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