target-alpha/vax_helper.c

   1 /*
   2  *  Helpers for vax floating point instructions.
   3  *
   4  *  Copyright (c) 2007 Jocelyn Mayer
   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, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "cpu.h"
  22 #include "exec/helper-proto.h"
  23 #include "fpu/softfloat.h"
  24
  25 #define FP_STATUS (env->fp_status)
  26
  27
  28 /* F floating (VAX) */
  29 static uint64_t float32_to_f(float32 fa)
  30 {
  31     uint64_t r, exp, mant, sig;
  32     CPU_FloatU a;
  33
  34     a.f = fa;
  35     sig = ((uint64_t)a.l & 0x80000000) << 32;
  36     exp = (a.l >> 23) & 0xff;
  37     mant = ((uint64_t)a.l & 0x007fffff) << 29;
  38
  39     if (exp == 255) {
  40         /* NaN or infinity */
  41         r = 1; /* VAX dirty zero */
  42     } else if (exp == 0) {
  43         if (mant == 0) {
  44             /* Zero */
  45             r = 0;
  46         } else {
  47             /* Denormalized */
  48             r = sig | ((exp + 1) << 52) | mant;
  49         }
  50     } else {
  51         if (exp >= 253) {
  52             /* Overflow */
  53             r = 1; /* VAX dirty zero */
  54         } else {
  55             r = sig | ((exp + 2) << 52);
  56         }
  57     }
  58
  59     return r;
  60 }
  61
  62 static float32 f_to_float32(CPUAlphaState *env, uintptr_t retaddr, uint64_t a)
  63 {
  64     uint32_t exp, mant_sig;
  65     CPU_FloatU r;
  66
  67     exp = ((a >> 55) & 0x80) | ((a >> 52) & 0x7f);
  68     mant_sig = ((a >> 32) & 0x80000000) | ((a >> 29) & 0x007fffff);
  69
  70     if (unlikely(!exp && mant_sig)) {
  71         /* Reserved operands / Dirty zero */
  72         dynamic_excp(env, retaddr, EXCP_OPCDEC, 0);
  73     }
  74
  75     if (exp < 3) {
  76         /* Underflow */
  77         r.l = 0;
  78     } else {
  79         r.l = ((exp - 2) << 23) | mant_sig;
  80     }
  81
  82     return r.f;
  83 }
  84
  85 uint32_t helper_f_to_memory(uint64_t a)
  86 {
  87     uint32_t r;
  88     r =  (a & 0x00001fffe0000000ull) >> 13;
  89     r |= (a & 0x07ffe00000000000ull) >> 45;
  90     r |= (a & 0xc000000000000000ull) >> 48;
  91     return r;
  92 }
  93
  94 uint64_t helper_memory_to_f(uint32_t a)
  95 {
  96     uint64_t r;
  97     r =  ((uint64_t)(a & 0x0000c000)) << 48;
  98     r |= ((uint64_t)(a & 0x003fffff)) << 45;
  99     r |= ((uint64_t)(a & 0xffff0000)) << 13;
 100     if (!(a & 0x00004000)) {
 101         r |= 0x7ll << 59;
 102     }
 103     return r;
 104 }
 105
 106 /* ??? Emulating VAX arithmetic with IEEE arithmetic is wrong.  We should
 107    either implement VAX arithmetic properly or just signal invalid opcode.  */
 108
 109 uint64_t helper_addf(CPUAlphaState *env, uint64_t a, uint64_t b)
 110 {
 111     float32 fa, fb, fr;
 112
 113     fa = f_to_float32(env, GETPC(), a);
 114     fb = f_to_float32(env, GETPC(), b);
 115     fr = float32_add(fa, fb, &FP_STATUS);
 116     return float32_to_f(fr);
 117 }
 118
 119 uint64_t helper_subf(CPUAlphaState *env, uint64_t a, uint64_t b)
 120 {
 121     float32 fa, fb, fr;
 122
 123     fa = f_to_float32(env, GETPC(), a);
 124     fb = f_to_float32(env, GETPC(), b);
