| 1 | /* Software floating-point emulation. |
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| 2 | Basic one-word fraction declaration and manipulation. |
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| 3 | Copyright (C) 1997,1998,1999 Free Software Foundation, Inc. |
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| 4 | This file is part of the GNU C Library. |
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| 5 | Contributed by Richard Henderson (rth@cygnus.com), |
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| 6 | Jakub Jelinek (jj@ultra.linux.cz), |
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| 7 | David S. Miller (davem@redhat.com) and |
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| 8 | Peter Maydell (pmaydell@chiark.greenend.org.uk). |
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| 9 | |
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| 10 | The GNU C Library is free software; you can redistribute it and/or |
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| 11 | modify it under the terms of the GNU Library General Public License as |
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| 12 | published by the Free Software Foundation; either version 2 of the |
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| 13 | License, or (at your option) any later version. |
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| 14 | |
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| 15 | The GNU C Library is distributed in the hope that it will be useful, |
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| 16 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 18 | Library General Public License for more details. |
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| 19 | |
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| 20 | You should have received a copy of the GNU Library General Public |
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| 21 | License along with the GNU C Library; see the file COPYING.LIB. If |
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| 22 | not, write to the Free Software Foundation, Inc., |
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| 23 | 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
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| 24 | |
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| 25 | #ifndef __MATH_EMU_OP_1_H__ |
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| 26 | #define __MATH_EMU_OP_1_H__ |
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| 27 | |
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| 28 | #define _FP_FRAC_DECL_1(X) _FP_W_TYPE X##_f=0 |
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| 29 | #define _FP_FRAC_COPY_1(D,S) (D##_f = S##_f) |
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| 30 | #define _FP_FRAC_SET_1(X,I) (X##_f = I) |
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| 31 | #define _FP_FRAC_HIGH_1(X) (X##_f) |
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| 32 | #define _FP_FRAC_LOW_1(X) (X##_f) |
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| 33 | #define _FP_FRAC_WORD_1(X,w) (X##_f) |
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| 34 | |
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| 35 | #define _FP_FRAC_ADDI_1(X,I) (X##_f += I) |
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| 36 | #define _FP_FRAC_SLL_1(X,N) \ |
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| 37 | do { \ |
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| 38 | if (__builtin_constant_p(N) && (N) == 1) \ |
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| 39 | X##_f += X##_f; \ |
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| 40 | else \ |
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| 41 | X##_f <<= (N); \ |
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| 42 | } while (0) |
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| 43 | #define _FP_FRAC_SRL_1(X,N) (X##_f >>= N) |
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| 44 | |
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| 45 | /* Right shift with sticky-lsb. */ |
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| 46 | #define _FP_FRAC_SRS_1(X,N,sz) __FP_FRAC_SRS_1(X##_f, N, sz) |
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| 47 | |
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| 48 | #define __FP_FRAC_SRS_1(X,N,sz) \ |
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| 49 | (X = (X >> (N) | (__builtin_constant_p(N) && (N) == 1 \ |
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| 50 | ? X & 1 : (X << (_FP_W_TYPE_SIZE - (N))) != 0))) |
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| 51 | |
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| 52 | #define _FP_FRAC_ADD_1(R,X,Y) (R##_f = X##_f + Y##_f) |
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| 53 | #define _FP_FRAC_SUB_1(R,X,Y) (R##_f = X##_f - Y##_f) |
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| 54 | #define _FP_FRAC_DEC_1(X,Y) (X##_f -= Y##_f) |
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| 55 | #define _FP_FRAC_CLZ_1(z, X) __FP_CLZ(z, X##_f) |
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| 56 | |
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| 57 | /* Predicates */ |
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| 58 | #define _FP_FRAC_NEGP_1(X) ((_FP_WS_TYPE)X##_f < 0) |
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| 59 | #define _FP_FRAC_ZEROP_1(X) (X##_f == 0) |
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| 60 | #define _FP_FRAC_OVERP_1(fs,X) (X##_f & _FP_OVERFLOW_##fs) |
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| 61 | #define _FP_FRAC_CLEAR_OVERP_1(fs,X) (X##_f &= ~_FP_OVERFLOW_##fs) |
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| 62 | #define _FP_FRAC_EQ_1(X, Y) (X##_f == Y##_f) |
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| 63 | #define _FP_FRAC_GE_1(X, Y) (X##_f >= Y##_f) |
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| 64 | #define _FP_FRAC_GT_1(X, Y) (X##_f > Y##_f) |
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| 65 | |
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| 66 | #define _FP_ZEROFRAC_1 0 |
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| 67 | #define _FP_MINFRAC_1 1 |
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| 68 | #define _FP_MAXFRAC_1 (~(_FP_WS_TYPE)0) |
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| 69 | |
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| 70 | /* |
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| 71 | * Unpack the raw bits of a native fp value. Do not classify or |
