sp_tlong.c 2.9 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. s64 ieee754sp_tlong(ieee754sp x)
  27. {
  28. COMPXDP; /* <-- need 64-bit mantissa tmp */
  29. CLEARCX;
  30. EXPLODEXSP;
  31. FLUSHXSP;
  32. switch (xc) {
  33. case IEEE754_CLASS_SNAN:
  34. case IEEE754_CLASS_QNAN:
  35. case IEEE754_CLASS_INF:
  36. SETCX(IEEE754_INVALID_OPERATION);
  37. return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
  38. case IEEE754_CLASS_ZERO:
  39. return 0;
  40. case IEEE754_CLASS_DNORM:
  41. case IEEE754_CLASS_NORM:
  42. break;
  43. }
  44. if (xe >= 63) {
  45. /* look for valid corner case */
  46. if (xe == 63 && xs && xm == SP_HIDDEN_BIT)
  47. return -0x8000000000000000LL;
  48. /* Set invalid. We will only use overflow for floating
  49. point overflow */
  50. SETCX(IEEE754_INVALID_OPERATION);
  51. return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
  52. }
  53. /* oh gawd */
  54. if (xe > SP_MBITS) {
  55. xm <<= xe - SP_MBITS;
  56. } else if (xe < SP_MBITS) {
  57. u32 residue;
  58. int round;
  59. int sticky;
  60. int odd;
  61. if (xe < -1) {
  62. residue = xm;
  63. round = 0;
  64. sticky = residue != 0;
  65. xm = 0;
  66. } else {
  67. residue = xm << (32 - SP_MBITS + xe);
  68. round = (residue >> 31) != 0;
  69. sticky = (residue << 1) != 0;
  70. xm >>= SP_MBITS - xe;
  71. }
  72. odd = (xm & 0x1) != 0x0;
  73. switch (ieee754_csr.rm) {
  74. case IEEE754_RN:
  75. if (round && (sticky || odd))
  76. xm++;
  77. break;
  78. case IEEE754_RZ:
  79. break;
  80. case IEEE754_RU: /* toward +Infinity */
  81. if ((round || sticky) && !xs)
  82. xm++;
  83. break;
  84. case IEEE754_RD: /* toward -Infinity */
  85. if ((round || sticky) && xs)
  86. xm++;
  87. break;
  88. }
  89. if ((xm >> 63) != 0) {
  90. /* This can happen after rounding */
  91. SETCX(IEEE754_INVALID_OPERATION);
  92. return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
  93. }
  94. if (round || sticky)
  95. SETCX(IEEE754_INEXACT);
  96. }
  97. if (xs)
  98. return -xm;
  99. else
  100. return xm;
  101. }
  102. u64 ieee754sp_tulong(ieee754sp x)
  103. {
  104. ieee754sp hb = ieee754sp_1e63();
  105. /* what if x < 0 ?? */
  106. if (ieee754sp_lt(x, hb))
  107. return (u64) ieee754sp_tlong(x);
  108. return (u64) ieee754sp_tlong(ieee754sp_sub(x, hb)) |
  109. (1ULL << 63);
  110. }