arch/powerpc/math-emu/sfp-machine.h

   1 /* Machine-dependent software floating-point definitions.  PPC version.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If
  17    not, write to the Free Software Foundation, Inc.,
  18    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19
  20    Actually, this is a PPC (32bit) version, written based on the
  21    i386, sparc, and sparc64 versions, by me,
  22    Peter Maydell (pmaydell@chiark.greenend.org.uk).
  23    Comments are by and large also mine, although they may be inaccurate.
  24
  25    In picking out asm fragments I've gone with the lowest common
  26    denominator, which also happens to be the hardware I have :->
  27    That is, a SPARC without hardware multiply and divide.
  28  */
  29
  30 /* basic word size definitions */
  31 #define _FP_W_TYPE_SIZE         32
  32 #define _FP_W_TYPE              unsigned long
  33 #define _FP_WS_TYPE             signed long
  34 #define _FP_I_TYPE              long
  35
  36 #define __ll_B                  ((UWtype) 1 << (W_TYPE_SIZE / 2))
  37 #define __ll_lowpart(t)         ((UWtype) (t) & (__ll_B - 1))
  38 #define __ll_highpart(t)        ((UWtype) (t) >> (W_TYPE_SIZE / 2))
  39
  40 /* You can optionally code some things like addition in asm. For
  41  * example, i386 defines __FP_FRAC_ADD_2 as asm. If you don't
  42  * then you get a fragment of C code [if you change an #ifdef 0
  43  * in op-2.h] or a call to add_ssaaaa (see below).
  44  * Good places to look for asm fragments to use are gcc and glibc.
  45  * gcc's longlong.h is useful.
  46  */
  47
  48 /* We need to know how to multiply and divide. If the host word size
  49  * is >= 2*fracbits you can use FP_MUL_MEAT_n_imm(t,R,X,Y) which
  50  * codes the multiply with whatever gcc does to 'a * b'.
  51  * _FP_MUL_MEAT_n_wide(t,R,X,Y,f) is used when you have an asm
  52  * function that can multiply two 1W values and get a 2W result.
  53  * Otherwise you're stuck with _FP_MUL_MEAT_n_hard(t,R,X,Y) which
  54  * does bitshifting to avoid overflow.
  55  * For division there is FP_DIV_MEAT_n_imm(t,R,X,Y,f) for word size
  56  * >= 2*fracbits, where f is either _FP_DIV_HELP_imm or
  57  * _FP_DIV_HELP_ldiv (see op-1.h).
  58  * _FP_DIV_MEAT_udiv() is if you have asm to do 2W/1W => (1W, 1W).
  59  * [GCC and glibc have longlong.h which has the asm macro udiv_qrnnd
  60  * to do this.]
  61  * In general, 'n' is the number of words required to hold the type,
  62  * and 't' is either S, D or Q for single/double/quad.
  63  *           -- PMM
  64  */
  65 /* Example: SPARC64:
  66  * #define _FP_MUL_MEAT_S(R,X,Y)        _FP_MUL_MEAT_1_imm(S,R,X,Y)
  67  * #define _FP_MUL_MEAT_D(R,X,Y)        _FP_MUL_MEAT_1_wide(D,R,X,Y,umul_ppmm)
  68  * #define _FP_MUL_MEAT_Q(R,X,Y)        _FP_MUL_MEAT_2_wide(Q,R,X,Y,umul_ppmm)
  69  *
  70  * #define _FP_DIV_MEAT_S(R,X,Y)        _FP_DIV_MEAT_1_imm(S,R,X,Y,_FP_DIV_HELP_imm)
  71  * #define _FP_DIV_MEAT_D(R,X,Y)        _FP_DIV_MEAT_1_udiv(D,R,X,Y)
  72  * #define _FP_DIV_MEAT_Q(R,X,Y)        _FP_DIV_MEAT_2_udiv_64(Q,R,X,Y)
  73  *
  74  * Example: i386:
  75  * #define _FP_MUL_MEAT_S(R,X,Y)   _FP_MUL_MEAT_1_wide(S,R,X,Y,_i386_mul_32_64)
  76  * #define _FP_MUL_MEAT_D(R,X,Y)   _FP_MUL_MEAT_2_wide(D,R,X,Y,_i386_mul_32_64)
  77  *
  78  * #define _FP_DIV_MEAT_S(R,X,Y)   _FP_DIV_MEAT_1_udiv(S,R,X,Y,_i386_div_64_32)
  79  * #define _FP_DIV_MEAT_D(R,X,Y)   _FP_DIV_MEAT_2_udiv_64(D,R,X,Y)
  80  */
  81
  82 #define _FP_MUL_MEAT_S(R,X,Y)   _FP_MUL_MEAT_1_wide(S,R,X,Y,umul_ppmm)
  83 #define _FP_MUL_MEAT_D(R,X,Y)   _FP_MUL_MEAT_2_wide(D,R,X,Y,umul_ppmm)
  84
  85 #define _FP_DIV_MEAT_S(R,X,Y)   _FP_DIV_MEAT_1_udiv(S,R,X,Y)
  86 #define _FP_DIV_MEAT_D(R,X,Y)   _FP_DIV_MEAT_2_udiv_64(D,R,X,Y)
  87
  88 /* These macros define what NaN looks like. They're supposed to expand to
  89  * a comma-separated set of 32bit unsigned ints that encode NaN.
