* Fast486 386/486 CPU Emulation Library
* fpu.c
*
- * Copyright (C) 2013 Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
+ * Copyright (C) 2014 Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
#include <fast486.h>
#include "common.h"
-#include "opcodes.h"
#include "fpu.h"
-/* PUBLIC FUNCTIONS ***********************************************************/
+/* PRIVATE FUNCTIONS **********************************************************/
-FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD8)
+static ULONGLONG
+UnsignedMult128(ULONGLONG Multiplicand,
+ ULONGLONG Multiplier,
+ ULONGLONG *HighProduct)
{
- FAST486_MOD_REG_RM ModRegRm;
- BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
+ ULONG MultiplicandLow, MultiplicandHigh, MultiplierLow, MultiplierHigh;
+ ULONG IntermediateLow, IntermediateHigh;
+ ULONGLONG LowProduct, Intermediate, Intermediate1, Intermediate2;
+
+ MultiplicandLow = (ULONG)(Multiplicand & 0xFFFFFFFFULL);
+ MultiplicandHigh = (ULONG)(Multiplicand >> 32);
+ MultiplierLow = (ULONG)(Multiplier & 0xFFFFFFFFULL);
+ MultiplierHigh = (ULONG)(Multiplier >> 32);
+
+ LowProduct = (ULONGLONG)MultiplicandLow * (ULONGLONG)MultiplierLow;
+ Intermediate1 = (ULONGLONG)MultiplicandLow * (ULONGLONG)MultiplierHigh;
+ Intermediate2 = (ULONGLONG)MultiplicandHigh * (ULONGLONG)MultiplierLow;
+ *HighProduct = (ULONGLONG)MultiplicandHigh * (ULONGLONG)MultiplierHigh;
+
+ Intermediate = Intermediate1 + Intermediate2;
+ if (Intermediate < Intermediate1) *HighProduct += 1ULL << 32;
+
+ IntermediateLow = (ULONG)(Intermediate & 0xFFFFFFFFULL);
+ IntermediateHigh = (ULONG)(Intermediate >> 32);
+
+ LowProduct += (ULONGLONG)IntermediateLow << 32;
+ if ((ULONG)(LowProduct >> 32) < IntermediateLow) (*HighProduct)++;
+
+ *HighProduct += IntermediateHigh;
+ return LowProduct;
+}
- /* Get the operands */
- if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
+static VOID
+Fast486FpuGetSingleReal(PFAST486_STATE State,
+ ULONG Value,
+ PFAST486_FPU_DATA_REG Result)
+{
+ /* Extract the sign, exponent and mantissa */
+ Result->Sign = (UCHAR)(Value >> 31);
+ Result->Exponent = (USHORT)((Value >> 23) & 0xFF);
+ Result->Mantissa = (((ULONGLONG)Value & 0x7FFFFFULL) | 0x800000ULL) << 40;
+
+ /* If this is a zero, we're done */
+ if (Value == 0) return;
+
+ if (Result->Exponent == 0xFF) Result->Exponent = FPU_MAX_EXPONENT + 1;
+ else
{
- /* Exception occurred */
- return FALSE;
+ /* Adjust the exponent bias */
+ Result->Exponent += (FPU_REAL10_BIAS - FPU_REAL4_BIAS);
}
+}
- FPU_CHECK();
+static VOID
+Fast486FpuGetDoubleReal(PFAST486_STATE State,
+ ULONGLONG Value,
+ PFAST486_FPU_DATA_REG Result)
+{
+ /* Extract the sign, exponent and mantissa */
+ Result->Sign = (UCHAR)(Value >> 63);
+ Result->Exponent = (USHORT)((Value >> 52) & 0x7FF);
+ Result->Mantissa = (((ULONGLONG)Value & 0xFFFFFFFFFFFFFULL) | 0x10000000000000ULL) << 11;
+
+ /* If this is a zero, we're done */
+ if (Value == 0) return;
+
+ if (Result->Exponent == 0x3FF) Result->Exponent = FPU_MAX_EXPONENT + 1;
+ else
+ {
+ /* Adjust the exponent bias */
+ Result->Exponent += (FPU_REAL10_BIAS - FPU_REAL8_BIAS);
+ }
+}
+
+static VOID
+Fast486FpuAdd(PFAST486_STATE State,
+ PFAST486_FPU_DATA_REG FirstOperand,
+ PFAST486_FPU_DATA_REG SecondOperand,