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| 72 | * normalize the data. |
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| 73 | */ |
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| 74 | |
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| 75 | #define _FP_UNPACK_RAW_1(fs, X, val) \ |
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| 76 | do { \ |
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| 77 | union _FP_UNION_##fs _flo; _flo.flt = (val); \ |
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| 78 | \ |
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| 79 | X##_f = _flo.bits.frac; \ |
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| 80 | X##_e = _flo.bits.exp; \ |
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| 81 | X##_s = _flo.bits.sign; \ |
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| 82 | } while (0) |
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| 83 | |
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| 84 | #define _FP_UNPACK_RAW_1_P(fs, X, val) \ |
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| 85 | do { \ |
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| 86 | union _FP_UNION_##fs *_flo = \ |
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| 87 | (union _FP_UNION_##fs *)(val); \ |
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| 88 | \ |
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| 89 | X##_f = _flo->bits.frac; \ |
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| 90 | X##_e = _flo->bits.exp; \ |
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| 91 | X##_s = _flo->bits.sign; \ |
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| 92 | } while (0) |
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| 93 | |
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| 94 | /* |
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| 95 | * Repack the raw bits of a native fp value. |
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| 96 | */ |
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| 97 | |
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| 98 | #define _FP_PACK_RAW_1(fs, val, X) \ |
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| 99 | do { \ |
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| 100 | union _FP_UNION_##fs _flo; \ |
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| 101 | \ |
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| 102 | _flo.bits.frac = X##_f; \ |
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| 103 | _flo.bits.exp = X##_e; \ |
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| 104 | _flo.bits.sign = X##_s; \ |
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| 105 | \ |
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| 106 | (val) = _flo.flt; \ |
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| 107 | } while (0) |
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| 108 | |
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| 109 | #define _FP_PACK_RAW_1_P(fs, val, X) \ |
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| 110 | do { \ |
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| 111 | union _FP_UNION_##fs *_flo = \ |
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| 112 | (union _FP_UNION_##fs *)(val); \ |
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| 113 | \ |
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| 114 | _flo->bits.frac = X##_f; \ |
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| 115 | _flo->bits.exp = X##_e; \ |
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| 116 | _flo->bits.sign = X##_s; \ |
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| 117 | } while (0) |
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| 118 | |
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| 119 | |
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| 120 | /* |
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| 121 | * Multiplication algorithms: |
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| 122 | */ |
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| 123 | |
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| 124 | /* Basic. Assuming the host word size is >= 2*FRACBITS, we can do the |
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| 125 | multiplication immediately. */ |
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| 126 | |
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| 127 | #define _FP_MUL_MEAT_1_imm(wfracbits, R, X, Y) \ |
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| 128 | do { \ |
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| 129 | R##_f = X##_f * Y##_f; \ |
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| 130 | /* Normalize since we know where the msb of the multiplicands \ |
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| 131 | were (bit B), we know that the msb of the of the product is \ |
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| 132 | at either 2B or 2B-1. */ \ |
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| 133 | _FP_FRAC_SRS_1(R, wfracbits-1, 2*wfracbits); \ |
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| 134 | } while (0) |
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| 135 | |
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| 136 | /* Given a 1W * 1W => 2W primitive, do the extended multiplication. */ |
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| 137 | |
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| 138 | #define _FP_MUL_MEAT_1_wide(wfracbits, R, X, Y, doit) \ |
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| 139 | do { \ |
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| 140 | _FP_W_TYPE _Z_f0, _Z_f1; \ |
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| 141 | doit(_Z_f1, _Z_f0, X##_f, Y##_f); \ |
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| 142 | /* Normalize since we know where the msb of the multiplicands \ |
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| 143 | were (bit B), we know that the msb of the of the product is \ |
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| 144 | at either 2B or 2B-1. */ \ |
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| 145 | _FP_FRAC_SRS_2(_Z, wfracbits-1, 2*wfracbits); \ |
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| 146 | R##_f = _Z_f0; \ |
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| 147 | } while (0) |
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| 148 | |
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| 149 | /* Finally, a simple widening multiply algorithm. What fun! */ |
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| 150 | |
