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/******************************************************************************* * * 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