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i86: Add 0x6x instruction shadows, used by DEC Rainbow MS-DOS 2.01. [R. Belmont, based on a patch by Bavarese]

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This commit is contained in:
R. Belmont 2014-05-10 19:22:59 +00:00
parent 45189af3c8
commit dcf31bcf36
1 changed files with 20 additions and 2 deletions
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22
src/emu/cpu/i86/i86.c
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@ -1137,68 +1137,86 @@ bool i8086_common_cpu_device::common_op(UINT8 op)
CLK(POP_R16);
break;
// 8086 'invalid opcodes', as documented at http://www.os2museum.com/wp/?p=2147
// 0x60 - 0x6f are an alias to 0x70 - 0x7f.
// These instructions are used in the boot sector for some versions of
// MS-DOS 2.01 (e.g. the DEC Rainbow version).
case 0x60:
case 0x70: // i_jo
JMP( OF);
break;
case 0x61:
case 0x71: // i_jno
JMP(!OF);
break;
case 0x62:
case 0x72: // i_jc
JMP( CF);
break;
case 0x63:
case 0x73: // i_jnc
JMP(!CF);
break;
case 0x64:
case 0x74: // i_jz
JMP( ZF);
break;
case 0x65:
case 0x75: // i_jnz
JMP(!ZF);
break;
case 0x66:
case 0x76: // i_jce
JMP(CF || ZF);
break;
case 0x67:
case 0x77: // i_jnce
JMP(!(CF || ZF));
break;
case 0x68:
case 0x78: // i_js
JMP( SF);
break;
case 0x69:
case 0x79: // i_jns
JMP(!SF);
break;
case 0x6a:
case 0x7a: // i_jp
JMP( PF);
break;
case 0x6b:
case 0x7b: // i_jnp
JMP(!PF);
break;
case 0x6c:
case 0x7c: // i_jl
JMP((SF!=OF)&&(!ZF));
break;
case 0x6d:
case 0x7d: // i_jnl
JMP((ZF)||(SF==OF));
break;
case 0x6e:
case 0x7e: // i_jle
JMP((ZF)||(SF!=OF));
break;
case 0x6f:
case 0x7f: // i_jnle
JMP((SF==OF)&&(!ZF));
break;