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 2.1 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/exec-all.h"
  23 #include "exec/helper-proto.h"
  24 #include "fpu/softfloat.h"
  25
  26 #define FP_STATUS (env->fp_status)
  27
  28
  29 /* F floating (VAX) */
  30 static uint64_t float32_to_f(float32 fa)
  31 {
  32     uint64_t r, exp, mant, sig;
  33     CPU_FloatU a;
  34
  35     a.f = fa;
  36     sig = ((uint64_t)a.l & 0x80000000) << 32;
  37     exp = (a.l >> 23) & 0xff;
  38     mant = ((uint64_t)a.l & 0x007fffff) << 29;
  39
  40     if (exp == 255) {
  41         /* NaN or infinity */
  42         r = 1; /* VAX dirty zero */
  43     } else if (exp == 0) {
  44         if (mant == 0) {
  45             /* Zero */
  46             r = 0;
  47         } else {
  48             /* Denormalized */
  49             r = sig | ((exp + 1) << 52) | mant;
  50         }
  51     } else {
  52         if (exp >= 253) {
  53             /* Overflow */
  54             r = 1; /* VAX dirty zero */
  55         } else {
  56             r = sig | ((exp + 2) << 52);
  57         }
  58     }
  59
  60     return r;
  61 }
  62
  63 static float32 f_to_float32(CPUAlphaState *env, uintptr_t retaddr, uint64_t a)
  64 {
  65     uint32_t exp, mant_sig;
  66     CPU_FloatU r;
  67
  68     exp = ((a >> 55) & 0x80) | ((a >> 52) & 0x7f);
  69     mant_sig = ((a >> 32) & 0x80000000) | ((a >> 29) & 0x007fffff);
  70
  71     if (unlikely(!exp && mant_sig)) {
  72         /* Reserved operands / Dirty zero */
  73         dynamic_excp(env, retaddr, EXCP_OPCDEC, 0);
  74     }
  75
  76     if (exp < 3) {
  77         /* Underflow */
  78         r.l = 0;
  79     } else {
  80         r.l = ((exp - 2) << 23) | mant_sig;
  81     }
  82
  83     return r.f;
  84 }
  85
  86 uint32_t helper_f_to_memory(uint64_t a)
  87 {
  88     uint32_t r;
  89     r =  (a & 0x00001fffe0000000ull) >> 13;
  90     r |= (a & 0x07ffe00000000000ull) >> 45;
  91     r |= (a & 0xc000000000000000ull) >> 48;
  92     return r;
  93 }
  94
  95 uint64_t helper_memory_to_f(uint32_t a)
  96 {
  97     uint64_t r;
  98     r =  ((uint64_t)(a & 0x0000c000)) << 48;
  99     r |= ((uint64_t)(a & 0x003fffff)) << 45;
 100     r |= ((uint64_t)(a & 0xffff0000)) << 13;
 101     if (!(a & 0x00004000)) {
 102         r |= 0x7ll << 59;
 103     }
 104     return r;
 105 }
 106
 107 /* ??? Emulating VAX arithmetic with IEEE arithmetic is wrong.  We should
 108    either implement VAX arithmetic properly or just signal invalid opcode.  */
 109
 110 uint64_t helper_addf(CPUAlphaState *env, uint64_t a, uint64_t b)
 111 {
 112     float32 fa, fb, fr;
 113
 114     fa = f_to_float32(env, GETPC(), a);
 115     fb = f_to_float32(env, GETPC(), b);
 116     fr = float32_add(fa, fb, &FP_STATUS);
 117     return float32_to_f(fr);
 118 }
 119
 120 uint64_t helper_subf(CPUAlphaState *env, uint64_t a, uint64_t b)
 121 {
 122     float32 fa, fb, fr;
 123
 124     fa = f_to_float32(env, GETPC(), a);
 125     fb = f_to_float32(env, GETPC(), b);
 126     fr = float32_sub(fa, fb, &FP_STATUS);
 127     return float32_to_f(fr);
