arch/powerpc/include/asm/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(_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(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 /* Exception flags.  We use the bit positions of the appropriate bits
 101    in the FPSCR, which also correspond to the FE_* bits.  This makes
 102    everything easier ;-).  */
 103 #define FP_EX_INVALID         (1 << (31 - 2))
 104 #define FP_EX_INVALID_SNAN      EFLAG_VXSNAN
 105 #define FP_EX_INVALID_ISI       EFLAG_VXISI
 106 #define FP_EX_INVALID_IDI       EFLAG_VXIDI
 107 #define FP_EX_INVALID_ZDZ       EFLAG_VXZDZ
 108 #define FP_EX_INVALID_IMZ       EFLAG_VXIMZ
 109 #define FP_EX_OVERFLOW        (1 << (31 - 3))
 110 #define FP_EX_UNDERFLOW       (1 << (31 - 4))
 111 #define FP_EX_DIVZERO         (1 << (31 - 5))
 112 #define FP_EX_INEXACT         (1 << (31 - 6))
 113
 114 /* This macro appears to be called when both X and Y are NaNs, and
 115  * has to choose one and copy it to R. i386 goes for the larger of the
 116  * two, sparc64 just picks Y. I don't understand this at all so I'll
 117  * go with sparc64 because it's shorter :->   -- PMM
 118  */
 119 #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP)              \
 120   do {                                                  \
 121     R##_s = Y##_s;                                      \
 122     _FP_FRAC_COPY_##wc(R,Y);                            \
 123     R##_c = FP_CLS_NAN;                                 \
 124   } while (0)
 125
 126
 127 #include <linux/kernel.h>
 128 #include <linux/sched.h>
 129
 130 #define __FPU_FPSCR     (current->thread.fpscr.val)
 131
 132 /* We only actually write to the destination register
 133  * if exceptions signalled (if any) will not trap.
 134  */
 135 #define __FPU_ENABLED_EXC \
 136 ({                                              \
 137         (__FPU_FPSCR >> 3) & 0x1f;      \
 138 })
 139
 140 #define __FPU_TRAP_P(bits) \
 141         ((__FPU_ENABLED_EXC & (bits)) != 0)
 142
 143 #define __FP_PACK_S(val,X)                      \
 144 ({  int __exc = _FP_PACK_CANONICAL(S,1,X);      \
 145     if(!__exc || !__FPU_TRAP_P(__exc))          \
 146         _FP_PACK_RAW_1_P(S,val,X);              \
 147     __exc;                                      \
 148 })
 149
 150 #define __FP_PACK_D(val,X)                      \
 151    do {                                                                 \
 152         _FP_PACK_CANONICAL(D, 2, X);                                    \
 153         if (!FP_CUR_EXCEPTIONS || !__FPU_TRAP_P(FP_CUR_EXCEPTIONS))     \
 154                 _FP_PACK_RAW_2_P(D, val, X);                            \
 155    } while (0)
 156
 157 #define __FP_PACK_DS(val,X)                                                     \
 158    do {                                                                         \
 159            FP_DECL_S(__X);                                                      \
 160            FP_CONV(S, D, 1, 2, __X, X);                                         \
 161            _FP_PACK_CANONICAL(S, 1, __X);                                       \
 162            if (!FP_CUR_EXCEPTIONS || !__FPU_TRAP_P(FP_CUR_EXCEPTIONS)) {        \
 163                    _FP_UNPACK_CANONICAL(S, 1, __X);                             \
 164                    FP_CONV(D, S, 2, 1, X, __X);                                 \
 165                    _FP_PACK_CANONICAL(D, 2, X);                                 \
 166                    if (!FP_CUR_EXCEPTIONS || !__FPU_TRAP_P(FP_CUR_EXCEPTIONS))  \
 167                    _FP_PACK_RAW_2_P(D, val, X);                                 \
 168            }                                                                    \
 169    } while (0)
 170
 171 /* Obtain the current rounding mode. */
 172 #define FP_ROUNDMODE                    \
 173 ({                                      \
 174         __FPU_FPSCR & 0x3;              \
 175 })
 176
 177 /* the asm fragments go here: all these are taken from glibc-2.0.5's
 178  * stdlib/longlong.h
 179  */
 180
 181 #include <linux/types.h>
 182 #include <asm/byteorder.h>
 183
 184 /* add_ssaaaa is used in op-2.h and should be equivalent to
 185  * #define add_ssaaaa(sh,sl,ah,al,bh,bl) (sh = ah+bh+ (( sl = al+bl) < al))
 186  * add_ssaaaa(high_sum, low_sum, high_addend_1, low_addend_1,
 187  * high_addend_2, low_addend_2) adds two UWtype integers, composed by
 188  * HIGH_ADDEND_1 and LOW_ADDEND_1, and HIGH_ADDEND_2 and LOW_ADDEND_2
 189  * respectively.  The result is placed in HIGH_SUM and LOW_SUM.  Overflow
 190  * (i.e. carry out) is not stored anywhere, and is lost.
