decode.c

简单的虚拟机

			/* string operations */
		case 0xA4: case 0xA5: case 0xA6: case 0xA7:
		case 0xAA: case 0xAB: case 0xAC: case 0xAD: case 0xAE: case 0xAF:
			Instruction.Opcode = *currentCode;
			Instruction.wFlag = *currentCode & 1;

			//sprintf(prefix, "%s", Instruction.RepeatPrefix > 0 ? RepeatPrefixes[(int)Instruction.RepeatPrefix] : "");
			//sprintf(mnemonic, "%s%c", StrMnemonic[(*currentCode >> 1) & 7], Instruction.wFlag ? 
			//		(Instruction.OperandPrefix >= 0 ? 'w' : 'd') : 'b');
			currentCode++;
			cpu.ip++;
			break;

			/* test */
		case 0xA8: case 0xA9:
			Instruction.Opcode = *currentCode;
			Instruction.wFlag = *currentCode & 1;
			Instruction.sFlag = !(*currentCode & 1);
			//sprintf(mnemonic, "%s", "test");
			//sprintf(operand1, "%s", Instruction.wFlag ? (!(Instruction.OperandPrefix >= 0) ? "ax" : "eax") : "al");
			currentCode++;
			cpu.ip++;
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			break;

			/* logical shift:rol ror rcl rcr shl shr sal sar */
		case 0xC0: case 0xC1:
			Instruction.Opcode = *currentCode;
			Instruction.wFlag = *currentCode & 1;
			Instruction.sFlag = 1;

			currentCode++;
			cpu.ip++;
			op=(*currentCode >> 3) & 7;
			////sprintf(mnemonic, "%s", LogicalShiftMnemonic[(*currentCode >> 3) & 7]);
			currentCode = ParseModRM(currentCode, &Instruction, &operand1);
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			//LG_SHIFT(LogicalShiftMnemonic[(*currentCode >> 3) & 7],operand1,operand2);
			switch(op)
			{
				case 0:handle_logicalshift(rol,operand1,immediate,Instruction.wFlag);break;
				case 1:handle_logicalshift(ror,operand1,immediate,Instruction.wFlag);break;
				case 2:handle_logicalshift(rcl,operand1,immediate,Instruction.wFlag);break;
				case 3:handle_logicalshift(rcr,operand1,immediate,Instruction.wFlag);break;
				case 4:handle_logicalshift(shl,operand1,immediate,Instruction.wFlag);break;
				case 5:handle_logicalshift(shr,operand1,immediate,Instruction.wFlag);break;
				case 6:handle_logicalshift(sal,operand1,immediate,Instruction.wFlag);break;
				case 7:handle_logicalshift(sar,operand1,immediate,Instruction.wFlag);break;
			}
			break;

		case 0xD0: case 0xD1:
			Instruction.Opcode  = *currentCode;
			Instruction.wFlag = *currentCode & 1;
			currentCode++;
			cpu.ip++;
			op=(*currentCode >> 3) & 7;
			currentCode = ParseModRM(currentCode, &Instruction, &operand1);
			/* operand2 = 1 */
			switch(op)
			{
				case 0:handle_logicalshift(rol,operand1,1,Instruction.wFlag);break;
				case 1:handle_logicalshift(ror,operand1,1,Instruction.wFlag);break;
				case 2:handle_logicalshift(rcl,operand1,1,Instruction.wFlag);break;
				case 3:handle_logicalshift(rcr,operand1,1,Instruction.wFlag);break;
				case 4:handle_logicalshift(shl,operand1,1,Instruction.wFlag);break;
				case 5:handle_logicalshift(shr,operand1,1,Instruction.wFlag);break;
				case 6:handle_logicalshift(sal,operand1,1,Instruction.wFlag);break;
				case 7:handle_logicalshift(sar,operand1,1,Instruction.wFlag);break;
			}
			break;
		case 0xD2: case 0xD3:
			Instruction.Opcode  = *currentCode;
			Instruction.wFlag = *currentCode & 1;
			currentCode++;
			cpu.ip++;
			op=(*currentCode >> 3) & 7;
			currentCode = ParseModRM(currentCode, &Instruction, &operand1);
			/* operand2 = cl */
			switch(op)
			{
				case 0:handle_logicalshift(rol,operand1,*greg8_addr(1),Instruction.wFlag);break;
				case 1:handle_logicalshift(ror,operand1,*greg8_addr(1),Instruction.wFlag);break;
				case 2:handle_logicalshift(rcl,operand1,*greg8_addr(1),Instruction.wFlag);break;
				case 3:handle_logicalshift(rcr,operand1,*greg8_addr(1),Instruction.wFlag);break;
				case 4:handle_logicalshift(shl,operand1,*greg8_addr(1),Instruction.wFlag);break;
				case 5:handle_logicalshift(shr,operand1,*greg8_addr(1),Instruction.wFlag);break;
				case 6:handle_logicalshift(sal,operand1,*greg8_addr(1),Instruction.wFlag);break;
				case 7:handle_logicalshift(sar,operand1,*greg8_addr(1),Instruction.wFlag);break;
			}
			break;

