| /******************************************************************************* |
| * |
| * Module Name: utmath - Integer math support routines |
| * |
| ******************************************************************************/ |
| |
| /* |
| * Copyright (C) 2000 - 2016, 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. |
| */ |
| |
| #include "acpi.h" |
| #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 |
