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| Current File : //sys/contrib/dev/acpica/utilities/utmath.c |
/*******************************************************************************
*
* Module Name: utmath - Integer math support routines
*
******************************************************************************/
/*
* Copyright (C) 2000 - 2011, Intel Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*/
#define __UTMATH_C__
#include <contrib/dev/acpica/include/acpi.h>
#include <contrib/dev/acpica/include/accommon.h>
#define _COMPONENT ACPI_UTILITIES
ACPI_MODULE_NAME ("utmath")
/*
* Optional support for 64-bit double-precision integer divide. This code
* is configurable and is implemented in order to support 32-bit kernel
* environments where a 64-bit double-precision math library is not available.
*
* Support for a more normal 64-bit divide/modulo (with check for a divide-
* by-zero) appears after this optional section of code.
*/
#ifndef ACPI_USE_NATIVE_DIVIDE
/* Structures used only for 64-bit divide */
typedef struct uint64_struct
{
UINT32 Lo;
UINT32 Hi;
} UINT64_STRUCT;
typedef union uint64_overlay
{
UINT64 Full;
UINT64_STRUCT Part;
} UINT64_OVERLAY;
/*******************************************************************************
*
* FUNCTION: AcpiUtShortDivide
*
* PARAMETERS: Dividend - 64-bit dividend
* Divisor - 32-bit divisor
* OutQuotient - Pointer to where the quotient is returned
* OutRemainder - Pointer to where the remainder is returned
*
* RETURN: Status (Checks for divide-by-zero)
*
* DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)
* divide and modulo. The result is a 64-bit quotient and a
* 32-bit remainder.
*
******************************************************************************/
ACPI_STATUS
AcpiUtShortDivide (
UINT64 Dividend,
UINT32 Divisor,
UINT64 *OutQuotient,
UINT32 *OutRemainder)
{
UINT64_OVERLAY DividendOvl;
UINT64_OVERLAY Quotient;
UINT32 Remainder32;
ACPI_FUNCTION_TRACE (UtShortDivide);
/* Always check for a zero divisor */
if (Divisor == 0)
{
ACPI_ERROR ((AE_INFO, "Divide by zero"));
return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
}
DividendOvl.Full = Dividend;
/*
* The quotient is 64 bits, the remainder is always 32 bits,
* and is generated by the second divide.
*/
ACPI_DIV_64_BY_32 (0, DividendOvl.Part.Hi, Divisor,
Quotient.Part.Hi, Remainder32);
ACPI_DIV_64_BY_32 (Remainder32, DividendOvl.Part.Lo, Divisor,
Quotient.Part.Lo, Remainder32);
/* Return only what was requested */
if (OutQuotient)
{
*OutQuotient = Quotient.Full;
}
if (OutRemainder)
{
*OutRemainder = Remainder32;
}
return_ACPI_STATUS (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: AcpiUtDivide
*
* PARAMETERS: InDividend - Dividend
* InDivisor - Divisor
* OutQuotient - Pointer to where the quotient is returned
* OutRemainder - Pointer to where the remainder is returned
*
* RETURN: Status (Checks for divide-by-zero)
*
* DESCRIPTION: Perform a divide and modulo.
*
******************************************************************************/
ACPI_STATUS
AcpiUtDivide (
UINT64 InDividend,
UINT64 InDivisor,
UINT64 *OutQuotient,
UINT64 *OutRemainder)
{
UINT64_OVERLAY Dividend;
UINT64_OVERLAY Divisor;
UINT64_OVERLAY Quotient;
UINT64_OVERLAY Remainder;
UINT64_OVERLAY NormalizedDividend;
UINT64_OVERLAY NormalizedDivisor;
UINT32 Partial1;
UINT64_OVERLAY Partial2;
UINT64_OVERLAY Partial3;
ACPI_FUNCTION_TRACE (UtDivide);
/* Always check for a zero divisor */
if (InDivisor == 0)
{
ACPI_ERROR ((AE_INFO, "Divide by zero"));
return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
}
Divisor.Full = InDivisor;
Dividend.Full = InDividend;
if (Divisor.Part.Hi == 0)
{
/*
* 1) Simplest case is where the divisor is 32 bits, we can
* just do two divides
*/
Remainder.Part.Hi = 0;
/*
* The quotient is 64 bits, the remainder is always 32 bits,
* and is generated by the second divide.
