xref: /openbmc/qemu/target/i386/hvf/x86_flags.c (revision 0f9668e0)
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