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   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 int
  33 #define _FP_WS_TYPE             signed int
  34 #define _FP_I_TYPE              int
  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(_FP_WFRACBITS_S,R,X,Y,umul_ppmm)
  83 #define _FP_MUL_MEAT_D(R,X,Y)   _FP_MUL_MEAT_2_wide(_FP_WFRACBITS_D,R,X,Y,umul_ppmm)
  84
  85 #define _FP_DIV_MEAT_S(R,X,Y)   _FP_DIV_MEAT_1_udiv_norm(S,R,X,Y)
  86 #define _FP_DIV_MEAT_D(R,X,Y)   _FP_DIV_MEAT_2_udiv(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 << 1) - 1)
  92 #define _FP_NANFRAC_D           ((_FP_QNANBIT_D << 1) - 1), -1
  93 #define _FP_NANFRAC_Q           ((_FP_QNANBIT_Q << 1) - 1), -1, -1, -1
  94 #define _FP_NANSIGN_S           0
  95 #define _FP_NANSIGN_D           0
  96 #define _FP_NANSIGN_Q           0
  97
  98 #define _FP_KEEPNANFRACP 1
  99
 100 #ifdef FP_EX_BOOKE_E500_SPE
 101 #define FP_EX_INEXACT           (1 << 21)
 102 #define FP_EX_INVALID           (1 << 20)
 103 #define FP_EX_DIVZERO           (1 << 19)
 104 #define FP_EX_UNDERFLOW         (1 << 18)
 105 #define FP_EX_OVERFLOW          (1 << 17)
 106 #define FP_INHIBIT_RESULTS      0
 107
 108 #define __FPU_FPSCR     (current->thread.spefscr)
 109 #define __FPU_ENABLED_EXC               \
 110 ({                                      \
 111         (__FPU_FPSCR >> 2) & 0x1f;      \
 112 })
 113 #else
 114 /* Exception flags.  We use the bit positions of the appropriate bits
 115    in the FPSCR, which also correspond to the FE_* bits.  This makes
 116    everything easier ;-).  */
 117 #define FP_EX_INVALID         (1 << (31 - 2))
 118 #define FP_EX_INVALID_SNAN      EFLAG_VXSNAN
 119 #define FP_EX_INVALID_ISI       EFLAG_VXISI
 120 #define FP_EX_INVALID_IDI       EFLAG_VXIDI
 121 #define FP_EX_INVALID_ZDZ       EFLAG_VXZDZ
 122 #define FP_EX_INVALID_IMZ       EFLAG_VXIMZ
 123 #define FP_EX_OVERFLOW        (1 << (31 - 3))
 124 #define FP_EX_UNDERFLOW       (1 << (31 - 4))
 125 #define FP_EX_DIVZERO         (1 << (31 - 5))
 126 #define FP_EX_INEXACT         (1 << (31 - 6))
 127
 128 #define __FPU_FPSCR     (current->thread.fpscr.val)
 129
 130 /* We only actually write to the destination register
 131  * if exceptions signalled (if any) will not trap.
 132  */
 133 #define __FPU_ENABLED_EXC \
 134 ({                                              \
 135         (__FPU_FPSCR >> 3) & 0x1f;      \
 136 })
 137
 138 #endif
 139
 140 /*
 141  * If one NaN is signaling and the other is not,
 142  * we choose that one, otherwise we choose X.
 143  */
 144 #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP)                      \
 145   do {                                                          \
 146     if ((_FP_FRAC_HIGH_RAW_##fs(Y) & _FP_QNANBIT_##fs)          \
 147         && !(_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs))     \
 148       {                                                         \
 149         R##_s = X##_s;                                          \
 150         _FP_FRAC_COPY_##wc(R,X);                                \
 151       }                                                         \
 152     else                                                        \
 153       {                                                         \
 154         R##_s = Y##_s;                                          \
 155         _FP_FRAC_COPY_##wc(R,Y);                                \
 156       }                                                         \
 157     R##_c = FP_CLS_NAN;                                         \
 158   } while (0)
 159
 160
 161 #include <linux/kernel.h>
 162 #include <linux/sched.h>
 163
 164 #define __FPU_TRAP_P(bits) \
 165         ((__FPU_ENABLED_EXC & (bits)) != 0)
 166
 167 #define __FP_PACK_S(val,X)                      \
 168 ({  int __exc = _FP_PACK_CANONICAL(S,1,X);      \
 169     if(!__exc || !__FPU_TRAP_P(__exc))          \
 170         _FP_PACK_RAW_1_P(S,val,X);              \
 171     __exc;                                      \
 172 })
 173
 174 #define __FP_PACK_D(val,X)                      \
 175    do {                                                                 \
 176         _FP_PACK_CANONICAL(D, 2, X);                                    \
 177         if (!FP_CUR_EXCEPTIONS || !__FPU_TRAP_P(FP_CUR_EXCEPTIONS))     \
 178                 _FP_PACK_RAW_2_P(D, val, X);                            \
 179    } while (0)
 180
 181 #define __FP_PACK_DS(val,X)                                                     \
 182    do {                                                                         \
 183            FP_DECL_S(__X);                                                      \
 184            FP_CONV(S, D, 1, 2, __X, X);                                         \
 185            _FP_PACK_CANONICAL(S, 1, __X);                                       \
 186            if (!FP_CUR_EXCEPTIONS || !__FPU_TRAP_P(FP_CUR_EXCEPTIONS)) {        \
 187                    _FP_UNPACK_CANONICAL(S, 1, __X);                             \
 188                    FP_CONV(D, S, 2, 1, X, __X);                                 \
 189                    _FP_PACK_CANONICAL(D, 2, X);                                 \
 190                    if (!FP_CUR_EXCEPTIONS || !__FPU_TRAP_P(FP_CUR_EXCEPTIONS))  \
 191                    _FP_PACK_RAW_2_P(D, val, X);                                 \
 192            }                                                                    \
 193    } while (0)
 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))