 191  */
 192 #define add_ssaaaa(sh, sl, ah, al, bh, bl)                              \
 193   do {                                                                  \
 194     if (__builtin_constant_p (bh) && (bh) == 0)                         \
 195       __asm__ ("{a%I4|add%I4c} %1,%3,%4\n\t{aze|addze} %0,%2"           \
 196              : "=r" ((USItype)(sh)),                                    \
 197                "=&r" ((USItype)(sl))                                    \
 198              : "%r" ((USItype)(ah)),                                    \
 199                "%r" ((USItype)(al)),                                    \
 200                "rI" ((USItype)(bl)));                                   \
 201     else if (__builtin_constant_p (bh) && (bh) ==~(USItype) 0)          \
 202       __asm__ ("{a%I4|add%I4c} %1,%3,%4\n\t{ame|addme} %0,%2"           \
 203              : "=r" ((USItype)(sh)),                                    \
 204                "=&r" ((USItype)(sl))                                    \
 205              : "%r" ((USItype)(ah)),                                    \
 206                "%r" ((USItype)(al)),                                    \
 207                "rI" ((USItype)(bl)));                                   \
 208     else                                                                \
 209       __asm__ ("{a%I5|add%I5c} %1,%4,%5\n\t{ae|adde} %0,%2,%3"          \
 210              : "=r" ((USItype)(sh)),                                    \
 211                "=&r" ((USItype)(sl))                                    \
 212              : "%r" ((USItype)(ah)),                                    \
 213                "r" ((USItype)(bh)),                                     \
 214                "%r" ((USItype)(al)),                                    \
 215                "rI" ((USItype)(bl)));                                   \
 216   } while (0)
 217
 218 /* sub_ddmmss is used in op-2.h and udivmodti4.c and should be equivalent to
 219  * #define sub_ddmmss(sh, sl, ah, al, bh, bl) (sh = ah-bh - ((sl = al-bl) > al))
 220  * sub_ddmmss(high_difference, low_difference, high_minuend, low_minuend,
 221  * high_subtrahend, low_subtrahend) subtracts two two-word UWtype integers,
 222  * composed by HIGH_MINUEND_1 and LOW_MINUEND_1, and HIGH_SUBTRAHEND_2 and
 223  * LOW_SUBTRAHEND_2 respectively.  The result is placed in HIGH_DIFFERENCE
 224  * and LOW_DIFFERENCE.  Overflow (i.e. carry out) is not stored anywhere,
 225  * and is lost.
 226  */
 227 #define sub_ddmmss(sh, sl, ah, al, bh, bl)                              \
 228   do {                                                                  \
 229     if (__builtin_constant_p (ah) && (ah) == 0)                         \
 230       __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{sfze|subfze} %0,%2"       \
 231                : "=r" ((USItype)(sh)),                                  \
 232                  "=&r" ((USItype)(sl))                                  \
 233                : "r" ((USItype)(bh)),                                   \
 234                  "rI" ((USItype)(al)),                                  \
 235                  "r" ((USItype)(bl)));                                  \
 236     else if (__builtin_constant_p (ah) && (ah) ==~(USItype) 0)          \
 237       __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{sfme|subfme} %0,%2"       \
 238                : "=r" ((USItype)(sh)),                                  \
 239                  "=&r" ((USItype)(sl))                                  \
 240                : "r" ((USItype)(bh)),                                   \
 241                  "rI" ((USItype)(al)),                                  \
 242                  "r" ((USItype)(bl)));                                  \
 243     else if (__builtin_constant_p (bh) && (bh) == 0)                    \
 244       __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{ame|addme} %0,%2"         \
 245                : "=r" ((USItype)(sh)),                                  \
 246                  "=&r" ((USItype)(sl))                                  \
 247                : "r" ((USItype)(ah)),                                   \
 248                  "rI" ((USItype)(al)),                                  \
 249                  "r" ((USItype)(bl)));                                  \
 250     else if (__builtin_constant_p (bh) && (bh) ==~(USItype) 0)          \
 251       __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{aze|addze} %0,%2"         \
 252                : "=r" ((USItype)(sh)),                                  \
 253                  "=&r" ((USItype)(sl))                                  \
 254                : "r" ((USItype)(ah)),                                   \
 255                  "rI" ((USItype)(al)),                                  \
 256                  "r" ((USItype)(bl)));                                  \
 257     else                                                                \
 258       __asm__ ("{sf%I4|subf%I4c} %1,%5,%4\n\t{sfe|subfe} %0,%3,%2"      \
 259                : "=r" ((USItype)(sh)),                                  \
 260                  "=&r" ((USItype)(sl))                                  \
 261                : "r" ((USItype)(ah)),                                   \
 262                  "r" ((USItype)(bh)),                                   \
 263                  "rI" ((USItype)(al)),                                  \
 264                  "r" ((USItype)(bl)));                                  \
 265   } while (0)
 266
 267 /* asm fragments for mul and div */
 268
 269 /* umul_ppmm(high_prod, low_prod, multipler, multiplicand) multiplies two
 270  * UWtype integers MULTIPLER and MULTIPLICAND, and generates a two UWtype
 271  * word product in HIGH_PROD and LOW_PROD.
