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Implement 8086/80186 undocumented 0x8e behavior

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Allofich
2021-11-04 23:54:55 +09:00
parent 498fbbf3e3
commit 857818d740
2 changed files with 91 additions and 11 deletions
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3
CHANGELOG
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@@ -1,11 +1,12 @@
0.83.20
- Added code to INT 18h emulation (IBM PC mode) to
jump to ROM BASIC if the user provided an IBM
ROM BASIC image to load. (joncampbell123)
- Added dosbox.conf option to load a ROM image
containing IBM PC ROM BASIC, for disk images
and MS-DOS setups that need it. (joncampbell123)
- Put in undocumented behavior in opcode 0x8e for
8086 and 80186. (Allofich)
- Made 8086 treat opcodes C0,C1,C8,C9,F1 as aliases
of C2,C3,CA,CB,F0. (Allofich)
- Made 8086 treat opcodes 0x60-0x6F as aliases of

99
src/cpu/core_normal/prefix_none.h
View File

@@ -631,17 +631,96 @@
if (rm >= 0xc0 ) {GetEArw;val=*earw;}
else {GetEAa;val=LoadMw(eaa);}
switch (which) {
#if CPU_CORE <= CPU_ARCHTYPE_8086
case 0x01: /* MOV CS,Ew (8086 only) */
case 0x00: /* MOV ES,Ew */
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#if CPU_CORE == CPU_ARCHTYPE_8086
case 0x01: /* MOV CS,Ew (8086) */
CPU_Cycles++; //Always do another instruction
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#else
#if CPU_CORE == CPU_ARCHTYPE_286
case 0x01: /* MOV CS,Ew (186) */
if(CPU_ArchitectureType == CPU_ARCHTYPE_286) goto illegal_opcode;
CPU_Cycles++; //Always do another instruction
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#endif
#endif
case 0x02: /* MOV SS,Ew */
CPU_Cycles++; //Always do another instruction
case 0x03: /* MOV DS,Ew */
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#if CPU_CORE == CPU_ARCHTYPE_8086
case 0x04: /* Alias of MOV ES,Ew (8086) */
which = 0;
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#else
#if CPU_CORE == CPU_ARCHTYPE_286
case 0x04: /* Alias of MOV ES,Ew (186) */
if(CPU_ArchitectureType == CPU_ARCHTYPE_286) goto illegal_opcode;
which = 0;
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#else
case 0x04: /* MOV FS,Ew (386+) */
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#endif
#endif
#if CPU_CORE == CPU_ARCHTYPE_8086
case 0x05: /* Alias of MOV CS,Ew (8086) */
which = 1;
CPU_Cycles++; //Always do another instruction
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#else
#if CPU_CORE == CPU_ARCHTYPE_286
case 0x05: /* Alias of MOV CS,Ew (186) */
if(CPU_ArchitectureType == CPU_ARCHTYPE_286) goto illegal_opcode;
which = 1;
CPU_Cycles++; //Always do another instruction
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#else
case 0x05: /* MOV FS,Ew (386+) */
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#endif
#endif
#if CPU_CORE == CPU_ARCHTYPE_8086
case 0x06: /* Alias of MOV SS,Ew (8086) */
which = 2;
CPU_Cycles++; //Always do another instruction
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#else
#if CPU_CORE == CPU_ARCHTYPE_286
case 0x06: /* Alias of MOV SS,Ew (186) */
if(CPU_ArchitectureType == CPU_ARCHTYPE_286) goto illegal_opcode;
which = 2;
CPU_Cycles++; //Always do another instruction
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#endif
#endif
#if CPU_CORE == CPU_ARCHTYPE_8086
case 0x07: /* Alias of MOV DS,Ew (8086) */
which = 3;
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#else
#if CPU_CORE == CPU_ARCHTYPE_286
case 0x07: /* Alias of MOV DS,Ew (186) */
if(CPU_ArchitectureType == CPU_ARCHTYPE_286) goto illegal_opcode;
which = 3;
if(CPU_SetSegGeneral((SegNames)which, val)) RUNEXCEPTION();
break;
#endif
#endif
case 0x02: /* MOV SS,Ew */
CPU_Cycles++; //Always do another instruction
case 0x00: /* MOV ES,Ew */
case 0x03: /* MOV DS,Ew */
case 0x05: /* MOV GS,Ew */
case 0x04: /* MOV FS,Ew */
if (CPU_SetSegGeneral((SegNames)which,val)) RUNEXCEPTION();
break;
default:
goto illegal_opcode;
}