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