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 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_emul->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_emul->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_emul->lflags.result = (target_ulong)(int##size##_t)(lf_result); \
 104     target_ulong delta_c = (env->hvf_emul->lflags.auxbits ^ temp) & LF_MASK_CF; \
 105     delta_c ^= (delta_c >> 1); \
 106     env->hvf_emul->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_emul->lflags.auxbits &= ~(LF_MASK_PO | LF_MASK_CF);
 121     env->hvf_emul->lflags.auxbits |= (temp_po << LF_BIT_PO) |
 122                                      (new_cf << LF_BIT_CF);
 123 }
 124
 125 void SET_FLAGS_OSZAPC_SUB32(CPUX86State *env, uint32_t v1, uint32_t v2,
 126                             uint32_t diff)
 127 {
 128     SET_FLAGS_OSZAPC_32(SUB_COUT_VEC(v1, v2, diff), diff);
 129 }
 130
 131 void SET_FLAGS_OSZAPC_SUB16(CPUX86State *env, uint16_t v1, uint16_t v2,
 132                             uint16_t diff)
 133 {
 134     SET_FLAGS_OSZAPC_16(SUB_COUT_VEC(v1, v2, diff), diff);
 135 }
 136
 137 void SET_FLAGS_OSZAPC_SUB8(CPUX86State *env, uint8_t v1, uint8_t v2,
 138                             uint8_t diff)
 139 {
 140     SET_FLAGS_OSZAPC_8(SUB_COUT_VEC(v1, v2, diff), diff);
 141 }
 142
 143 void SET_FLAGS_OSZAPC_ADD32(CPUX86State *env, uint32_t v1, uint32_t v2,
 144                             uint32_t diff)
 145 {
 146     SET_FLAGS_OSZAPC_32(ADD_COUT_VEC(v1, v2, diff), diff);
 147 }
 148
 149 void SET_FLAGS_OSZAPC_ADD16(CPUX86State *env, uint16_t v1, uint16_t v2,
 150                             uint16_t diff)
 151 {
 152     SET_FLAGS_OSZAPC_16(ADD_COUT_VEC(v1, v2, diff), diff);
 153 }
 154
 155 void SET_FLAGS_OSZAPC_ADD8(CPUX86State *env, uint8_t v1, uint8_t v2,
 156                             uint8_t diff)
 157 {
 158     SET_FLAGS_OSZAPC_8(ADD_COUT_VEC(v1, v2, diff), diff);
 159 }
 160
 161 void SET_FLAGS_OSZAP_SUB32(CPUX86State *env, uint32_t v1, uint32_t v2,
 162                             uint32_t diff)
 163 {
 164     SET_FLAGS_OSZAP_32(SUB_COUT_VEC(v1, v2, diff), diff);
 165 }
 166
 167 void SET_FLAGS_OSZAP_SUB16(CPUX86State *env, uint16_t v1, uint16_t v2,
 168                             uint16_t diff)
 169 {
 170     SET_FLAGS_OSZAP_16(SUB_COUT_VEC(v1, v2, diff), diff);
 171 }
 172
 173 void SET_FLAGS_OSZAP_SUB8(CPUX86State *env, uint8_t v1, uint8_t v2,
 174                             uint8_t diff)
 175 {
 176     SET_FLAGS_OSZAP_8(SUB_COUT_VEC(v1, v2, diff), diff);
 177 }
 178
 179 void SET_FLAGS_OSZAP_ADD32(CPUX86State *env, uint32_t v1, uint32_t v2,
 180                             uint32_t diff)
 181 {
 182     SET_FLAGS_OSZAP_32(ADD_COUT_VEC(v1, v2, diff), diff);
 183 }
 184
 185 void SET_FLAGS_OSZAP_ADD16(CPUX86State *env, uint16_t v1, uint16_t v2,
 186                             uint16_t diff)
 187 {
 188     SET_FLAGS_OSZAP_16(ADD_COUT_VEC(v1, v2, diff), diff);
 189 }
 190
 191 void SET_FLAGS_OSZAP_ADD8(CPUX86State *env, uint8_t v1, uint8_t v2,
 192                             uint8_t diff)
 193 {
 194     SET_FLAGS_OSZAP_8(ADD_COUT_VEC(v1, v2, diff), diff);
 195 }
 196
 197
 198 void SET_FLAGS_OSZAPC_LOGIC32(CPUX86State *env, uint32_t v1, uint32_t v2,
 199                               uint32_t diff)
 200 {
 201     SET_FLAGS_OSZAPC_32(0, diff);
 202 }
 203
 204 void SET_FLAGS_OSZAPC_LOGIC16(CPUX86State *env, uint16_t v1, uint16_t v2,
 205                               uint16_t diff)