  90  */
  91 #define _FP_NANFRAC_S           _FP_QNANBIT_S
  92 #define _FP_NANFRAC_D           _FP_QNANBIT_D, 0
  93 #define _FP_NANFRAC_Q           _FP_QNANBIT_Q, 0, 0, 0
  94
  95 #define _FP_KEEPNANFRACP 1
  96
  97 /* This macro appears to be called when both X and Y are NaNs, and
  98  * has to choose one and copy it to R. i386 goes for the larger of the
  99  * two, sparc64 just picks Y. I don't understand this at all so I'll
 100  * go with sparc64 because it's shorter :->   -- PMM
 101  */
 102 #define _FP_CHOOSENAN(fs, wc, R, X, Y)                  \
 103   do {                                                  \
 104     R##_s = Y##_s;                                      \
 105     _FP_FRAC_COPY_##wc(R,Y);                            \
 106     R##_c = FP_CLS_NAN;                                 \
 107   } while (0)
 108
 109
 110 extern void fp_unpack_d(long *, unsigned long *, unsigned long *,
 111                         long *, long *, void *);
 112 extern int  fp_pack_d(void *, long, unsigned long, unsigned long, long, long);
 113 extern int  fp_pack_ds(void *, long, unsigned long, unsigned long, long, long);
 114
 115 #define __FP_UNPACK_RAW_1(fs, X, val)                   \
 116   do {                                                  \
 117     union _FP_UNION_##fs *_flo =                        \
 118         (union _FP_UNION_##fs *)val;                    \
 119                                                         \
 120     X##_f = _flo->bits.frac;                            \
 121     X##_e = _flo->bits.exp;                             \
 122     X##_s = _flo->bits.sign;                            \
 123   } while (0)
 124
 125 #define __FP_UNPACK_RAW_2(fs, X, val)                   \
 126   do {                                                  \
 127     union _FP_UNION_##fs *_flo =                        \
 128         (union _FP_UNION_##fs *)val;                    \
 129                                                         \
 130     X##_f0 = _flo->bits.frac0;                          \
 131     X##_f1 = _flo->bits.frac1;                          \
 132     X##_e  = _flo->bits.exp;                            \
 133     X##_s  = _flo->bits.sign;                           \
 134   } while (0)
 135
 136 #define __FP_UNPACK_S(X,val)            \
 137   do {                                  \
 138     __FP_UNPACK_RAW_1(S,X,val);         \
 139     _FP_UNPACK_CANONICAL(S,1,X);        \
 140   } while (0)
 141
 142 #define __FP_UNPACK_D(X,val)            \
 143         fp_unpack_d(&X##_s, &X##_f1, &X##_f0, &X##_e, &X##_c, val)
 144
 145 #define __FP_PACK_RAW_1(fs, val, X)                     \
 146   do {                                                  \
 147     union _FP_UNION_##fs *_flo =                        \
 148         (union _FP_UNION_##fs *)val;                    \
 149                                                         \
 150     _flo->bits.frac = X##_f;                            \
 151     _flo->bits.exp  = X##_e;                            \
 152     _flo->bits.sign = X##_s;                            \
 153   } while (0)
 154
 155 #define __FP_PACK_RAW_2(fs, val, X)                     \
 156   do {                                                  \
 157     union _FP_UNION_##fs *_flo =                        \
 158         (union _FP_UNION_##fs *)val;                    \
 159                                                         \
 160     _flo->bits.frac0 = X##_f0;                          \
 161     _flo->bits.frac1 = X##_f1;                          \
 162     _flo->bits.exp   = X##_e;                           \
 163     _flo->bits.sign  = X##_s;                           \
 164   } while (0)
 165
 166 #include <linux/kernel.h>
 167 #include <linux/sched.h>
 168
 169 #define __FPU_FPSCR     (current->thread.fpscr.val)
 170
 171 /* We only actually write to the destination register
 172  * if exceptions signalled (if any) will not trap.