+ PFAST486_FPU_DATA_REG Result)
+{
+ FAST486_FPU_DATA_REG FirstAdjusted = *FirstOperand;
+ FAST486_FPU_DATA_REG SecondAdjusted = *SecondOperand;
+ FAST486_FPU_DATA_REG TempResult;
+
+ if (!FPU_IS_NORMALIZED(FirstOperand) || !FPU_IS_NORMALIZED(SecondOperand))
+ {
+ /* Denormalized */
+ State->FpuStatus.De = TRUE;
+ }
+
+ /* Find the largest exponent */
+ TempResult.Exponent = max(FirstOperand->Exponent, SecondOperand->Exponent);
+
+ /* Adjust the first operand to it... */
+ if (FirstAdjusted.Exponent < TempResult.Exponent)
+ {
+ FirstAdjusted.Mantissa >>= (TempResult.Exponent - FirstAdjusted.Exponent);
+ FirstAdjusted.Exponent = TempResult.Exponent;
+ }
+
+ /* ... and the second one too */
+ if (SecondAdjusted.Exponent < TempResult.Exponent)
+ {
+ SecondAdjusted.Mantissa >>= (TempResult.Exponent - SecondAdjusted.Exponent);
+ SecondAdjusted.Exponent = TempResult.Exponent;
+ }
+
+ if (FirstAdjusted.Sign == SecondAdjusted.Sign)
+ {
+ /* Calculate the mantissa and sign of the result */
+ TempResult.Mantissa = FirstAdjusted.Mantissa + SecondAdjusted.Mantissa;
+ TempResult.Sign = FirstAdjusted.Sign;
+ }
+ else
+ {
+ /* Calculate the sign of the result */
+ if (FirstAdjusted.Mantissa > SecondAdjusted.Mantissa) TempResult.Sign = FirstAdjusted.Sign;
+ else if (FirstAdjusted.Mantissa < SecondAdjusted.Mantissa) TempResult.Sign = SecondAdjusted.Sign;
+ else TempResult.Sign = FALSE;
+
+ /* Invert the negative mantissa */
+ if (FirstAdjusted.Sign) FirstAdjusted.Mantissa = -FirstAdjusted.Mantissa;
+ if (SecondAdjusted.Sign) SecondAdjusted.Mantissa = -SecondAdjusted.Mantissa;
+
+ /* Calculate the mantissa of the result */
+ TempResult.Mantissa = FirstAdjusted.Mantissa + SecondAdjusted.Mantissa;
+ }
+
+ /* Did it overflow? */
+ if (FPU_IS_NORMALIZED(&FirstAdjusted) && FPU_IS_NORMALIZED(&SecondAdjusted))
+ {
+ if (TempResult.Exponent == FPU_MAX_EXPONENT)
+ {
+ /* Total overflow, return infinity */
+ TempResult.Mantissa = FPU_MANTISSA_HIGH_BIT;
+ TempResult.Exponent = FPU_MAX_EXPONENT + 1;
+
+ /* Update flags */
+ State->FpuStatus.Oe = TRUE;
+ }
+ else
+ {
+ /* Lose the LSB in favor of the carry */
+ TempResult.Mantissa >>= 1;
+ TempResult.Mantissa |= FPU_MANTISSA_HIGH_BIT;
+ TempResult.Exponent++;
+ }
+ }
+
+ /* Normalize the result and return it */
+ Fast486FpuNormalize(State, &TempResult);
+ *Result = TempResult;
+}
+
+static VOID
+Fast486FpuSubtract(PFAST486_STATE State,
+ PFAST486_FPU_DATA_REG FirstOperand,
+ PFAST486_FPU_DATA_REG SecondOperand,
+ PFAST486_FPU_DATA_REG Result)
+{
+ FAST486_FPU_DATA_REG NegativeSecondOperand = *SecondOperand;
+
+ /* Invert the sign */
+ NegativeSecondOperand.Sign = !NegativeSecondOperand.Sign;
+
+ /* And perform an addition instead */
+ Fast486FpuAdd(State, Result, FirstOperand, &NegativeSecondOperand);
+}
+
+static VOID
+Fast486FpuCompare(PFAST486_STATE State,
+ PFAST486_FPU_DATA_REG FirstOperand,
+ PFAST486_FPU_DATA_REG SecondOperand)
+{
+ if (FPU_IS_NAN(FirstOperand) || FPU_IS_NAN(SecondOperand))
+ {
+ if (FPU_IS_POS_INF(FirstOperand) && FPU_IS_NEG_INF(SecondOperand))
+ {
+ State->FpuStatus.Code0 = FALSE;
+ State->FpuStatus.Code2 = FALSE;
+ State->FpuStatus.Code3 = FALSE;
+ }
+ else if (FPU_IS_NEG_INF(FirstOperand) && FPU_IS_POS_INF(SecondOperand))