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| 151 | #define _FP_MUL_MEAT_1_hard(wfracbits, R, X, Y) \ |
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| 152 | do { \ |
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| 153 | _FP_W_TYPE _xh, _xl, _yh, _yl, _z_f0, _z_f1, _a_f0, _a_f1; \ |
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| 154 | \ |
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| 155 | /* split the words in half */ \ |
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| 156 | _xh = X##_f >> (_FP_W_TYPE_SIZE/2); \ |
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| 157 | _xl = X##_f & (((_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2)) - 1); \ |
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| 158 | _yh = Y##_f >> (_FP_W_TYPE_SIZE/2); \ |
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| 159 | _yl = Y##_f & (((_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2)) - 1); \ |
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| 160 | \ |
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| 161 | /* multiply the pieces */ \ |
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| 162 | _z_f0 = _xl * _yl; \ |
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| 163 | _a_f0 = _xh * _yl; \ |
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| 164 | _a_f1 = _xl * _yh; \ |
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| 165 | _z_f1 = _xh * _yh; \ |
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| 166 | \ |
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| 167 | /* reassemble into two full words */ \ |
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| 168 | if ((_a_f0 += _a_f1) < _a_f1) \ |
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| 169 | _z_f1 += (_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2); \ |
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| 170 | _a_f1 = _a_f0 >> (_FP_W_TYPE_SIZE/2); \ |
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| 171 | _a_f0 = _a_f0 << (_FP_W_TYPE_SIZE/2); \ |
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| 172 | _FP_FRAC_ADD_2(_z, _z, _a); \ |
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| 173 | \ |
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| 174 | /* normalize */ \ |
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| 175 | _FP_FRAC_SRS_2(_z, wfracbits - 1, 2*wfracbits); \ |
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| 176 | R##_f = _z_f0; \ |
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| 177 | } while (0) |
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| 178 | |
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| 179 | |
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| 180 | /* |
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| 181 | * Division algorithms: |
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| 182 | */ |
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| 183 | |
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| 184 | /* Basic. Assuming the host word size is >= 2*FRACBITS, we can do the |
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| 185 | division immediately. Give this macro either _FP_DIV_HELP_imm for |
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| 186 | C primitives or _FP_DIV_HELP_ldiv for the ISO function. Which you |
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| 187 | choose will depend on what the compiler does with divrem4. */ |
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| 188 | |
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| 189 | #define _FP_DIV_MEAT_1_imm(fs, R, X, Y, doit) \ |
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| 190 | do { \ |
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| 191 | _FP_W_TYPE _q, _r; \ |
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| 192 | X##_f <<= (X##_f < Y##_f \ |
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| 193 | ? R##_e--, _FP_WFRACBITS_##fs \ |
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| 194 | : _FP_WFRACBITS_##fs - 1); \ |
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| 195 | doit(_q, _r, X##_f, Y##_f); \ |
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| 196 | R##_f = _q | (_r != 0); \ |
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| 197 | } while (0) |
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| 198 | |
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| 199 | /* GCC's longlong.h defines a 2W / 1W => (1W,1W) primitive udiv_qrnnd |
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| 200 | that may be useful in this situation. This first is for a primitive |
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| 201 | that requires normalization, the second for one that does not. Look |
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| 202 | for UDIV_NEEDS_NORMALIZATION to tell which your machine needs. */ |
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| 203 | |
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| 204 | #define _FP_DIV_MEAT_1_udiv_norm(fs, R, X, Y) \ |
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| 205 | do { \ |
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| 206 | _FP_W_TYPE _nh, _nl, _q, _r, _y; \ |
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| 207 | \ |
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| 208 | /* Normalize Y -- i.e. make the most significant bit set. */ \ |
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| 209 | _y = Y##_f << _FP_WFRACXBITS_##fs; \ |
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| 210 | \ |
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| 211 | /* Shift X op correspondingly high, that is, up one full word. */ \ |
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| 212 | if (X##_f < Y##_f) \ |
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| 213 | { \ |
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| 214 | R##_e--; \ |
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| 215 | _nl = 0; \ |
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| 216 | _nh = X##_f; \ |
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| 217 | } \ |
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| 218 | else \ |
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| 219 | { \ |
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| 220 | _nl = X##_f << (_FP_W_TYPE_SIZE - 1); \ |
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| 221 | _nh = X##_f >> 1; \ |
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| 222 | } \ |
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| 223 | \ |
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| 224 | udiv_qrnnd(_q, _r, _nh, _nl, _y); \ |
