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494 lines
13 KiB
494 lines
13 KiB
// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
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/******************************************************************************* |
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* |
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* Module Name: utmath - Integer math support routines |
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* |
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******************************************************************************/ |
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#include <acpi/acpi.h> |
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#include "accommon.h" |
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#define _COMPONENT ACPI_UTILITIES |
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ACPI_MODULE_NAME("utmath") |
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/* Structures used only for 64-bit divide */ |
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typedef struct uint64_struct { |
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u32 lo; |
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u32 hi; |
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} uint64_struct; |
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typedef union uint64_overlay { |
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u64 full; |
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struct uint64_struct part; |
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} uint64_overlay; |
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/* |
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* Optional support for 64-bit double-precision integer multiply and shift. |
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* This code is configurable and is implemented in order to support 32-bit |
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* kernel environments where a 64-bit double-precision math library is not |
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* available. |
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*/ |
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#ifndef ACPI_USE_NATIVE_MATH64 |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_short_multiply |
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* |
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* PARAMETERS: multiplicand - 64-bit multiplicand |
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* multiplier - 32-bit multiplier |
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* out_product - Pointer to where the product is returned |
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* |
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* DESCRIPTION: Perform a short multiply. |
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* |
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******************************************************************************/ |
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acpi_status |
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acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product) |
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{ |
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union uint64_overlay multiplicand_ovl; |
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union uint64_overlay product; |
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u32 carry32; |
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ACPI_FUNCTION_TRACE(ut_short_multiply); |
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multiplicand_ovl.full = multiplicand; |
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/* |
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* The Product is 64 bits, the carry is always 32 bits, |
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* and is generated by the second multiply. |
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*/ |
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ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.hi, multiplier, |
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product.part.hi, carry32); |
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ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.lo, multiplier, |
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product.part.lo, carry32); |
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product.part.hi += carry32; |
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/* Return only what was requested */ |
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if (out_product) { |
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*out_product = product.full; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_short_shift_left |
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* |
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* PARAMETERS: operand - 64-bit shift operand |
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* count - 32-bit shift count |
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* out_result - Pointer to where the result is returned |
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* |
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* DESCRIPTION: Perform a short left shift. |
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* |
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******************************************************************************/ |
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acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result) |
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{ |
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union uint64_overlay operand_ovl; |
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ACPI_FUNCTION_TRACE(ut_short_shift_left); |
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operand_ovl.full = operand; |
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if ((count & 63) >= 32) { |
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operand_ovl.part.hi = operand_ovl.part.lo; |
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operand_ovl.part.lo = 0; |
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count = (count & 63) - 32; |
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} |
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ACPI_SHIFT_LEFT_64_BY_32(operand_ovl.part.hi, |
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operand_ovl.part.lo, count); |
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/* Return only what was requested */ |
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if (out_result) { |
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*out_result = operand_ovl.full; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_short_shift_right |
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* |
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* PARAMETERS: operand - 64-bit shift operand |
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* count - 32-bit shift count |
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* out_result - Pointer to where the result is returned |
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* |
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* DESCRIPTION: Perform a short right shift. |
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* |
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******************************************************************************/ |
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acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result) |
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{ |
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union uint64_overlay operand_ovl; |
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ACPI_FUNCTION_TRACE(ut_short_shift_right); |
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operand_ovl.full = operand; |
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if ((count & 63) >= 32) { |
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operand_ovl.part.lo = operand_ovl.part.hi; |
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operand_ovl.part.hi = 0; |
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count = (count & 63) - 32; |
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} |
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ACPI_SHIFT_RIGHT_64_BY_32(operand_ovl.part.hi, |
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operand_ovl.part.lo, count); |
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/* Return only what was requested */ |
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if (out_result) { |
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*out_result = operand_ovl.full; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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#else |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_short_multiply |
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* |
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* PARAMETERS: See function headers above |
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* |
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* DESCRIPTION: Native version of the ut_short_multiply function. |
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* |
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******************************************************************************/ |
