target-arm/op_helper.c

   1 /*
   2  *  ARM helper routines
   3  *
   4  *  Copyright (c) 2005 CodeSourcery, LLC
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <math.h>
  22 #include <fenv.h>
  23 #include "exec.h"
  24
  25 /* If the host doesn't define C99 math intrinsics then use the normal
  26    operators.  This may generate excess exceptions, but it's probably
  27    near enough for most things.  */
  28 #ifndef isless
  29 #define isless(x, y) (x < y)
  30 #endif
  31 #ifndef isgreater
  32 #define isgreater(x, y) (x > y)
  33 #endif
  34 #ifndef isunordered
  35 #define isunordered(x, y) (!((x < y) || (x >= y)))
  36 #endif
  37
  38 void raise_exception(int tt)
  39 {
  40     env->exception_index = tt;
  41     cpu_loop_exit();
  42 }
  43
  44 /* thread support */
  45
  46 spinlock_t global_cpu_lock = SPIN_LOCK_UNLOCKED;
  47
  48 void cpu_lock(void)
  49 {
  50     spin_lock(&global_cpu_lock);
  51 }
  52
  53 void cpu_unlock(void)
  54 {
  55     spin_unlock(&global_cpu_lock);
  56 }
  57
  58 /* VFP support.  */
  59
  60 void do_vfp_abss(void)
  61 {
  62   FT0s = fabsf(FT0s);
  63 }
  64
  65 void do_vfp_absd(void)
  66 {
  67   FT0d = fabs(FT0d);
  68 }
  69
  70 void do_vfp_sqrts(void)
  71 {
  72   FT0s = sqrtf(FT0s);
  73 }
  74
  75 void do_vfp_sqrtd(void)
  76 {
  77   FT0d = sqrt(FT0d);
  78 }
  79
  80 /* We use an == operator first to generate teh correct floating point
  81    exception.  Subsequent comparisons use the exception-safe macros.  */
  82 #define DO_VFP_cmp(p)                     \
  83 void do_vfp_cmp##p(void)                  \
  84 {                                         \
  85     uint32_t flags;                       \
  86     if (FT0##p == FT1##p)                 \
  87         flags = 0xc;                      \
  88     else if (isless (FT0##p, FT1##p))     \
  89         flags = 0x8;                      \
  90     else if (isgreater (FT0##p, FT1##p))  \
  91         flags = 0x2;                      \
  92     else /* unordered */                  \
  93         flags = 0x3;                      \
  94     env->vfp.fpscr = (flags << 28) | (env->vfp.fpscr & 0x0fffffff); \
  95     FORCE_RET();                          \
  96 }
  97 DO_VFP_cmp(s)
  98 DO_VFP_cmp(d)
  99 #undef DO_VFP_cmp
 100
 101 /* We use a > operator first to get FP exceptions right.  */
 102 #define DO_VFP_cmpe(p)                      \
 103 void do_vfp_cmpe##p(void)                   \
 104 {                                           \
 105     uint32_t flags;                         \
 106     if (FT0##p > FT1##p)                    \
 107         flags = 0x2;                        \
 108     else if (isless (FT0##p, FT1##p))       \
 109         flags = 0x8;                        \
 110     else if (isunordered (FT0##p, FT1##p))  \
 111         flags = 0x3;                        \
 112     else /* equal */                        \
 113         flags = 0xc;                        \
 114     env->vfp.fpscr = (flags << 28) | (env->vfp.fpscr & 0x0fffffff); \
 115     FORCE_RET();                            \
 116 }
 117 DO_VFP_cmpe(s)
 118 DO_VFP_cmpe(d)
 119 #undef DO_VFP_cmpe
 120
 121 /* Convert host exception flags to vfp form.  */
 122 int vfp_exceptbits_from_host(int host_bits)
 123 {
 124     int target_bits = 0;
 125
 126 #ifdef FE_INVALID
 127     if (host_bits & FE_INVALID)
 128         target_bits |= 1;
 129 #endif
 130 #ifdef FE_DIVBYZERO
 131     if (host_bits & FE_DIVBYZERO)
 132         target_bits |= 2;
 133 #endif
 134 #ifdef FE_OVERFLOW
 135     if (host_bits & FE_OVERFLOW)
 136         target_bits |= 4;
 137 #endif
 138 #ifdef FE_UNDERFLOW
 139     if (host_bits & FE_UNDERFLOW)
 140         target_bits |= 8;
 141 #endif
 142 #ifdef FE_INEXACT
 143     if (host_bits & FE_INEXACT)
 144         target_bits |= 0x10;
 145 #endif
 146     /* C doesn't define an inexact exception.  */
 147     return target_bits;
 148 }
 149
 150 /* Convert vfp exception flags to target form.  */
 151 int vfp_host_exceptbits_to_host(int target_bits)
 152 {
 153     int host_bits = 0;
 154
 155 #ifdef FE_INVALID
 156     if (target_bits & 1)
 157         host_bits |= FE_INVALID;
 158 #endif
 159 #ifdef FE_DIVBYZERO
 160     if (target_bits & 2)
 161         host_bits |= FE_DIVBYZERO;
 162 #endif
 163 #ifdef FE_OVERFLOW
 164     if (target_bits & 4)
 165         host_bits |= FE_OVERFLOW;
 166 #endif
 167 #ifdef FE_UNDERFLOW
 168     if (target_bits & 8)
 169         host_bits |= FE_UNDERFLOW;
 170 #endif
 171 #ifdef FE_INEXACT
 172     if (target_bits & 0x10)
 173         host_bits |= FE_INEXACT;
 174 #endif
 175     return host_bits;
 176 }
 177
 178 void do_vfp_set_fpscr(void)
 179 {
 180     int i;
 181     uint32_t changed;
 182
 183     changed = env->vfp.fpscr;
 184     env->vfp.fpscr = (T0 & 0xffc8ffff);
 185     env->vfp.vec_len = (T0 >> 16) & 7;
 186     env->vfp.vec_stride = (T0 >> 20) & 3;
 187
 188     changed ^= T0;
 189     if (changed & (3 << 22)) {
 190         i = (T0 >> 22) & 3;
 191         switch (i) {
 192         case 0:
 193             i = FE_TONEAREST;
 194             break;
 195         case 1:
 196             i = FE_UPWARD;
 197             break;
 198         case 2:
 199             i = FE_DOWNWARD;
 200             break;
 201         case 3:
 202             i = FE_TOWARDZERO;
 203             break;
 204         }
 205         fesetround (i);
 206     }
 207
 208     /* Clear host exception flags.  */
 209     feclearexcept(FE_ALL_EXCEPT);
 210
 211 #ifdef feenableexcept
 212     if (changed & 0x1f00) {
 213         i = vfp_exceptbits_to_host((T0 >> 8) & 0x1f);
 214         feenableexcept (i);
 215         fedisableexcept (FE_ALL_EXCEPT & ~i);
 216     }
 217 #endif
 218     /* XXX: FZ and DN are not implemented.  */
 219 }
 220
 221 void do_vfp_get_fpscr(void)
 222 {
 223     int i;
 224
 225     T0 = (env->vfp.fpscr & 0xffc8ffff) | (env->vfp.vec_len << 16)
 226           | (env->vfp.vec_stride << 20);
 227     i = fetestexcept(FE_ALL_EXCEPT);
 228     T0 |= vfp_exceptbits_from_host(i);
 229 }