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
SET_FLAGS_OxxxxC(CPUX86State * env,uint32_t new_of,uint32_t new_cf)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
SET_FLAGS_OSZAPC_SUB32(CPUX86State * env,uint32_t v1,uint32_t v2,uint32_t diff)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
SET_FLAGS_OSZAPC_SUB16(CPUX86State * env,uint16_t v1,uint16_t v2,uint16_t diff)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
SET_FLAGS_OSZAPC_SUB8(CPUX86State * env,uint8_t v1,uint8_t v2,uint8_t diff)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
SET_FLAGS_OSZAPC_ADD32(CPUX86State * env,uint32_t v1,uint32_t v2,uint32_t diff)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
SET_FLAGS_OSZAPC_ADD16(CPUX86State * env,uint16_t v1,uint16_t v2,uint16_t diff)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
SET_FLAGS_OSZAPC_ADD8(CPUX86State * env,uint8_t v1,uint8_t v2,uint8_t diff)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
SET_FLAGS_OSZAP_SUB32(CPUX86State * env,uint32_t v1,uint32_t v2,uint32_t diff)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
SET_FLAGS_OSZAP_SUB16(CPUX86State * env,uint16_t v1,uint16_t v2,uint16_t diff)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
SET_FLAGS_OSZAP_SUB8(CPUX86State * env,uint8_t v1,uint8_t v2,uint8_t diff)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
SET_FLAGS_OSZAP_ADD32(CPUX86State * env,uint32_t v1,uint32_t v2,uint32_t diff)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
SET_FLAGS_OSZAP_ADD16(CPUX86State * env,uint16_t v1,uint16_t v2,uint16_t diff)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
SET_FLAGS_OSZAP_ADD8(CPUX86State * env,uint8_t v1,uint8_t v2,uint8_t diff)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
SET_FLAGS_OSZAPC_LOGIC32(CPUX86State * env,uint32_t v1,uint32_t v2,uint32_t diff)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
SET_FLAGS_OSZAPC_LOGIC16(CPUX86State * env,uint16_t v1,uint16_t v2,uint16_t diff)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
SET_FLAGS_OSZAPC_LOGIC8(CPUX86State * env,uint8_t v1,uint8_t v2,uint8_t diff)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
get_PF(CPUX86State * env)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
set_PF(CPUX86State * env,bool val)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
get_OF(CPUX86State * env)229 bool get_OF(CPUX86State *env)
230 {
231 return ((env->hvf_lflags.auxbits + (1U << LF_BIT_PO)) >> LF_BIT_CF) & 1;
232 }
233
get_CF(CPUX86State * env)234 bool get_CF(CPUX86State *env)
235 {
236 return (env->hvf_lflags.auxbits >> LF_BIT_CF) & 1;
237 }
238
set_OF(CPUX86State * env,bool val)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
set_CF(CPUX86State * env,bool val)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
get_AF(CPUX86State * env)251 bool get_AF(CPUX86State *env)
252 {
253 return (env->hvf_lflags.auxbits >> LF_BIT_AF) & 1;
254 }
255
set_AF(CPUX86State * env,bool val)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
get_ZF(CPUX86State * env)262 bool get_ZF(CPUX86State *env)
263 {
264 return !env->hvf_lflags.result;
265 }
266
set_ZF(CPUX86State * env,bool val)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
get_SF(CPUX86State * env)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
set_SF(CPUX86State * env,bool val)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
lflags_to_rflags(CPUX86State * env)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
rflags_to_lflags(CPUX86State * env)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 }
314