 206 {
 207     SET_FLAGS_OSZAPC_16(0, diff);
 208 }
 209
 210 void SET_FLAGS_OSZAPC_LOGIC8(CPUX86State *env, uint8_t v1, uint8_t v2,
 211                              uint8_t diff)
 212 {
 213     SET_FLAGS_OSZAPC_8(0, diff);
 214 }
 215
 216 bool get_PF(CPUX86State *env)
 217 {
 218     uint32_t temp = (255 & env->hvf_emul->lflags.result);
 219     temp = temp ^ (255 & (env->hvf_emul->lflags.auxbits >> LF_BIT_PDB));
 220     temp = (temp ^ (temp >> 4)) & 0x0F;
 221     return (0x9669U >> temp) & 1;
 222 }
 223
 224 void set_PF(CPUX86State *env, bool val)
 225 {
 226     uint32_t temp = (255 & env->hvf_emul->lflags.result) ^ (!val);
 227     env->hvf_emul->lflags.auxbits &= ~(LF_MASK_PDB);
 228     env->hvf_emul->lflags.auxbits |= (temp << LF_BIT_PDB);
 229 }
 230
 231 bool get_OF(CPUX86State *env)
 232 {
 233     return ((env->hvf_emul->lflags.auxbits + (1U << LF_BIT_PO)) >> LF_BIT_CF) & 1;
 234 }
 235
 236 bool get_CF(CPUX86State *env)
 237 {
 238     return (env->hvf_emul->lflags.auxbits >> LF_BIT_CF) & 1;
 239 }
 240
 241 void set_OF(CPUX86State *env, bool val)
 242 {
 243     bool old_cf = get_CF(env);
 244     SET_FLAGS_OxxxxC(env, val, old_cf);
 245 }
 246
 247 void set_CF(CPUX86State *env, bool val)
 248 {
 249     bool old_of = get_OF(env);
 250     SET_FLAGS_OxxxxC(env, old_of, val);
 251 }
 252
 253 bool get_AF(CPUX86State *env)
 254 {
 255     return (env->hvf_emul->lflags.auxbits >> LF_BIT_AF) & 1;
 256 }
 257
 258 void set_AF(CPUX86State *env, bool val)
 259 {
 260     env->hvf_emul->lflags.auxbits &= ~(LF_MASK_AF);
 261     env->hvf_emul->lflags.auxbits |= val << LF_BIT_AF;
 262 }
 263
 264 bool get_ZF(CPUX86State *env)
 265 {
 266     return !env->hvf_emul->lflags.result;
 267 }
 268
 269 void set_ZF(CPUX86State *env, bool val)
 270 {
 271     if (val) {
 272         env->hvf_emul->lflags.auxbits ^=
 273          (((env->hvf_emul->lflags.result >> LF_SIGN_BIT) & 1) << LF_BIT_SD);
 274         /* merge the parity bits into the Parity Delta Byte */
 275         uint32_t temp_pdb = (255 & env->hvf_emul->lflags.result);
 276         env->hvf_emul->lflags.auxbits ^= (temp_pdb << LF_BIT_PDB);
 277         /* now zero the .result value */
 278         env->hvf_emul->lflags.result = 0;
 279     } else {
 280         env->hvf_emul->lflags.result |= (1 << 8);
 281     }
 282 }
 283
 284 bool get_SF(CPUX86State *env)
 285 {
 286     return ((env->hvf_emul->lflags.result >> LF_SIGN_BIT) ^
 287             (env->hvf_emul->lflags.auxbits >> LF_BIT_SD)) & 1;
 288 }
 289
 290 void set_SF(CPUX86State *env, bool val)
 291 {
 292     bool temp_sf = get_SF(env);
 293     env->hvf_emul->lflags.auxbits ^= (temp_sf ^ val) << LF_BIT_SD;
 294 }
 295
 296 void lflags_to_rflags(CPUX86State *env)
 297 {
 298     env->hvf_emul->rflags.cf = get_CF(env);
 299     env->hvf_emul->rflags.pf = get_PF(env);
 300     env->hvf_emul->rflags.af = get_AF(env);
 301     env->hvf_emul->rflags.zf = get_ZF(env);
 302     env->hvf_emul->rflags.sf = get_SF(env);
 303     env->hvf_emul->rflags.of = get_OF(env);
 304 }
 305
 306 void rflags_to_lflags(CPUX86State *env)
 307 {
 308     env->hvf_emul->lflags.auxbits = env->hvf_emul->lflags.result = 0;
 309     set_OF(env, env->hvf_emul->rflags.of);
 310     set_SF(env, env->hvf_emul->rflags.sf);
 311     set_ZF(env, env->hvf_emul->rflags.zf);
 312     set_AF(env, env->hvf_emul->rflags.af);
 313     set_PF(env, env->hvf_emul->rflags.pf);
 314     set_CF(env, env->hvf_emul->rflags.cf);
 315 }