+ {
+ State->FpuStatus.Code0 = TRUE;
+ State->FpuStatus.Code2 = FALSE;
+ State->FpuStatus.Code3 = FALSE;
+ }
+ else
+ {
+ State->FpuStatus.Code0 = TRUE;
+ State->FpuStatus.Code2 = TRUE;
+ State->FpuStatus.Code3 = TRUE;
+ }
+ }
+ else
+ {
+ FAST486_FPU_DATA_REG TempResult;
+
+ Fast486FpuSubtract(State, FirstOperand, SecondOperand, &TempResult);
+
+ if (FPU_IS_ZERO(&TempResult))
+ {
+ State->FpuStatus.Code0 = FALSE;
+ State->FpuStatus.Code2 = FALSE;
+ State->FpuStatus.Code3 = TRUE;
+ }
+ else if (TempResult.Sign)
+ {
+ State->FpuStatus.Code0 = TRUE;
+ State->FpuStatus.Code2 = FALSE;
+ State->FpuStatus.Code3 = FALSE;
+ }
+ else
+ {
+ State->FpuStatus.Code0 = FALSE;
+ State->FpuStatus.Code2 = FALSE;
+ State->FpuStatus.Code3 = FALSE;
+ }
+ }
+}
+
+static VOID
+Fast486FpuMultiply(PFAST486_STATE State,
+ PFAST486_FPU_DATA_REG FirstOperand,
+ PFAST486_FPU_DATA_REG SecondOperand,
+ PFAST486_FPU_DATA_REG Result)
+{
+ FAST486_FPU_DATA_REG TempResult;
+
+ if (!FPU_IS_NORMALIZED(FirstOperand) || !FPU_IS_NORMALIZED(SecondOperand))
+ {
+ /* Denormalized */
+ State->FpuStatus.De = TRUE;
+ }
+
+ UnsignedMult128(FirstOperand->Mantissa,
+ SecondOperand->Mantissa,
+ &TempResult.Mantissa);
+
+ TempResult.Exponent = FirstOperand->Exponent + SecondOperand->Exponent;
+ TempResult.Sign = FirstOperand->Sign ^ SecondOperand->Sign;
+
+ /* Normalize the result */
+ Fast486FpuNormalize(State, &TempResult);
+ *Result = TempResult;
+}
+
+static VOID
+Fast486FpuDivide(PFAST486_STATE State,
+ PFAST486_FPU_DATA_REG FirstOperand,
+ PFAST486_FPU_DATA_REG SecondOperand,
+ PFAST486_FPU_DATA_REG Result)
+{
+ FAST486_FPU_DATA_REG TempResult;
+
+ if (FPU_IS_ZERO(SecondOperand))
+ {
+ /* Division by zero */
+ State->FpuStatus.Ze = TRUE;
+ return;
+ }
+
+ TempResult.Exponent = FirstOperand->Exponent - SecondOperand->Exponent;
+ TempResult.Sign = FirstOperand->Sign ^ SecondOperand->Sign;
-#ifndef FAST486_NO_FPU
// TODO: NOT IMPLEMENTED
+ UNREFERENCED_PARAMETER(TempResult);
UNIMPLEMENTED;
-
- return FALSE;
-#else
- /* Do nothing */
- return TRUE;
-#endif
}
-FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD9)
+/* PUBLIC FUNCTIONS ***********************************************************/
+
+FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD8DC)
{
FAST486_MOD_REG_RM ModRegRm;
BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
+ PFAST486_FPU_DATA_REG SourceOperand, DestOperand;
+ FAST486_FPU_DATA_REG MemoryData;
/* Get the operands */
if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
FPU_CHECK();
#ifndef FAST486_NO_FPU
- // TODO: NOT IMPLEMENTED
- UNIMPLEMENTED;
- return FALSE;
-#else
- /* Do nothing */
- return TRUE;
+ if (ModRegRm.Memory)
+ {
+ /* Load the source operand from memory */
+
+ if (Opcode == 0xDC)
+ {
+ ULONGLONG Value;
+
+ if (!Fast486ReadMemory(State,
+ (State->PrefixFlags & FAST486_PREFIX_SEG)
+ ? State->SegmentOverride : FAST486_REG_DS,
+ ModRegRm.MemoryAddress,
+ FALSE,
+ &Value,
+ sizeof(ULONGLONG)))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ Fast486FpuGetDoubleReal(State, Value, &MemoryData);
+ }
+ else
+ {
+ ULONG Value;
+
+ if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ Fast486FpuGetSingleReal(State, Value, &MemoryData);
+ }
+
+ SourceOperand = &MemoryData;