 128 }
 129
 130 uint64_t helper_mulf(CPUAlphaState *env, uint64_t a, uint64_t b)
 131 {
 132     float32 fa, fb, fr;
 133
 134     fa = f_to_float32(env, GETPC(), a);
 135     fb = f_to_float32(env, GETPC(), b);
 136     fr = float32_mul(fa, fb, &FP_STATUS);
 137     return float32_to_f(fr);
 138 }
 139
 140 uint64_t helper_divf(CPUAlphaState *env, uint64_t a, uint64_t b)
 141 {
 142     float32 fa, fb, fr;
 143
 144     fa = f_to_float32(env, GETPC(), a);
 145     fb = f_to_float32(env, GETPC(), b);
 146     fr = float32_div(fa, fb, &FP_STATUS);
 147     return float32_to_f(fr);
 148 }
 149
 150 uint64_t helper_sqrtf(CPUAlphaState *env, uint64_t t)
 151 {
 152     float32 ft, fr;
 153
 154     ft = f_to_float32(env, GETPC(), t);
 155     fr = float32_sqrt(ft, &FP_STATUS);
 156     return float32_to_f(fr);
 157 }
 158
 159
 160 /* G floating (VAX) */
 161 static uint64_t float64_to_g(float64 fa)
 162 {
 163     uint64_t r, exp, mant, sig;
 164     CPU_DoubleU a;
 165
 166     a.d = fa;
 167     sig = a.ll & 0x8000000000000000ull;
 168     exp = (a.ll >> 52) & 0x7ff;
 169     mant = a.ll & 0x000fffffffffffffull;
 170
 171     if (exp == 2047) {
 172         /* NaN or infinity */
 173         r = 1; /* VAX dirty zero */
 174     } else if (exp == 0) {
 175         if (mant == 0) {
 176             /* Zero */
 177             r = 0;
 178         } else {
 179             /* Denormalized */
 180             r = sig | ((exp + 1) << 52) | mant;
 181         }
 182     } else {
 183         if (exp >= 2045) {
 184             /* Overflow */
 185             r = 1; /* VAX dirty zero */
 186         } else {
 187             r = sig | ((exp + 2) << 52);
 188         }
 189     }
 190
 191     return r;
 192 }
 193
 194 static float64 g_to_float64(CPUAlphaState *env, uintptr_t retaddr, uint64_t a)
 195 {
 196     uint64_t exp, mant_sig;
 197     CPU_DoubleU r;
 198
 199     exp = (a >> 52) & 0x7ff;
 200     mant_sig = a & 0x800fffffffffffffull;
 201
 202     if (!exp && mant_sig) {
 203         /* Reserved operands / Dirty zero */
 204         dynamic_excp(env, retaddr, EXCP_OPCDEC, 0);
 205     }
 206
 207     if (exp < 3) {
 208         /* Underflow */
 209         r.ll = 0;
 210     } else {
 211         r.ll = ((exp - 2) << 52) | mant_sig;
 212     }
 213
 214     return r.d;
 215 }
 216
 217 uint64_t helper_g_to_memory(uint64_t a)
 218 {
 219     uint64_t r;
 220     r =  (a & 0x000000000000ffffull) << 48;
 221     r |= (a & 0x00000000ffff0000ull) << 16;
 222     r |= (a & 0x0000ffff00000000ull) >> 16;
 223     r |= (a & 0xffff000000000000ull) >> 48;
 224     return r;
 225 }
 226
 227 uint64_t helper_memory_to_g(uint64_t a)
 228 {
 229     uint64_t r;
 230     r =  (a & 0x000000000000ffffull) << 48;
 231     r |= (a & 0x00000000ffff0000ull) << 16;
 232     r |= (a & 0x0000ffff00000000ull) >> 16;
 233     r |= (a & 0xffff000000000000ull) >> 48;
 234     return r;
 235 }
 236
 237 uint64_t helper_addg(CPUAlphaState *env, uint64_t a, uint64_t b)
 238 {
 239     float64 fa, fb, fr;
 240
 241     fa = g_to_float64(env, GETPC(), a);
