target/i386/hvf/x86_flags.c

   1 /////////////////////////////////////////////////////////////////////////
   2 //
   3 //  Copyright (C) 2001-2012  The Bochs Project
   4 //  Copyright (C) 2017 Google Inc.
   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, write to the Free Software
  18 //  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA B 02110-1301 USA
  19 /////////////////////////////////////////////////////////////////////////
  20 /*
  21  * flags functions
  22  */
  23
  24 #include "qemu/osdep.h"
  25
  26 #include "qemu-common.h"
  27 #include "panic.h"
  28 #include "cpu.h"
  29 #include "x86_flags.h"
  30 #include "x86.h"
  31
  32
  33 /* this is basically bocsh code */
  34
  35 #define LF_SIGN_BIT     31
  36
  37 #define LF_BIT_SD      (0)          /* lazy Sign Flag Delta            */
  38 #define LF_BIT_AF      (3)          /* lazy Adjust flag                */
  39 #define LF_BIT_PDB     (8)          /* lazy Parity Delta Byte (8 bits) */
  40 #define LF_BIT_CF      (31)         /* lazy Carry Flag                 */
  41 #define LF_BIT_PO      (30)         /* lazy Partial Overflow = CF ^ OF */
  42
  43 #define LF_MASK_SD     (0x01 << LF_BIT_SD)
  44 #define LF_MASK_AF     (0x01 << LF_BIT_AF)
  45 #define LF_MASK_PDB    (0xFF << LF_BIT_PDB)
  46 #define LF_MASK_CF     (0x01 << LF_BIT_CF)
  47 #define LF_MASK_PO     (0x01 << LF_BIT_PO)
  48
  49 #define ADD_COUT_VEC(op1, op2, result) \
  50    (((op1) & (op2)) | (((op1) | (op2)) & (~(result))))
  51
  52 #define SUB_COUT_VEC(op1, op2, result) \
  53    (((~(op1)) & (op2)) | (((~(op1)) ^ (op2)) & (result)))
  54
  55 #define GET_ADD_OVERFLOW(op1, op2, result, mask) \
  56    ((((op1) ^ (result)) & ((op2) ^ (result))) & (mask))
  57
  58 /* ******************* */
  59 /* OSZAPC */
  60 /* ******************* */
  61
  62 /* size, carries, result */
  63 #define SET_FLAGS_OSZAPC_SIZE(size, lf_carries, lf_result) { \
  64     target_ulong temp = ((lf_carries) & (LF_MASK_AF)) | \
  65     (((lf_carries) >> (size - 2)) << LF_BIT_PO); \
  66     env->hvf_lflags.result = (target_ulong)(int##size##_t)(lf_result); \
  67     if ((size) == 32) { \
  68         temp = ((lf_carries) & ~(LF_MASK_PDB | LF_MASK_SD)); \
  69     } else if ((size) == 16) { \
  70         temp = ((lf_carries) & (LF_MASK_AF)) | ((lf_carries) << 16); \
  71     } else if ((size) == 8)  { \
  72         temp = ((lf_carries) & (LF_MASK_AF)) | ((lf_carries) << 24); \
  73     } else { \
  74         VM_PANIC("unimplemented");  \
  75     } \
  76     env->hvf_lflags.auxbits = (target_ulong)(uint32_t)temp; \
  77 }
  78
  79 /* carries, result */
  80 #define SET_FLAGS_OSZAPC_8(carries, result) \
  81     SET_FLAGS_OSZAPC_SIZE(8, carries, result)
  82 #define SET_FLAGS_OSZAPC_16(carries, result) \
  83     SET_FLAGS_OSZAPC_SIZE(16, carries, result)
  84 #define SET_FLAGS_OSZAPC_32(carries, result) \
  85     SET_FLAGS_OSZAPC_SIZE(32, carries, result)
  86
  87 /* ******************* */
  88 /* OSZAP */
  89 /* ******************* */
  90 /* size, carries, result */
  91 #define SET_FLAGS_OSZAP_SIZE(size, lf_carries, lf_result) { \
  92     target_ulong temp = ((lf_carries) & (LF_MASK_AF)) | \
  93     (((lf_carries) >> (size - 2)) << LF_BIT_PO); \
  94     if ((size) == 32) { \
  95         temp = ((lf_carries) & ~(LF_MASK_PDB | LF_MASK_SD)); \
  96     } else if ((size) == 16) { \
  97         temp = ((lf_carries) & (LF_MASK_AF)) | ((lf_carries) << 16); \
  98     } else if ((size) == 8) { \
  99         temp = ((lf_carries) & (LF_MASK_AF)) | ((lf_carries) << 24); \