 272  */
 273 #define umul_ppmm(ph, pl, m0, m1)                                       \
 274   do {                                                                  \
 275     USItype __m0 = (m0), __m1 = (m1);                                   \
 276     __asm__ ("mulhwu %0,%1,%2"                                          \
 277              : "=r" ((USItype)(ph))                                     \
 278              : "%r" (__m0),                                             \
 279                "r" (__m1));                                             \
 280     (pl) = __m0 * __m1;                                                 \
 281   } while (0)
 282
 283 /* udiv_qrnnd(quotient, remainder, high_numerator, low_numerator,
 284  * denominator) divides a UDWtype, composed by the UWtype integers
 285  * HIGH_NUMERATOR and LOW_NUMERATOR, by DENOMINATOR and places the quotient
 286  * in QUOTIENT and the remainder in REMAINDER.  HIGH_NUMERATOR must be less
 287  * than DENOMINATOR for correct operation.  If, in addition, the most
 288  * significant bit of DENOMINATOR must be 1, then the pre-processor symbol
 289  * UDIV_NEEDS_NORMALIZATION is defined to 1.
 290  */
 291 #define udiv_qrnnd(q, r, n1, n0, d)                                     \
 292   do {                                                                  \
 293     UWtype __d1, __d0, __q1, __q0, __r1, __r0, __m;                     \
 294     __d1 = __ll_highpart (d);                                           \
 295     __d0 = __ll_lowpart (d);                                            \
 296                                                                         \
 297     __r1 = (n1) % __d1;                                                 \
 298     __q1 = (n1) / __d1;                                                 \
 299     __m = (UWtype) __q1 * __d0;                                         \
 300     __r1 = __r1 * __ll_B | __ll_highpart (n0);                          \
 301     if (__r1 < __m)                                                     \
 302       {                                                                 \
 303         __q1--, __r1 += (d);                                            \
 304         if (__r1 >= (d)) /* we didn't get carry when adding to __r1 */  \
 305           if (__r1 < __m)                                               \
 306             __q1--, __r1 += (d);                                        \
 307       }                                                                 \
 308     __r1 -= __m;                                                        \
 309                                                                         \
 310     __r0 = __r1 % __d1;                                                 \
 311     __q0 = __r1 / __d1;                                                 \
 312     __m = (UWtype) __q0 * __d0;                                         \
 313     __r0 = __r0 * __ll_B | __ll_lowpart (n0);                           \
 314     if (__r0 < __m)                                                     \
 315       {                                                                 \
 316         __q0--, __r0 += (d);                                            \
 317         if (__r0 >= (d))                                                \
 318           if (__r0 < __m)                                               \
 319             __q0--, __r0 += (d);                                        \
 320       }                                                                 \
 321     __r0 -= __m;                                                        \
 322                                                                         \
 323     (q) = (UWtype) __q1 * __ll_B | __q0;                                \
 324     (r) = __r0;                                                         \
 325   } while (0)
 326
 327 #define UDIV_NEEDS_NORMALIZATION 1
 328
 329 #define abort()                                                         \
 330         return 0
 331
 332 #ifdef __BIG_ENDIAN
 333 #define __BYTE_ORDER __BIG_ENDIAN
 334 #else
 335 #define __BYTE_ORDER __LITTLE_ENDIAN
 336 #endif
 337
 338 /* Exception flags. */
 339 #define EFLAG_INVALID           (1 << (31 - 2))
 340 #define EFLAG_OVERFLOW          (1 << (31 - 3))
 341 #define EFLAG_UNDERFLOW         (1 << (31 - 4))
 342 #define EFLAG_DIVZERO           (1 << (31 - 5))
 343 #define EFLAG_INEXACT           (1 << (31 - 6))
 344
 345 #define EFLAG_VXSNAN            (1 << (31 - 7))
 346 #define EFLAG_VXISI             (1 << (31 - 8))
 347 #define EFLAG_VXIDI             (1 << (31 - 9))
 348 #define EFLAG_VXZDZ             (1 << (31 - 10))
 349 #define EFLAG_VXIMZ             (1 << (31 - 11))
 350 #define EFLAG_VXVC              (1 << (31 - 12))
 351 #define EFLAG_VXSOFT            (1 << (31 - 21))
 352 #define EFLAG_VXSQRT            (1 << (31 - 22))
 353 #define EFLAG_VXCVI             (1 << (31 - 23))