 242     fb = g_to_float64(env, GETPC(), b);
 243     fr = float64_add(fa, fb, &FP_STATUS);
 244     return float64_to_g(fr);
 245 }
 246
 247 uint64_t helper_subg(CPUAlphaState *env, uint64_t a, uint64_t b)
 248 {
 249     float64 fa, fb, fr;
 250
 251     fa = g_to_float64(env, GETPC(), a);
 252     fb = g_to_float64(env, GETPC(), b);
 253     fr = float64_sub(fa, fb, &FP_STATUS);
 254     return float64_to_g(fr);
 255 }
 256
 257 uint64_t helper_mulg(CPUAlphaState *env, uint64_t a, uint64_t b)
 258 {
 259     float64 fa, fb, fr;
 260
 261     fa = g_to_float64(env, GETPC(), a);
 262     fb = g_to_float64(env, GETPC(), b);
 263     fr = float64_mul(fa, fb, &FP_STATUS);
 264     return float64_to_g(fr);
 265 }
 266
 267 uint64_t helper_divg(CPUAlphaState *env, uint64_t a, uint64_t b)
 268 {
 269     float64 fa, fb, fr;
 270
 271     fa = g_to_float64(env, GETPC(), a);
 272     fb = g_to_float64(env, GETPC(), b);
 273     fr = float64_div(fa, fb, &FP_STATUS);
 274     return float64_to_g(fr);
 275 }
 276
 277 uint64_t helper_sqrtg(CPUAlphaState *env, uint64_t a)
 278 {
 279     float64 fa, fr;
 280
 281     fa = g_to_float64(env, GETPC(), a);
 282     fr = float64_sqrt(fa, &FP_STATUS);
 283     return float64_to_g(fr);
 284 }
 285
 286 uint64_t helper_cmpgeq(CPUAlphaState *env, uint64_t a, uint64_t b)
 287 {
 288     float64 fa, fb;
 289
 290     fa = g_to_float64(env, GETPC(), a);
 291     fb = g_to_float64(env, GETPC(), b);
 292
 293     if (float64_eq_quiet(fa, fb, &FP_STATUS)) {
 294         return 0x4000000000000000ULL;
 295     } else {
 296         return 0;
 297     }
 298 }
 299
 300 uint64_t helper_cmpgle(CPUAlphaState *env, uint64_t a, uint64_t b)
 301 {
 302     float64 fa, fb;
 303
 304     fa = g_to_float64(env, GETPC(), a);
 305     fb = g_to_float64(env, GETPC(), b);
 306
 307     if (float64_le(fa, fb, &FP_STATUS)) {
 308         return 0x4000000000000000ULL;
 309     } else {
 310         return 0;
 311     }
 312 }
 313
 314 uint64_t helper_cmpglt(CPUAlphaState *env, uint64_t a, uint64_t b)
 315 {
 316     float64 fa, fb;
 317
 318     fa = g_to_float64(env, GETPC(), a);
 319     fb = g_to_float64(env, GETPC(), b);
 320
 321     if (float64_lt(fa, fb, &FP_STATUS)) {
 322         return 0x4000000000000000ULL;
 323     } else {
 324         return 0;
 325     }
 326 }
 327
 328 uint64_t helper_cvtqf(CPUAlphaState *env, uint64_t a)
 329 {
 330     float32 fr = int64_to_float32(a, &FP_STATUS);
 331     return float32_to_f(fr);
 332 }
 333
 334 uint64_t helper_cvtgf(CPUAlphaState *env, uint64_t a)
 335 {
 336     float64 fa;
 337     float32 fr;
 338
 339     fa = g_to_float64(env, GETPC(), a);
 340     fr = float64_to_float32(fa, &FP_STATUS);
 341     return float32_to_f(fr);
 342 }
 343
 344 uint64_t helper_cvtgq(CPUAlphaState *env, uint64_t a)
 345 {
 346     float64 fa = g_to_float64(env, GETPC(), a);
 347     return float64_to_int64_round_to_zero(fa, &FP_STATUS);
 348 }
 349
 350 uint64_t helper_cvtqg(CPUAlphaState *env, uint64_t a)
 351 {
 352     float64 fr;
 353     fr = int64_to_float64(a, &FP_STATUS);
 354     return float64_to_g(fr);
 355 }