[aandrejevic] 59565: [NTVDM] Remove the old "INT 0xFF" hack and instead use an invalid opcode sequence for emulator operations. Fix the flags register update bug.
Author: aandrejevic Date: Tue Jul 23 19:31:00 2013 New Revision: 59565
URL: http://svn.reactos.org/svn/reactos?rev=59565&view=rev Log: [NTVDM] Remove the old "INT 0xFF" hack and instead use an invalid opcode sequence for emulator operations. Fix the flags register update bug.
Modified: branches/ntvdm/subsystems/ntvdm/bios.c branches/ntvdm/subsystems/ntvdm/emulator.c branches/ntvdm/subsystems/ntvdm/emulator.h
Modified: branches/ntvdm/subsystems/ntvdm/bios.c URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/bios.c?re... ============================================================================== --- branches/ntvdm/subsystems/ntvdm/bios.c [iso-8859-1] (original) +++ branches/ntvdm/subsystems/ntvdm/bios.c [iso-8859-1] Tue Jul 23 19:31:00 2013 @@ -374,20 +374,19 @@ IntVecTable[i * 2] = Offset; IntVecTable[i * 2 + 1] = BIOS_SEGMENT;
- if (i != SPECIAL_INT_NUM) - { - BiosCode[Offset++] = 0xFA; // cli - - BiosCode[Offset++] = 0x6A; // push i - BiosCode[Offset++] = (BYTE)i; - - BiosCode[Offset++] = 0xCD; // int SPECIAL_INT_NUM - BiosCode[Offset++] = SPECIAL_INT_NUM; - - BiosCode[Offset++] = 0x83; // add sp, 2 - BiosCode[Offset++] = 0xC4; - BiosCode[Offset++] = 0x02; - } + BiosCode[Offset++] = 0xFA; // cli + + BiosCode[Offset++] = 0x6A; // push i + BiosCode[Offset++] = (BYTE)i; + + BiosCode[Offset++] = LOBYTE(EMULATOR_BOP); // BOP sequence + BiosCode[Offset++] = HIBYTE(EMULATOR_BOP); + BiosCode[Offset++] = LOBYTE(EMULATOR_INT_BOP); + BiosCode[Offset++] = HIBYTE(EMULATOR_INT_BOP); + + BiosCode[Offset++] = 0x83; // add sp, 2 + BiosCode[Offset++] = 0xC4; + BiosCode[Offset++] = 0x02;
BiosCode[Offset++] = 0xCF; // iret }
Modified: branches/ntvdm/subsystems/ntvdm/emulator.c URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/emulator.... ============================================================================== --- branches/ntvdm/subsystems/ntvdm/emulator.c [iso-8859-1] (original) +++ branches/ntvdm/subsystems/ntvdm/emulator.c [iso-8859-1] Tue Jul 23 19:31:00 2013 @@ -165,34 +165,32 @@ } }
-static VOID EmulatorSoftwareInt(PVOID Context, BYTE Number) +static VOID EmulatorBop(WORD Code) { WORD StackSegment, StackPointer, CodeSegment, InstructionPointer; BYTE IntNum; - - /* Check if this is the special interrupt */ - if (Number == SPECIAL_INT_NUM) - { - /* Get the SS:SP */ -#ifndef NEW_EMULATOR - StackSegment = EmulatorContext.state->segment_reg[SX86_SREG_SS].val; - StackPointer = EmulatorContext.state->general_reg[SX86_REG_SP].val; -#else - StackSegment = EmulatorContext.Registers[EMULATOR_REG_SS].LowWord; - StackPointer = EmulatorContext.Registers[EMULATOR_REG_SP].LowWord; -#endif - + LPWORD Stack; + + /* Get the SS:SP */ +#ifndef NEW_EMULATOR + StackSegment = EmulatorContext.state->segment_reg[SX86_SREG_SS].val; + StackPointer = EmulatorContext.state->general_reg[SX86_REG_SP].val; +#else + StackSegment = EmulatorContext.Registers[EMULATOR_REG_SS].LowWord; + StackPointer = EmulatorContext.Registers[EMULATOR_REG_SP].LowWord; +#endif + + /* Get the stack */ + Stack = (LPWORD)((ULONG_PTR)BaseAddress + TO_LINEAR(StackSegment, StackPointer)); + + if (Code == EMULATOR_INT_BOP) + { /* Get the interrupt number */ - IntNum = *(LPBYTE)((ULONG_PTR)BaseAddress + TO_LINEAR(StackSegment, StackPointer)); - - /* Move the stack pointer forward one word to skip the interrupt number */ - StackPointer += sizeof(WORD); + IntNum = LOBYTE(Stack[0]);
/* Get the CS:IP */ - InstructionPointer = *(LPWORD)((ULONG_PTR)BaseAddress - + TO_LINEAR(StackSegment, StackPointer)); - CodeSegment = *(LPWORD)((ULONG_PTR)BaseAddress - + TO_LINEAR(StackSegment, StackPointer + sizeof(WORD))); + InstructionPointer = Stack[1]; + CodeSegment = Stack[2];
/* Check if this was an exception */ if (IntNum < 8) @@ -275,7 +273,19 @@ break; } } - } + + /* Update the flags on the stack */ +#ifndef NEW_EMULATOR + Stack[3] = EmulatorContext.state->reg_flags.val; +#else + Stack[3] = EmulatorContext.Flags.LowWord; +#endif + } +} + +static VOID EmulatorSoftwareInt(PVOID Context, BYTE Number) +{ + /* Do nothing */ }
static VOID EmulatorHardwareInt(PVOID Context, BYTE Number) @@ -445,14 +455,30 @@ #endif }
-VOID EmulatorStep() -{ +VOID EmulatorStep(VOID) +{ + LPWORD Instruction; + #ifndef NEW_EMULATOR /* Print the current position - useful for debugging */ DPRINT("Executing at CS:IP = %04X:%04X\n", EmulatorGetRegister(EMULATOR_REG_CS), EmulatorContext.state->reg_ip);
+ Instruction = (LPWORD)((ULONG_PTR)BaseAddress + + TO_LINEAR(EmulatorGetRegister(EMULATOR_REG_CS), + EmulatorContext.state->reg_ip)); + + /* Check for the BIOS operation (BOP) sequence */ + if (Instruction[0] == EMULATOR_BOP) + { + /* Skip the opcodes */ + EmulatorContext.state->reg_ip += 4; + + /* Call the BOP handler */ + EmulatorBop(Instruction[1]); + } + /* Call the softx86 API */ if (!softx86_step(&EmulatorContext)) { @@ -464,7 +490,7 @@ #endif }
-VOID EmulatorCleanup() +VOID EmulatorCleanup(VOID) { /* Free the memory allocated for the 16-bit address space */ if (BaseAddress != NULL) HeapFree(GetProcessHeap(), 0, BaseAddress);
Modified: branches/ntvdm/subsystems/ntvdm/emulator.h URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/emulator.... ============================================================================== --- branches/ntvdm/subsystems/ntvdm/emulator.h [iso-8859-1] (original) +++ branches/ntvdm/subsystems/ntvdm/emulator.h [iso-8859-1] Tue Jul 23 19:31:00 2013 @@ -70,7 +70,8 @@ #define EMULATOR_NUM_CONTROL_REGS 8 #define EMULATOR_NUM_DEBUG_REGS 8 #define MAX_GDT_ENTRIES 8192 -#define SPECIAL_INT_NUM 0xFF +#define EMULATOR_BOP 0xC4C4 +#define EMULATOR_INT_BOP 0xBEEF
enum {
-
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