 173  */
 174 #define __FPU_ENABLED_EXC \
 175 ({                                              \
 176         (__FPU_FPSCR >> 3) & 0x1f;      \
 177 })
 178
 179 #define __FPU_TRAP_P(bits) \
 180         ((__FPU_ENABLED_EXC & (bits)) != 0)
 181
 182 #define __FP_PACK_S(val,X)                      \
 183 ({  int __exc = _FP_PACK_CANONICAL(S,1,X);      \
 184     if(!__exc || !__FPU_TRAP_P(__exc))          \
 185         __FP_PACK_RAW_1(S,val,X);               \
 186     __exc;                                      \
 187 })
 188
 189 #define __FP_PACK_D(val,X)                      \
 190         fp_pack_d(val, X##_s, X##_f1, X##_f0, X##_e, X##_c)
 191
 192 #define __FP_PACK_DS(val,X)                     \
 193         fp_pack_ds(val, X##_s, X##_f1, X##_f0, X##_e, X##_c)
 194
 195 /* Obtain the current rounding mode. */
 196 #define FP_ROUNDMODE                    \
 197 ({                                      \
 198         __FPU_FPSCR & 0x3;              \
 199 })
 200
 201 /* the asm fragments go here: all these are taken from glibc-2.0.5's
 202  * stdlib/longlong.h
 203  */
 204
 205 #include <linux/types.h>
 206 #include <asm/byteorder.h>
 207
 208 /* add_ssaaaa is used in op-2.h and should be equivalent to
 209  * #define add_ssaaaa(sh,sl,ah,al,bh,bl) (sh = ah+bh+ (( sl = al+bl) < al))
 210  * add_ssaaaa(high_sum, low_sum, high_addend_1, low_addend_1,
 211  * high_addend_2, low_addend_2) adds two UWtype integers, composed by
 212  * HIGH_ADDEND_1 and LOW_ADDEND_1, and HIGH_ADDEND_2 and LOW_ADDEND_2
 213  * respectively.  The result is placed in HIGH_SUM and LOW_SUM.  Overflow
 214  * (i.e. carry out) is not stored anywhere, and is lost.