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| 225 | R##_f = _q | (_r != 0); \ |
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| 226 | } while (0) |
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| 227 | |
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| 228 | #define _FP_DIV_MEAT_1_udiv(fs, R, X, Y) \ |
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| 229 | do { \ |
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| 230 | _FP_W_TYPE _nh, _nl, _q, _r; \ |
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| 231 | if (X##_f < Y##_f) \ |
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| 232 | { \ |
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| 233 | R##_e--; \ |
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| 234 | _nl = X##_f << _FP_WFRACBITS_##fs; \ |
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| 235 | _nh = X##_f >> _FP_WFRACXBITS_##fs; \ |
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| 236 | } \ |
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| 237 | else \ |
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| 238 | { \ |
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| 239 | _nl = X##_f << (_FP_WFRACBITS_##fs - 1); \ |
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| 240 | _nh = X##_f >> (_FP_WFRACXBITS_##fs + 1); \ |
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| 241 | } \ |
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| 242 | udiv_qrnnd(_q, _r, _nh, _nl, Y##_f); \ |
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| 243 | R##_f = _q | (_r != 0); \ |
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| 244 | } while (0) |
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| 245 | |
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| 246 | |
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| 247 | /* |
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| 248 | * Square root algorithms: |
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| 249 | * We have just one right now, maybe Newton approximation |
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| 250 | * should be added for those machines where division is fast. |
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| 251 | */ |
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| 252 | |
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| 253 | #define _FP_SQRT_MEAT_1(R, S, T, X, q) \ |
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| 254 | do { \ |
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| 255 | while (q != _FP_WORK_ROUND) \ |
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| 256 | { \ |
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| 257 | T##_f = S##_f + q; \ |
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| 258 | if (T##_f <= X##_f) \ |
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| 259 | { \ |
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| 260 | S##_f = T##_f + q; \ |
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| 261 | X##_f -= T##_f; \ |
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| 262 | R##_f += q; \ |
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| 263 | } \ |
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| 264 | _FP_FRAC_SLL_1(X, 1); \ |
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| 265 | q >>= 1; \ |
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| 266 | } \ |
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| 267 | if (X##_f) \ |
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| 268 | { \ |
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| 269 | if (S##_f < X##_f) \ |
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| 270 | R##_f |= _FP_WORK_ROUND; \ |
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| 271 | R##_f |= _FP_WORK_STICKY; \ |
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| 272 | } \ |
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| 273 | } while (0) |
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| 274 | |
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| 275 | /* |
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| 276 | * Assembly/disassembly for converting to/from integral types. |
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| 277 | * No shifting or overflow handled here. |
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| 278 | */ |
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| 279 | |
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| 280 | #define _FP_FRAC_ASSEMBLE_1(r, X, rsize) (r = X##_f) |
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| 281 | #define _FP_FRAC_DISASSEMBLE_1(X, r, rsize) (X##_f = r) |
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| 282 | |
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| 283 | |
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| 284 | /* |
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| 285 | * Convert FP values between word sizes |
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| 286 | */ |
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| 287 | |
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| 288 | #define _FP_FRAC_CONV_1_1(dfs, sfs, D, S) \ |
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| 289 | do { \ |
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| 290 | D##_f = S##_f; \ |
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| 291 | if (_FP_WFRACBITS_##sfs > _FP_WFRACBITS_##dfs) \ |
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| 292 | { \ |
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| 293 | if (S##_c != FP_CLS_NAN) \ |
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| 294 | _FP_FRAC_SRS_1(D, (_FP_WFRACBITS_##sfs-_FP_WFRACBITS_##dfs), \ |
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| 295 | _FP_WFRACBITS_##sfs); \ |
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| 296 | else \ |
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| 297 | _FP_FRAC_SRL_1(D, (_FP_WFRACBITS_##sfs-_FP_WFRACBITS_##dfs)); \ |
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| 298 | } \ |
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| 299 | else \ |
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| 300 | D##_f <<= _FP_WFRACBITS_##dfs - _FP_WFRACBITS_##sfs; \ |
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| 301 | } while (0) |
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| 302 | |
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| 303 | #endif /* __MATH_EMU_OP_1_H__ */ |
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| 304 | |
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