			/* retn */
		case 0xC2 :
			Instruction.Opcode = *currentCode;
			Instruction.sFlag = 0;
			Instruction.OperandPrefix = -1;
			currentCode++;
			cpu.ip++;
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			handle_pop16(cpu.ip);
			cpu.greg.sp+=immediate;
			break;
		case 0xC3:
			Instruction.Opcode = *currentCode;
			currentCode++;
			cpu.ip++;
			handle_pop16(cpu.ip);
			break;

			/* les, lds */
		case 0xC4: /*les*/
			Instruction.Opcode = *currentCode;
			Instruction.wFlag = 1;
			Instruction.dFlag = 1;
			currentCode++;
			cpu.ip++;
			currentCode = ParseRegModRM(currentCode, &Instruction, &operand1, &operand2);
			*(word*)operand1.value = *(word*)(cpu.ram+operand2.value);
			cpu.sreg.es = *(word*)(cpu.ram+operand2.value+2);
			break;
		case 0xC5: /*lds*/
			Instruction.Opcode = *currentCode;
			Instruction.wFlag = 1;
			Instruction.dFlag = 1;
			currentCode++;
			cpu.ip++;
			currentCode = ParseRegModRM(currentCode, &Instruction, &operand1, &operand2);
			*(word*)operand1.value = *(word*)(cpu.ram+operand2.value);
			cpu.sreg.ds = *(word*)(cpu.ram+operand2.value+2);
			break;
		case 0xC6: case 0xC7: /*mov*/
			Instruction.Opcode = *currentCode;
			Instruction.wFlag = *currentCode & 1;
			Instruction.sFlag = ((*currentCode & 1) ^ 1) & 1;
			currentCode++;
			cpu.ip++;
			currentCode = ParseModRM(currentCode, &Instruction, &operand1);
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			set_op_val(operand1,immediate);
			break;

			/* enter leave */
		case 0xC8: /*enter*/
			Instruction.Opcode = *currentCode;
			Instruction.sFlag = 0;
			Instruction.OperandPrefix = 0;
			currentCode++;
			cpu.ip++;
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			Instruction.sFlag = 1;
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			break;
		case 0xC9: /*leave*/
			Instruction.Opcode = *currentCode;
			//sprintf(mnemonic, "leave");
			currentCode++;
			cpu.ip++;
			break;

			/* retx */
		case 0xCA: /* retf imm */
			Instruction.Opcode = *currentCode;
			Instruction.sFlag = 0;
			Instruction.OperandPrefix = 0;
			currentCode++;
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			handle_pop16(cpu.ip);
			handle_pop16(cpu.sreg.cs);
			cpu.greg.sp+=immediate;

			break;
		case 0xCB: /* retf */
			Instruction.Opcode = *currentCode;
			currentCode++;
			handle_pop16(cpu.ip);
			handle_pop16(cpu.sreg.cs);
			break;