 125     fr = float32_sub(fa, fb, &FP_STATUS);
 126     return float32_to_f(fr);
 127 }
 128
 129 uint64_t helper_mulf(CPUAlphaState *env, uint64_t a, uint64_t b)
 130 {
 131     float32 fa, fb, fr;
 132
 133     fa = f_to_float32(env, GETPC(), a);
 134     fb = f_to_float32(env, GETPC(), b);
 135     fr = float32_mul(fa, fb, &FP_STATUS);
 136     return float32_to_f(fr);
 137 }
 138
 139 uint64_t helper_divf(CPUAlphaState *env, uint64_t a, uint64_t b)
 140 {
 141     float32 fa, fb, fr;
 142
 143     fa = f_to_float32(env, GETPC(), a);
 144     fb = f_to_float32(env, GETPC(), b);
 145     fr = float32_div(fa, fb, &FP_STATUS);
 146     return float32_to_f(fr);
 147 }
 148
 149 uint64_t helper_sqrtf(CPUAlphaState *env, uint64_t t)
 150 {
 151     float32 ft, fr;
 152
 153     ft = f_to_float32(env, GETPC(), t);
 154     fr = float32_sqrt(ft, &FP_STATUS);
 155     return float32_to_f(fr);
 156 }
 157
 158
 159 /* G floating (VAX) */
 160 static uint64_t float64_to_g(float64 fa)
 161 {
 162     uint64_t r, exp, mant, sig;
 163     CPU_DoubleU a;
 164
 165     a.d = fa;
 166     sig = a.ll & 0x8000000000000000ull;
 167     exp = (a.ll >> 52) & 0x7ff;
 168     mant = a.ll & 0x000fffffffffffffull;
 169
 170     if (exp == 2047) {
 171         /* NaN or infinity */
 172         r = 1; /* VAX dirty zero */
 173     } else if (exp == 0) {
 174         if (mant == 0) {
 175             /* Zero */
 176             r = 0;
 177         } else {
 178             /* Denormalized */
 179             r = sig | ((exp + 1) << 52) | mant;
 180         }
 181     } else {
 182         if (exp >= 2045) {
 183             /* Overflow */
 184             r = 1; /* VAX dirty zero */
 185         } else {
 186             r = sig | ((exp + 2) << 52);
 187         }
 188     }
 189
 190     return r;
 191 }
 192
 193 static float64 g_to_float64(CPUAlphaState *env, uintptr_t retaddr, uint64_t a)
 194 {
 195     uint64_t exp, mant_sig;
 196     CPU_DoubleU r;
 197
 198     exp = (a >> 52) & 0x7ff;
 199     mant_sig = a & 0x800fffffffffffffull;
 200
 201     if (!exp && mant_sig) {
 202         /* Reserved operands / Dirty zero */
 203         dynamic_excp(env, retaddr, EXCP_OPCDEC, 0);
 204     }
 205
 206     if (exp < 3) {
 207         /* Underflow */
 208         r.ll = 0;
 209     } else {
 210         r.ll = ((exp - 2) << 52) | mant_sig;
 211     }
 212
 213     return r.d;
 214 }
 215
 216 uint64_t helper_g_to_memory(uint64_t a)
 217 {
 218     uint64_t r;
 219     r =  (a & 0x000000000000ffffull) << 48;
 220     r |= (a & 0x00000000ffff0000ull) << 16;
 221     r |= (a & 0x0000ffff00000000ull) >> 16;
 222     r |= (a & 0xffff000000000000ull) >> 48;
 223     return r;
 224 }
 225
 226 uint64_t helper_memory_to_g(uint64_t a)
 227 {
 228     uint64_t r;
 229     r =  (a & 0x000000000000ffffull) << 48;
 230     r |= (a & 0x00000000ffff0000ull) << 16;
 231     r |= (a & 0x0000ffff00000000ull) >> 16;
 232     r |= (a & 0xffff000000000000ull) >> 48;
 233     return r;
 234 }
 235
 236 uint64_t helper_addg(CPUAlphaState *env, uint64_t a, uint64_t b)
 237 {
 238     float64 fa, fb, fr;
 239