 100     } else { \
 101         VM_PANIC("unimplemented");      \
 102     } \
 103     env->hvf_lflags.result = (target_ulong)(int##size##_t)(lf_result); \
 104     target_ulong delta_c = (env->hvf_lflags.auxbits ^ temp) & LF_MASK_CF; \
 105     delta_c ^= (delta_c >> 1); \
 106     env->hvf_lflags.auxbits = (target_ulong)(uint32_t)(temp ^ delta_c); \
 107 }
 108
 109 /* carries, result */
 110 #define SET_FLAGS_OSZAP_8(carries, result) \
 111     SET_FLAGS_OSZAP_SIZE(8, carries, result)
 112 #define SET_FLAGS_OSZAP_16(carries, result) \
 113     SET_FLAGS_OSZAP_SIZE(16, carries, result)
 114 #define SET_FLAGS_OSZAP_32(carries, result) \
 115     SET_FLAGS_OSZAP_SIZE(32, carries, result)
 116
 117 void SET_FLAGS_OxxxxC(CPUX86State *env, uint32_t new_of, uint32_t new_cf)
 118 {
 119     uint32_t temp_po = new_of ^ new_cf;
 120     env->hvf_lflags.auxbits &= ~(LF_MASK_PO | LF_MASK_CF);
 121     env->hvf_lflags.auxbits |= (temp_po << LF_BIT_PO) | (new_cf << LF_BIT_CF);
 122 }
 123
 124 void SET_FLAGS_OSZAPC_SUB32(CPUX86State *env, uint32_t v1, uint32_t v2,
 125                             uint32_t diff)
 126 {
 127     SET_FLAGS_OSZAPC_32(SUB_COUT_VEC(v1, v2, diff), diff);
 128 }
 129
 130 void SET_FLAGS_OSZAPC_SUB16(CPUX86State *env, uint16_t v1, uint16_t v2,
 131                             uint16_t diff)
 132 {
 133     SET_FLAGS_OSZAPC_16(SUB_COUT_VEC(v1, v2, diff), diff);
 134 }
 135
 136 void SET_FLAGS_OSZAPC_SUB8(CPUX86State *env, uint8_t v1, uint8_t v2,
 137                             uint8_t diff)
 138 {
 139     SET_FLAGS_OSZAPC_8(SUB_COUT_VEC(v1, v2, diff), diff);
 140 }
 141
 142 void SET_FLAGS_OSZAPC_ADD32(CPUX86State *env, uint32_t v1, uint32_t v2,
 143                             uint32_t diff)
 144 {
 145     SET_FLAGS_OSZAPC_32(ADD_COUT_VEC(v1, v2, diff), diff);
 146 }
 147
 148 void SET_FLAGS_OSZAPC_ADD16(CPUX86State *env, uint16_t v1, uint16_t v2,
 149                             uint16_t diff)
 150 {
 151     SET_FLAGS_OSZAPC_16(ADD_COUT_VEC(v1, v2, diff), diff);
 152 }
 153
 154 void SET_FLAGS_OSZAPC_ADD8(CPUX86State *env, uint8_t v1, uint8_t v2,
 155                             uint8_t diff)
 156 {
 157     SET_FLAGS_OSZAPC_8(ADD_COUT_VEC(v1, v2, diff), diff);
 158 }
 159
 160 void SET_FLAGS_OSZAP_SUB32(CPUX86State *env, uint32_t v1, uint32_t v2,
 161                             uint32_t diff)
 162 {
 163     SET_FLAGS_OSZAP_32(SUB_COUT_VEC(v1, v2, diff), diff);
 164 }
 165
 166 void SET_FLAGS_OSZAP_SUB16(CPUX86State *env, uint16_t v1, uint16_t v2,
 167                             uint16_t diff)
 168 {
 169     SET_FLAGS_OSZAP_16(SUB_COUT_VEC(v1, v2, diff), diff);
 170 }
 171
 172 void SET_FLAGS_OSZAP_SUB8(CPUX86State *env, uint8_t v1, uint8_t v2,
 173                             uint8_t diff)
 174 {
 175     SET_FLAGS_OSZAP_8(SUB_COUT_VEC(v1, v2, diff), diff);
 176 }
 177
 178 void SET_FLAGS_OSZAP_ADD32(CPUX86State *env, uint32_t v1, uint32_t v2,
 179                             uint32_t diff)
 180 {
 181     SET_FLAGS_OSZAP_32(ADD_COUT_VEC(v1, v2, diff), diff);
 182 }
 183
 184 void SET_FLAGS_OSZAP_ADD16(CPUX86State *env, uint16_t v1, uint16_t v2,
 185                             uint16_t diff)
 186 {
 187     SET_FLAGS_OSZAP_16(ADD_COUT_VEC(v1, v2, diff), diff);
 188 }
 189
 190 void SET_FLAGS_OSZAP_ADD8(CPUX86State *env, uint8_t v1, uint8_t v2,
 191                             uint8_t diff)
 192 {
 193     SET_FLAGS_OSZAP_8(ADD_COUT_VEC(v1, v2, diff), diff);
 194 }
 195
 196
 197 void SET_FLAGS_OSZAPC_LOGIC32(CPUX86State *env, uint32_t v1, uint32_t v2,