+ }
+ else
+ {
+ /* Load the source operand from an FPU register */
+ SourceOperand = &FPU_ST(ModRegRm.SecondRegister);
+
+ if (FPU_GET_TAG(ModRegRm.SecondRegister) == FPU_TAG_EMPTY)
+ {
+ /* Invalid operation */
+ State->FpuStatus.Ie = TRUE;
+ return FALSE;
+ }
+ }
+
+ /* The destination operand is always ST0 */
+ DestOperand = &FPU_ST(0);
+
+ if (FPU_GET_TAG(0) == FPU_TAG_EMPTY)
+ {
+ /* Invalid operation */
+ State->FpuStatus.Ie = TRUE;
+ return FALSE;
+ }
+
+ /* Check the operation */
+ switch (ModRegRm.Register)
+ {
+ /* FADD */
+ case 0:
+ {
+ Fast486FpuAdd(State, DestOperand, SourceOperand, DestOperand);
+ break;
+ }
+
+ /* FMUL */
+ case 1:
+ {
+ Fast486FpuMultiply(State, DestOperand, SourceOperand, DestOperand);
+ break;
+ }
+
+ /* FCOM */
+ case 2:
+ /* FCOMP */
+ case 3:
+ {
+ Fast486FpuCompare(State, DestOperand, SourceOperand);
+ if (ModRegRm.Register == 3) Fast486FpuPop(State);
+
+ break;
+ }
+
+ /* FSUB */
+ case 4:
+ {
+ Fast486FpuSubtract(State, DestOperand, SourceOperand, DestOperand);
+ break;
+ }
+
+ /* FSUBR */
+ case 5:
+ {
+ Fast486FpuSubtract(State, SourceOperand, DestOperand, DestOperand);
+ break;
+ }
+
+ /* FDIV */
+ case 6:
+ {
+ Fast486FpuDivide(State, DestOperand, SourceOperand, DestOperand);
+ break;
+ }
+
+ /* FDIVR */
+ case 7:
+ {
+ Fast486FpuDivide(State, SourceOperand, DestOperand, DestOperand);
+ break;
+ }
+ }
+
#endif
+
+ return TRUE;
}
-FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDA)
+FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD9)
{
FAST486_MOD_REG_RM ModRegRm;
BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
#endif
}
-FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDB)
+FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDA)
{
FAST486_MOD_REG_RM ModRegRm;
BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
#endif
}
-FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDC)
+FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDB)
{
FAST486_MOD_REG_RM ModRegRm;
BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
FPU_CHECK();
#ifndef FAST486_NO_FPU
- // TODO: NOT IMPLEMENTED
- UNIMPLEMENTED;
- return FALSE;
-#else
- /* Do nothing */
- return TRUE;
+ if (ModRegRm.Memory)
+ {
+ // TODO: NOT IMPLEMENTED
+ UNIMPLEMENTED;
+ }
+ else
+ {
+ /* Only a few of these instructions have any meaning on a 487 */
+ switch ((ModRegRm.Register << 3) | ModRegRm.SecondRegister)
+ {
+ /* FCLEX */
+ case 0x22:
+ {
+ /* Clear exception data */
+ State->FpuStatus.Ie =
+ State->FpuStatus.De =
+ State->FpuStatus.Ze =
+ State->FpuStatus.Oe =
+ State->FpuStatus.Ue =
+ State->FpuStatus.Pe =
+ State->FpuStatus.Sf =
+ State->FpuStatus.Es =
+ State->FpuStatus.Busy = FALSE;
+
+ break;
+ }
+
+ /* FINIT */
+ case 0x23:
+ {
+ /* Restore the state */
+ State->FpuControl.Value = FAST486_FPU_DEFAULT_CONTROL;
+ State->FpuStatus.Value = 0;
+ State->FpuTag = 0xFFFF;
+
+ break;
+ }
+
+ /* FENI */
+ case 0x20:
+ /* FDISI */
+ case 0x21:
+ {
+ /* These do nothing */
+ break;
+ }
+
+ /* Invalid */
+ default:
+ {
+ Fast486Exception(State, FAST486_EXCEPTION_UD);
+ return FALSE;
+ }
+ }
+ }
+
#endif
+
+ return TRUE;
}
FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDD)
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