 240     fa = g_to_float64(env, GETPC(), a);
 241     fb = g_to_float64(env, GETPC(), b);
 242     fr = float64_add(fa, fb, &FP_STATUS);
 243     return float64_to_g(fr);
 244 }
 245
 246 uint64_t helper_subg(CPUAlphaState *env, uint64_t a, uint64_t b)
 247 {
 248     float64 fa, fb, fr;
 249
 250     fa = g_to_float64(env, GETPC(), a);
 251     fb = g_to_float64(env, GETPC(), b);
 252     fr = float64_sub(fa, fb, &FP_STATUS);
 253     return float64_to_g(fr);
 254 }
 255
 256 uint64_t helper_mulg(CPUAlphaState *env, uint64_t a, uint64_t b)
 257 {
 258     float64 fa, fb, fr;
 259
 260     fa = g_to_float64(env, GETPC(), a);
 261     fb = g_to_float64(env, GETPC(), b);
 262     fr = float64_mul(fa, fb, &FP_STATUS);
 263     return float64_to_g(fr);
 264 }
 265
 266 uint64_t helper_divg(CPUAlphaState *env, uint64_t a, uint64_t b)
 267 {
 268     float64 fa, fb, fr;
 269
 270     fa = g_to_float64(env, GETPC(), a);
 271     fb = g_to_float64(env, GETPC(), b);
 272     fr = float64_div(fa, fb, &FP_STATUS);
 273     return float64_to_g(fr);
 274 }
 275
 276 uint64_t helper_sqrtg(CPUAlphaState *env, uint64_t a)
 277 {
 278     float64 fa, fr;
 279
 280     fa = g_to_float64(env, GETPC(), a);
 281     fr = float64_sqrt(fa, &FP_STATUS);
 282     return float64_to_g(fr);
 283 }
 284
 285 uint64_t helper_cmpgeq(CPUAlphaState *env, uint64_t a, uint64_t b)
 286 {
 287     float64 fa, fb;
 288
 289     fa = g_to_float64(env, GETPC(), a);
 290     fb = g_to_float64(env, GETPC(), b);
 291
 292     if (float64_eq_quiet(fa, fb, &FP_STATUS)) {
 293         return 0x4000000000000000ULL;
 294     } else {
 295         return 0;
 296     }
 297 }
 298
 299 uint64_t helper_cmpgle(CPUAlphaState *env, uint64_t a, uint64_t b)
 300 {
 301     float64 fa, fb;
 302
 303     fa = g_to_float64(env, GETPC(), a);
 304     fb = g_to_float64(env, GETPC(), b);
 305
 306     if (float64_le(fa, fb, &FP_STATUS)) {
 307         return 0x4000000000000000ULL;
 308     } else {
 309         return 0;
 310     }
 311 }
 312
 313 uint64_t helper_cmpglt(CPUAlphaState *env, uint64_t a, uint64_t b)
 314 {
 315     float64 fa, fb;
 316
 317     fa = g_to_float64(env, GETPC(), a);
 318     fb = g_to_float64(env, GETPC(), b);
 319
 320     if (float64_lt(fa, fb, &FP_STATUS)) {
 321         return 0x4000000000000000ULL;
 322     } else {
 323         return 0;
 324     }
 325 }
 326
 327 uint64_t helper_cvtqf(CPUAlphaState *env, uint64_t a)
 328 {
 329     float32 fr = int64_to_float32(a, &FP_STATUS);
 330     return float32_to_f(fr);
 331 }
 332
 333 uint64_t helper_cvtgf(CPUAlphaState *env, uint64_t a)
 334 {
 335     float64 fa;
 336     float32 fr;
 337
 338     fa = g_to_float64(env, GETPC(), a);
 339     fr = float64_to_float32(fa, &FP_STATUS);
 340     return float32_to_f(fr);
 341 }
 342
 343 uint64_t helper_cvtgq(CPUAlphaState *env, uint64_t a)
 344 {
 345     float64 fa = g_to_float64(env, GETPC(), a);
 346     return float64_to_int64_round_to_zero(fa, &FP_STATUS);
 347 }
 348
 349 uint64_t helper_cvtqg(CPUAlphaState *env, uint64_t a)
 350 {
 351     float64 fr;
 352     fr = int64_to_float64(a, &FP_STATUS);
 353     return float64_to_g(fr);
 354 }