			/* int */
		case 0xCC:
			Instruction.Opcode = *currentCode;
			//sprintf(mnemonic, "int3");
			currentCode++;
			cpu.ip++;
			break;
		case 0xCD:
			Instruction.Opcode = *currentCode;
			Instruction.sFlag = 1;
			//sprintf(mnemonic, "int");
			currentCode++;
			cpu.ip++;
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			switch(immediate)
			{
				case 0x21:
					handle_int21();
					break;
				case 0x20:
					handle_int20();
					break;
				default:
					break;
			} 
			break;
		case 0xCE:
			Instruction.Opcode = *currentCode;
			//sprintf(mnemonic, "into");
			currentCode++;
			cpu.ip++;
			break;

		case 0xCF:
			Instruction.Opcode = *currentCode;
			//sprintf(mnemonic, "%s%c", "iret", Instruction.OperandPrefix >= 0 ? 'w' : 'd');
			currentCode++;
			cpu.ip++;
			break;

			/* aam aad */
		case 0xD4: case 0xD5:
			Instruction.Opcode = *currentCode;
			Instruction.sFlag = 1;
			//sprintf(mnemonic, BCDAdjustMnemonic[*currentCode & 7]);
			currentCode++;
			cpu.ip++;
			op=Instruction.Opcode & 7;
			if(*currentCode == 0x0A)
			{
				currentCode++;
				cpu.ip++;
			}
			else
			{
				currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
				switch(op)
				{case 4:handle_bcdadjust(aam);break;
					case 5:handle_bcdadjust(aad);break;
				}
			}
			break;

			/* setalc */
		case 0xD6:
			Instruction.Opcode = *currentCode;

			////sprintf(mnemonic, "salc");
			cpu.ip++;
			currentCode++;
			break;
		case 0xD7:
			Instruction.Opcode = *currentCode;
			//sprintf(mnemonic, "xlat");
			////sprintf(operand1, "byte ptr %s%s[ebx + al]", Instruction.SegmentPrefix >= 0 ? 
			//		SegmentRegisters[(int)Instruction.SegmentPrefix] : "", Instruction.SegmentPrefix >= 0 ? ":" : "");
			if(Instruction.SegmentPrefix>=0)
				cpu.greg.ax &= (*(cpu.ram+(cpu.sreg.ds<<4) + cpu.greg.bx + (cpu.greg.ax&0x00FF)) | 0xFF00);
			else
				cpu.greg.ax &= (*(cpu.ram+cpu.greg.bx + (cpu.greg.ax&0x00FF)) | 0xFF00);
			currentCode++;
			cpu.ip++;
			break;

			/* loopxx */
		case 0xE0: case 0xE1: case 0xE2:
			Instruction.Opcode = *currentCode;
			currentCode++;
			cpu.ip++;
			cpu.greg.cx--;
			if(Instruction.Opcode==0xE0 && cpu.greg.cx!=0 && (cpu.flags&FLAG_Z)==0) /*loopnz*/
			{
				cpu.ip = Instruction.LinearAddress + *((char*)currentCode) + currentCode - Code + 1 - (cpu.sreg.cs<<4);
			}
			else if(Instruction.Opcode==0xE1 && cpu.greg.cx!=0 && (cpu.flags&FLAG_Z)!=0) /*loopz*/
			{
				cpu.ip = Instruction.LinearAddress + *((char*)currentCode) + currentCode - Code + 1- (cpu.sreg.cs<<4);
			}
			else if(Instruction.Opcode==0xE2 && cpu.greg.cx!=0) /*loop*/
			{
				cpu.ip = Instruction.LinearAddress + *((char*)currentCode) + currentCode - Code + 1- (cpu.sreg.cs<<4);
			}
			else
			{
				currentCode++;
				cpu.ip++;
			}
			break;
		case 0xE3: /*jcxz*/
			Instruction.Opcode = *currentCode;
			currentCode++;
			cpu.ip++;
			if(cpu.greg.cx==0)
			{
				cpu.ip = Instruction.LinearAddress + *((char*)currentCode) + currentCode - Code + 1- (cpu.sreg.cs<<4);
			}
			else
			{
				currentCode++;
				cpu.ip++;
			}
			break;

