183 lines
3.9 KiB
C
183 lines
3.9 KiB
C
/*++
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Copyright (c) 1994 Microsoft Corporation
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Module Name:
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mulops.c
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Abstract:
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This module implements the code to emulate the div and idiv opcodes.
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Author:
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David N. Cutler (davec) 21-Sep-1994
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Environment:
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Kernel mode only.
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Revision History:
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--*/
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#include "nthal.h"
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#include "emulate.h"
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VOID
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XmDivOp (
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IN PRXM_CONTEXT P
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)
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/*++
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Routine Description:
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This function emulates an unsigned div opcode.
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Arguments:
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P - Supplies a pointer to the emulation context structure.
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Return Value:
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None.
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--*/
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{
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UNALIGNED ULONG *DstHigh;
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ULONG Dividend;
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ULONG Divisor;
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ULARGE_INTEGER Large;
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ULONG Quotient;
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ULONG Remainder;
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//
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// Divide the unsigned operands and store result.
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//
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Divisor = P->SrcValue.Long;
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if (Divisor == 0) {
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longjmp(&P->JumpBuffer[0], XM_DIVIDE_BY_ZERO);
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}
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if (P->DataType == BYTE_DATA) {
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Dividend = (ULONG)P->Gpr[AX].Xx;
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Quotient = Dividend / Divisor;
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Remainder = Dividend % Divisor;
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DstHigh = (UNALIGNED ULONG *)(&P->Gpr[AX].Xh);
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Dividend >>= 8;
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} else if (P->DataType == WORD_DATA) {
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Dividend = (P->Gpr[DX].Xx << 16) | P->Gpr[AX].Xx;
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Quotient = Dividend / Divisor;
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Remainder = Dividend % Divisor;
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DstHigh = (UNALIGNED ULONG *)(&P->Gpr[DX].Xx);
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Dividend >>= 16;
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} else {
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Dividend = P->Gpr[EDX].Exx;
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Large.HighPart = Dividend;
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Large.LowPart = P->Gpr[EAX].Exx;
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Quotient = (ULONG)(Large.QuadPart / (ULONGLONG)Divisor);
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Remainder = (ULONG)(Large.QuadPart % (ULONGLONG)Divisor);
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DstHigh = (UNALIGNED ULONG *)(&P->Gpr[EDX].Exx);
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}
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if (Dividend >= Divisor) {
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longjmp(&P->JumpBuffer[0], XM_DIVIDE_QUOTIENT_OVERFLOW);
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}
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XmStoreResult(P, Quotient);
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P->DstLong = DstHigh;
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XmStoreResult(P, Remainder);
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return;
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}
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VOID
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XmIdivOp (
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IN PRXM_CONTEXT P
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)
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/*++
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Routine Description:
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This function emulates a signed idiv opcode.
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Arguments:
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P - Supplies a pointer to the emulation context structure.
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Return Value:
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None.
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--*/
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{
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UNALIGNED ULONG *DstHigh;
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LONG Dividend;
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LONG Divisor;
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LARGE_INTEGER Large;
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LONG Quotient;
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LONG Remainder;
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LARGE_INTEGER Result;
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//
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// Divide the signed operands and store result.
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//
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if (P->SrcValue.Long == 0) {
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longjmp(&P->JumpBuffer[0], XM_DIVIDE_BY_ZERO);
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}
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if (P->DataType == BYTE_DATA) {
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Divisor = (LONG)((SCHAR)P->SrcValue.Byte);
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Dividend = (LONG)((SHORT)P->Gpr[AX].Xx);
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Quotient = Dividend / Divisor;
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Remainder = Dividend % Divisor;
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DstHigh = (UNALIGNED ULONG *)(&P->Gpr[AX].Xh);
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if ((Quotient >> 8) != ((Quotient << 24) >> 31)) {
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longjmp(&P->JumpBuffer[0], XM_DIVIDE_QUOTIENT_OVERFLOW);
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}
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Quotient &= 0xff;
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Remainder &= 0xff;
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} else if (P->DataType == WORD_DATA) {
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Divisor = (LONG)((SHORT)P->SrcValue.Word);
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Dividend = (LONG)((P->Gpr[DX].Xx << 16) | P->Gpr[AX].Xx);
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Quotient = Dividend / Divisor;
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Remainder = Dividend % Divisor;
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DstHigh = (UNALIGNED ULONG *)(&P->Gpr[DX].Xx);
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if ((Quotient >> 16) != ((Quotient << 16) >> 31)) {
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longjmp(&P->JumpBuffer[0], XM_DIVIDE_QUOTIENT_OVERFLOW);
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}
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Quotient &= 0xffff;
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Remainder &= 0xfff;
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} else {
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Divisor = (LONG)(P->SrcValue.Long);
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Large.HighPart = (LONG)P->Gpr[EDX].Exx;
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Large.LowPart = P->Gpr[EAX].Exx;
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Result.QuadPart = Large.QuadPart / (LONGLONG)Divisor;
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Quotient = Result.LowPart;
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Remainder = (LONG)(Large.QuadPart % (LONGLONG)Divisor);
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DstHigh = (UNALIGNED ULONG *)(&P->Gpr[EDX].Exx);
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if (Result.HighPart != ((LONG)Result.LowPart >> 31)) {
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longjmp(&P->JumpBuffer[0], XM_DIVIDE_QUOTIENT_OVERFLOW);
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}
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}
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XmStoreResult(P, Quotient);
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P->DstLong = DstHigh;
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XmStoreResult(P, Remainder);
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return;
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}
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