 198                               uint32_t diff)
 199 {
 200     SET_FLAGS_OSZAPC_32(0, diff);
 201 }
 202
 203 void SET_FLAGS_OSZAPC_LOGIC16(CPUX86State *env, uint16_t v1, uint16_t v2,
 204                               uint16_t diff)
 205 {
 206     SET_FLAGS_OSZAPC_16(0, diff);
 207 }
 208
 209 void SET_FLAGS_OSZAPC_LOGIC8(CPUX86State *env, uint8_t v1, uint8_t v2,
 210                              uint8_t diff)
 211 {
 212     SET_FLAGS_OSZAPC_8(0, diff);
 213 }
 214
 215 bool get_PF(CPUX86State *env)
 216 {
 217     uint32_t temp = (255 & env->hvf_lflags.result);
 218     temp = temp ^ (255 & (env->hvf_lflags.auxbits >> LF_BIT_PDB));
 219     temp = (temp ^ (temp >> 4)) & 0x0F;
 220     return (0x9669U >> temp) & 1;
 221 }
 222
 223 void set_PF(CPUX86State *env, bool val)
 224 {
 225     uint32_t temp = (255 & env->hvf_lflags.result) ^ (!val);
 226     env->hvf_lflags.auxbits &= ~(LF_MASK_PDB);
 227     env->hvf_lflags.auxbits |= (temp << LF_BIT_PDB);
 228 }
 229
 230 bool get_OF(CPUX86State *env)
 231 {
 232     return ((env->hvf_lflags.auxbits + (1U << LF_BIT_PO)) >> LF_BIT_CF) & 1;
 233 }
 234
 235 bool get_CF(CPUX86State *env)
 236 {
 237     return (env->hvf_lflags.auxbits >> LF_BIT_CF) & 1;
 238 }
 239
 240 void set_OF(CPUX86State *env, bool val)
 241 {
 242     bool old_cf = get_CF(env);
 243     SET_FLAGS_OxxxxC(env, val, old_cf);
 244 }
 245
 246 void set_CF(CPUX86State *env, bool val)
 247 {
 248     bool old_of = get_OF(env);
 249     SET_FLAGS_OxxxxC(env, old_of, val);
 250 }
 251
 252 bool get_AF(CPUX86State *env)
 253 {
 254     return (env->hvf_lflags.auxbits >> LF_BIT_AF) & 1;
 255 }
 256
 257 void set_AF(CPUX86State *env, bool val)
 258 {
 259     env->hvf_lflags.auxbits &= ~(LF_MASK_AF);
 260     env->hvf_lflags.auxbits |= val << LF_BIT_AF;
 261 }
 262
 263 bool get_ZF(CPUX86State *env)
 264 {
 265     return !env->hvf_lflags.result;
 266 }
 267
 268 void set_ZF(CPUX86State *env, bool val)
 269 {
 270     if (val) {
 271         env->hvf_lflags.auxbits ^=
 272          (((env->hvf_lflags.result >> LF_SIGN_BIT) & 1) << LF_BIT_SD);
 273         /* merge the parity bits into the Parity Delta Byte */
 274         uint32_t temp_pdb = (255 & env->hvf_lflags.result);
 275         env->hvf_lflags.auxbits ^= (temp_pdb << LF_BIT_PDB);
 276         /* now zero the .result value */
 277         env->hvf_lflags.result = 0;
 278     } else {
 279         env->hvf_lflags.result |= (1 << 8);
 280     }
 281 }
 282
 283 bool get_SF(CPUX86State *env)
 284 {
 285     return ((env->hvf_lflags.result >> LF_SIGN_BIT) ^
 286             (env->hvf_lflags.auxbits >> LF_BIT_SD)) & 1;
 287 }
 288
 289 void set_SF(CPUX86State *env, bool val)
 290 {
 291     bool temp_sf = get_SF(env);
 292     env->hvf_lflags.auxbits ^= (temp_sf ^ val) << LF_BIT_SD;
 293 }
 294
 295 void lflags_to_rflags(CPUX86State *env)
 296 {
 297     env->eflags |= get_CF(env) ? CC_C : 0;
 298     env->eflags |= get_PF(env) ? CC_P : 0;
 299     env->eflags |= get_AF(env) ? CC_A : 0;
 300     env->eflags |= get_ZF(env) ? CC_Z : 0;
 301     env->eflags |= get_SF(env) ? CC_S : 0;
 302     env->eflags |= get_OF(env) ? CC_O : 0;
 303 }
 304
 305 void rflags_to_lflags(CPUX86State *env)
 306 {
 307     env->hvf_lflags.auxbits = env->hvf_lflags.result = 0;
 308     set_OF(env, env->eflags & CC_O);
 309     set_SF(env, env->eflags & CC_S);
 310     set_ZF(env, env->eflags & CC_Z);
 311     set_AF(env, env->eflags & CC_A);
 312     set_PF(env, env->eflags & CC_P);
 313     set_CF(env, env->eflags & CC_C);
 314 }