			/* in out */
		case 0xE4: case 0xE5: case 0xE6: case 0xE7:
			Instruction.Opcode = *currentCode;
			Instruction.dFlag = (*currentCode >> 1) & 1;
			Instruction.wFlag = *currentCode & 1;
			Instruction.sFlag = 1;

			currentCode++;
			cpu.ip++;
			//sprintf(mnemonic, "%s", Instruction.dFlag ? "out" : "in");
			//Instruction.dFlag ? &operand1 : &operand2
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			//sprintf(Instruction.dFlag ? operand2 : operand1, "%s", Instruction.wFlag ?
			//		(!(Instruction.OperandPrefix >= 0) ? "ax" : "eax") : "al");
			break;
		case 0xEC: case 0xED: case 0xEE: case 0xEF:
			Instruction.Opcode = *currentCode;
			Instruction.wFlag = *currentCode & 1;
			Instruction.dFlag = (*currentCode >> 1) & 1;
			//sprintf(mnemonic, "%s", Instruction.dFlag ? "out" : "in");
			//sprintf(Instruction.dFlag ? operand2 : operand1, "%s", Instruction.wFlag ?
			//		(!(Instruction.OperandPrefix >= 0) ? "ax" : "eax") : "al");
			//sprintf(Instruction.dFlag ? operand1 : operand2, "dx");
			currentCode++;
			cpu.ip++;
			break;
			/* call jmp*/
		case 0xE8:
			Instruction.Opcode = *currentCode;
			//Instruction.sFlag;
			//sprintf(mnemonic, "call");
			currentCode++;
			cpu.ip++;
			cpu.ip+=2;
			//push ip;
			handle_push16(cpu.ip);
			cpu.ip=Instruction.LinearAddress + *((int *)currentCode) + currentCode - Code + 2 -(cpu.sreg.cs<<4);
			break;
		case 0xE9:
			Instruction.Opcode = *currentCode;
			//Instruction.sFlag;
			//sprintf(mnemonic, "jmp");
			currentCode++;
			cpu.ip++;
			currentCode+=2;
			cpu.ip=Instruction.LinearAddress + *((word *)currentCode) + currentCode - Code + 2 -(cpu.sreg.cs<<4);
			break;
		case 0xEA:
			Instruction.Opcode = *currentCode;
			Instruction.sFlag = 0;
			//sprintf(mnemonic, "jmp");
			currentCode++;
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			cpu.ip=(immediate)&0xFFFF;
			Instruction.OperandPrefix = 0;
			currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			cpu.sreg.cs=(immediate)&0xFFFF;
			break;
		case 0xEB:
			Instruction.Opcode = *currentCode;
			Instruction.sFlag = 1;
			//sprintf(mnemonic, "jmp");
			currentCode++;
			cpu.ip++;
			//sprintf(operand1, "short %X", Instruction.LinearAddress + *currentCode + currentCode - Code + 1);
			cpu.ip=Instruction.LinearAddress + *currentCode + currentCode - Code + 1 - (cpu.sreg.cs<<4);
			currentCode++;
			break;

		case 0xF1:
			Instruction.Opcode = *currentCode;

			//sprintf(mnemonic, "int1");
			currentCode++;
			cpu.ip++;
			break;
			/* hlt */
		case 0xF4:
			Instruction.Opcode = *currentCode;
			hlt = true;
			currentCode++;
			cpu.ip++;
			break;
		case 0xF5: /* cmc */
			Instruction.Opcode = *currentCode;
			cpu.flags=(cpu.flags&FLAG_C)?(cpu.flags&(!FLAG_C)):(cpu.flags|FLAG_C);
			currentCode++;
			cpu.ip++;
			break;
		case 0xF6: case 0xF7:
			Instruction.Opcode = *currentCode;
			Instruction.wFlag = *currentCode & 1;
			Instruction.sFlag = (~(*currentCode & 1)) & 1;
			currentCode++;
			cpu.ip++;
			op = (*currentCode >> 3) & 7;
			//sprintf(mnemonic, "%s", LogicalArithmeticMnemonic[(*currentCode >> 3) & 7]);
			currentCode = ParseModRM(currentCode, &Instruction, &operand1);
			//if(strcmp(mnemonic, "test") == 0)
			//{
			//	currentCode = ParseImmediate(currentCode, &Instruction, &immediate);
			//}
			break;