 215  */
 216 #define add_ssaaaa(sh, sl, ah, al, bh, bl)                              \
 217   do {                                                                  \
 218     if (__builtin_constant_p (bh) && (bh) == 0)                         \
 219       __asm__ ("{a%I4|add%I4c} %1,%3,%4\n\t{aze|addze} %0,%2"           \
 220              : "=r" ((USItype)(sh)),                                    \
 221                "=&r" ((USItype)(sl))                                    \
 222              : "%r" ((USItype)(ah)),                                    \
 223                "%r" ((USItype)(al)),                                    \
 224                "rI" ((USItype)(bl)));                                   \
 225     else if (__builtin_constant_p (bh) && (bh) ==~(USItype) 0)          \
 226       __asm__ ("{a%I4|add%I4c} %1,%3,%4\n\t{ame|addme} %0,%2"           \
 227              : "=r" ((USItype)(sh)),                                    \
 228                "=&r" ((USItype)(sl))                                    \
 229              : "%r" ((USItype)(ah)),                                    \
 230                "%r" ((USItype)(al)),                                    \
 231                "rI" ((USItype)(bl)));                                   \
 232     else                                                                \
 233       __asm__ ("{a%I5|add%I5c} %1,%4,%5\n\t{ae|adde} %0,%2,%3"          \
 234              : "=r" ((USItype)(sh)),                                    \
 235                "=&r" ((USItype)(sl))                                    \
 236              : "%r" ((USItype)(ah)),                                    \
 237                "r" ((USItype)(bh)),                                     \
 238                "%r" ((USItype)(al)),                                    \
 239                "rI" ((USItype)(bl)));                                   \
 240   } while (0)
 241
 242 /* sub_ddmmss is used in op-2.h and udivmodti4.c and should be equivalent to
 243  * #define sub_ddmmss(sh, sl, ah, al, bh, bl) (sh = ah-bh - ((sl = al-bl) > al))
 244  * sub_ddmmss(high_difference, low_difference, high_minuend, low_minuend,
 245  * high_subtrahend, low_subtrahend) subtracts two two-word UWtype integers,
 246  * composed by HIGH_MINUEND_1 and LOW_MINUEND_1, and HIGH_SUBTRAHEND_2 and
 247  * LOW_SUBTRAHEND_2 respectively.  The result is placed in HIGH_DIFFERENCE
 248  * and LOW_DIFFERENCE.  Overflow (i.e. carry out) is not stored anywhere,
 249  * and is lost.
 250  */
 251 #define sub_ddmmss(sh, sl, ah, al, bh, bl)                              \
 252   do {                                                                  \
 253     if (__builtin_constant_p (ah) && (ah) == 0)                         \
 254       __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{sfze|subfze} %0,%2"       \
 255                : "=r" ((USItype)(sh)),                                  \
 256                  "=&r" ((USItype)(sl))                                  \
 257                : "r" ((USItype)(bh)),                                   \
 258                  "rI" ((USItype)(al)),                                  \
 259                  "r" ((USItype)(bl)));                                  \
 260     else if (__builtin_constant_p (ah) && (ah) ==~(USItype) 0)          \
 261       __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{sfme|subfme} %0,%2"       \
 262                : "=r" ((USItype)(sh)),                                  \
 263                  "=&r" ((USItype)(sl))                                  \
 264                : "r" ((USItype)(bh)),                                   \
 265                  "rI" ((USItype)(al)),                                  \
 266                  "r" ((USItype)(bl)));                                  \
 267     else if (__builtin_constant_p (bh) && (bh) == 0)                    \
 268       __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{ame|addme} %0,%2"         \
 269                : "=r" ((USItype)(sh)),                                  \
 270                  "=&r" ((USItype)(sl))                                  \
 271                : "r" ((USItype)(ah)),                                   \
 272                  "rI" ((USItype)(al)),                                  \
 273                  "r" ((USItype)(bl)));                                  \
 274     else if (__builtin_constant_p (bh) && (bh) ==~(USItype) 0)          \
 275       __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{aze|addze} %0,%2"         \
 276                : "=r" ((USItype)(sh)),                                  \
 277                  "=&r" ((USItype)(sl))                                  \
 278                : "r" ((USItype)(ah)),                                   \
 279                  "rI" ((USItype)(al)),                                  \
 280                  "r" ((USItype)(bl)));                                  \
 281     else                                                                \
 282       __asm__ ("{sf%I4|subf%I4c} %1,%5,%4\n\t{sfe|subfe} %0,%3,%2"      \
 283                : "=r" ((USItype)(sh)),                                  \
 284                  "=&r" ((USItype)(sl))                                  \
 285                : "r" ((USItype)(ah)),                                   \
 286                  "r" ((USItype)(bh)),                                   \
 287                  "rI" ((USItype)(al)),                                  \
 288                  "r" ((USItype)(bl)));                                  \
 289   } while (0)
 290
 291 /* asm fragments for mul and div */
 292
 293 /* umul_ppmm(high_prod, low_prod, multipler, multiplicand) multiplies two
 294  * UWtype integers MULTIPLER and MULTIPLICAND, and generates a two UWtype
 295  * word product in HIGH_PROD and LOW_PROD.
