########################################################################
  24. */
  25. #include "ieee754sp.h"
  26. ieee754sp ieee754sp_fdp(ieee754dp x)
  27. {
  28. COMPXDP;
  29. ieee754sp nan;
  30. EXPLODEXDP;
  31. CLEARCX;
  32. FLUSHXDP;
  33. switch (xc) {
  34. case IEEE754_CLASS_SNAN:
  35. SETCX(IEEE754_INVALID_OPERATION);
  36. return ieee754sp_nanxcpt(ieee754sp_indef(), "fdp");
  37. case IEEE754_CLASS_QNAN:
  38. nan = buildsp(xs, SP_EMAX + 1 + SP_EBIAS, (u32)
  39. (xm >> (DP_MBITS - SP_MBITS)));
  40. if (!ieee754sp_isnan(nan))
  41. nan = ieee754sp_indef();
  42. return ieee754sp_nanxcpt(nan, "fdp", x);
  43. case IEEE754_CLASS_INF:
  44. return ieee754sp_inf(xs);
  45. case IEEE754_CLASS_ZERO:
  46. return ieee754sp_zero(xs);
  47. case IEEE754_CLASS_DNORM:
  48. /* can't possibly be sp representable */
  49. SETCX(IEEE754_UNDERFLOW);
  50. SETCX(IEEE754_INEXACT);
  51. if ((ieee754_csr.rm == IEEE754_RU && !xs) ||
  52. (ieee754_csr.rm == IEEE754_RD && xs))
  53. return ieee754sp_xcpt(ieee754sp_mind(xs), "fdp", x);
  54. return ieee754sp_xcpt(ieee754sp_zero(xs), "fdp", x);
  55. case IEEE754_CLASS_NORM:
  56. break;
  57. }
  58. {
  59. u32 rm;
  60. /* convert from DP_MBITS to SP_MBITS+3 with sticky right shift
  61. */
  62. rm = (xm >> (DP_MBITS - (SP_MBITS + 3))) |
  63. ((xm << (64 - (DP_MBITS - (SP_MBITS + 3)))) != 0);
  64. SPNORMRET1(xs, xe, rm, "fdp", x);
  65. }
  66. }