*/
ACPI_DIV_64_BY_32 (0, Dividend.Part.Hi, Divisor.Part.Lo,
Quotient.Part.Hi, Partial1);
ACPI_DIV_64_BY_32 (Partial1, Dividend.Part.Lo, Divisor.Part.Lo,
Quotient.Part.Lo, Remainder.Part.Lo);
}
else
{
/*
* 2) The general case where the divisor is a full 64 bits
* is more difficult
*/
Quotient.Part.Hi = 0;
NormalizedDividend = Dividend;
NormalizedDivisor = Divisor;
/* Normalize the operands (shift until the divisor is < 32 bits) */
do
{
ACPI_SHIFT_RIGHT_64 (NormalizedDivisor.Part.Hi,
NormalizedDivisor.Part.Lo);
ACPI_SHIFT_RIGHT_64 (NormalizedDividend.Part.Hi,
NormalizedDividend.Part.Lo);
} while (NormalizedDivisor.Part.Hi != 0);
/* Partial divide */
ACPI_DIV_64_BY_32 (NormalizedDividend.Part.Hi,
NormalizedDividend.Part.Lo,
NormalizedDivisor.Part.Lo,
Quotient.Part.Lo, Partial1);
/*
* The quotient is always 32 bits, and simply requires adjustment.
* The 64-bit remainder must be generated.
*/
Partial1 = Quotient.Part.Lo * Divisor.Part.Hi;
Partial2.Full = (UINT64) Quotient.Part.Lo * Divisor.Part.Lo;
Partial3.Full = (UINT64) Partial2.Part.Hi + Partial1;
Remainder.Part.Hi = Partial3.Part.Lo;
Remainder.Part.Lo = Partial2.Part.Lo;
if (Partial3.Part.Hi == 0)
{
if (Partial3.Part.Lo >= Dividend.Part.Hi)
{
if (Partial3.Part.Lo == Dividend.Part.Hi)
{
if (Partial2.Part.Lo > Dividend.Part.Lo)
{
Quotient.Part.Lo--;
Remainder.Full -= Divisor.Full;
}
}
else
{
Quotient.Part.Lo--;
Remainder.Full -= Divisor.Full;
}
}
Remainder.Full = Remainder.Full - Dividend.Full;
Remainder.Part.Hi = (UINT32) -((INT32) Remainder.Part.Hi);
Remainder.Part.Lo = (UINT32) -((INT32) Remainder.Part.Lo);
if (Remainder.Part.Lo)
{
Remainder.Part.Hi--;
}
}
}
/* Return only what was requested */
if (OutQuotient)
{
*OutQuotient = Quotient.Full;
}
if (OutRemainder)
{
*OutRemainder = Remainder.Full;
}
return_ACPI_STATUS (AE_OK);
}
#else
/*******************************************************************************
*
* FUNCTION: AcpiUtShortDivide, AcpiUtDivide
*
* PARAMETERS: See function headers above
*
* DESCRIPTION: Native versions of the UtDivide functions. Use these if either
* 1) The target is a 64-bit platform and therefore 64-bit
* integer math is supported directly by the machine.
* 2) The target is a 32-bit or 16-bit platform, and the
* double-precision integer math library is available to
* perform the divide.
*
******************************************************************************/
ACPI_STATUS
AcpiUtShortDivide (
UINT64 InDividend,
UINT32 Divisor,
UINT64 *OutQuotient,
UINT32 *OutRemainder)
{
ACPI_FUNCTION_TRACE (UtShortDivide);
/* Always check for a zero divisor */
if (Divisor == 0)
{
ACPI_ERROR ((AE_INFO, "Divide by zero"));
return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
}
/* Return only what was requested */
if (OutQuotient)
{
*OutQuotient = InDividend / Divisor;
}
if (OutRemainder)
{
*OutRemainder = (UINT32) (InDividend % Divisor);
}
return_ACPI_STATUS (AE_OK);
}
ACPI_STATUS
AcpiUtDivide (
UINT64 InDividend,
UINT64 InDivisor,
UINT64 *OutQuotient,
UINT64 *OutRemainder)
{
ACPI_FUNCTION_TRACE (UtDivide);
/* Always check for a zero divisor */
if (InDivisor == 0)
{
ACPI_ERROR ((AE_INFO, "Divide by zero"));
return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
}
/* Return only what was requested */
if (OutQuotient)
{
*OutQuotient = InDividend / InDivisor;
}
if (OutRemainder)
{
*OutRemainder = InDividend % InDivisor;
}
return_ACPI_STATUS (AE_OK);
}
#endif