 296  */
 297 #define umul_ppmm(ph, pl, m0, m1)                                       \
 298   do {                                                                  \
 299     USItype __m0 = (m0), __m1 = (m1);                                   \
 300     __asm__ ("mulhwu %0,%1,%2"                                          \
 301              : "=r" ((USItype)(ph))                                     \
 302              : "%r" (__m0),                                             \
 303                "r" (__m1));                                             \
 304     (pl) = __m0 * __m1;                                                 \
 305   } while (0)
 306
 307 /* udiv_qrnnd(quotient, remainder, high_numerator, low_numerator,
 308  * denominator) divides a UDWtype, composed by the UWtype integers
 309  * HIGH_NUMERATOR and LOW_NUMERATOR, by DENOMINATOR and places the quotient
 310  * in QUOTIENT and the remainder in REMAINDER.  HIGH_NUMERATOR must be less
 311  * than DENOMINATOR for correct operation.  If, in addition, the most
 312  * significant bit of DENOMINATOR must be 1, then the pre-processor symbol
 313  * UDIV_NEEDS_NORMALIZATION is defined to 1.
 314  */
 315 #define udiv_qrnnd(q, r, n1, n0, d)                                     \
 316   do {                                                                  \
 317     UWtype __d1, __d0, __q1, __q0, __r1, __r0, __m;                     \
 318     __d1 = __ll_highpart (d);                                           \
 319     __d0 = __ll_lowpart (d);                                            \
 320                                                                         \
 321     __r1 = (n1) % __d1;                                                 \
 322     __q1 = (n1) / __d1;                                                 \
 323     __m = (UWtype) __q1 * __d0;                                         \
 324     __r1 = __r1 * __ll_B | __ll_highpart (n0);                          \
 325     if (__r1 < __m)                                                     \
 326       {                                                                 \
 327         __q1--, __r1 += (d);                                            \
 328         if (__r1 >= (d)) /* we didn't get carry when adding to __r1 */  \
 329           if (__r1 < __m)                                               \
 330             __q1--, __r1 += (d);                                        \
 331       }                                                                 \
 332     __r1 -= __m;                                                        \
 333                                                                         \
 334     __r0 = __r1 % __d1;                                                 \
 335     __q0 = __r1 / __d1;                                                 \
 336     __m = (UWtype) __q0 * __d0;                                         \
 337     __r0 = __r0 * __ll_B | __ll_lowpart (n0);                           \
 338     if (__r0 < __m)                                                     \
 339       {                                                                 \
 340         __q0--, __r0 += (d);                                            \
 341         if (__r0 >= (d))                                                \
 342           if (__r0 < __m)                                               \
 343             __q0--, __r0 += (d);                                        \
 344       }                                                                 \
 345     __r0 -= __m;                                                        \
 346                                                                         \
 347     (q) = (UWtype) __q1 * __ll_B | __q0;                                \
 348     (r) = __r0;                                                         \
 349   } while (0)
 350
 351 #define UDIV_NEEDS_NORMALIZATION 1
 352
 353 #define abort()                                                         \
 354         return 0
 355
 356 #ifdef __BIG_ENDIAN
 357 #define __BYTE_ORDER __BIG_ENDIAN
 358 #else
 359 #define __BYTE_ORDER __LITTLE_ENDIAN
 360 #endif
 361
 362 /* Exception flags. */
 363 #define EFLAG_INVALID           (1 << (31 - 2))
 364 #define EFLAG_OVERFLOW          (1 << (31 - 3))
 365 #define EFLAG_UNDERFLOW         (1 << (31 - 4))
 366 #define EFLAG_DIVZERO           (1 << (31 - 5))
 367 #define EFLAG_INEXACT           (1 << (31 - 6))
 368
 369 #define EFLAG_VXSNAN            (1 << (31 - 7))
 370 #define EFLAG_VXISI             (1 << (31 - 8))
 371 #define EFLAG_VXIDI             (1 << (31 - 9))
 372 #define EFLAG_VXZDZ             (1 << (31 - 10))
 373 #define EFLAG_VXIMZ             (1 << (31 - 11))
 374 #define EFLAG_VXVC              (1 << (31 - 12))
 375 #define EFLAG_VXSOFT            (1 << (31 - 21))
 376 #define EFLAG_VXSQRT            (1 << (31 - 22))
 377 #define EFLAG_VXCVI             (1 << (31 - 23))