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acpi_status |
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acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product) |
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{ |
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ACPI_FUNCTION_TRACE(ut_short_multiply); |
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/* Return only what was requested */ |
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if (out_product) { |
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*out_product = multiplicand * multiplier; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_short_shift_left |
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* |
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* PARAMETERS: See function headers above |
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* |
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* DESCRIPTION: Native version of the ut_short_shift_left function. |
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* |
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******************************************************************************/ |
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acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result) |
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{ |
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ACPI_FUNCTION_TRACE(ut_short_shift_left); |
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/* Return only what was requested */ |
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if (out_result) { |
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*out_result = operand << count; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_short_shift_right |
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* |
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* PARAMETERS: See function headers above |
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* |
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* DESCRIPTION: Native version of the ut_short_shift_right function. |
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* |
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******************************************************************************/ |
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acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result) |
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{ |
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ACPI_FUNCTION_TRACE(ut_short_shift_right); |
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/* Return only what was requested */ |
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if (out_result) { |
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*out_result = operand >> count; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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#endif |
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/* |
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* Optional support for 64-bit double-precision integer divide. This code |
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* is configurable and is implemented in order to support 32-bit kernel |
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* environments where a 64-bit double-precision math library is not available. |
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* |
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* Support for a more normal 64-bit divide/modulo (with check for a divide- |
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* by-zero) appears after this optional section of code. |
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*/ |
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#ifndef ACPI_USE_NATIVE_DIVIDE |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_short_divide |
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* |
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* PARAMETERS: dividend - 64-bit dividend |
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* divisor - 32-bit divisor |
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* out_quotient - Pointer to where the quotient is returned |
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* out_remainder - Pointer to where the remainder is returned |
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* |
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* RETURN: Status (Checks for divide-by-zero) |
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* |
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* DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits) |
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* divide and modulo. The result is a 64-bit quotient and a |
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* 32-bit remainder. |
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* |
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******************************************************************************/ |
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acpi_status |
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acpi_ut_short_divide(u64 dividend, |
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u32 divisor, u64 *out_quotient, u32 *out_remainder) |
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{ |
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union uint64_overlay dividend_ovl; |
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union uint64_overlay quotient; |
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u32 remainder32; |
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ACPI_FUNCTION_TRACE(ut_short_divide); |
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/* Always check for a zero divisor */ |
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if (divisor == 0) { |
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ACPI_ERROR((AE_INFO, "Divide by zero")); |
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return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO); |
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} |
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dividend_ovl.full = dividend; |
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/* |
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* The quotient is 64 bits, the remainder is always 32 bits, |
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* and is generated by the second divide. |
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*/ |
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ACPI_DIV_64_BY_32(0, dividend_ovl.part.hi, divisor, |
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quotient.part.hi, remainder32); |
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ACPI_DIV_64_BY_32(remainder32, dividend_ovl.part.lo, divisor, |
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quotient.part.lo, remainder32); |
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/* Return only what was requested */ |
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if (out_quotient) { |
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*out_quotient = quotient.full; |
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} |
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if (out_remainder) { |
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*out_remainder = remainder32; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_divide |
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* |
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* PARAMETERS: in_dividend - Dividend |
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* in_divisor - Divisor |
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* out_quotient - Pointer to where the quotient is returned |
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* out_remainder - Pointer to where the remainder is returned |
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* |
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* RETURN: Status (Checks for divide-by-zero) |
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* |
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* DESCRIPTION: Perform a divide and modulo. |
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* |
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******************************************************************************/ |
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acpi_status |
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acpi_ut_divide(u64 in_dividend, |
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u64 in_divisor, u64 *out_quotient, u64 *out_remainder) |
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{ |
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union uint64_overlay dividend; |
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union uint64_overlay divisor; |
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union uint64_overlay quotient; |
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union uint64_overlay remainder; |
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union uint64_overlay normalized_dividend; |
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union uint64_overlay normalized_divisor; |
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u32 partial1; |
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union uint64_overlay partial2; |
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union uint64_overlay partial3; |
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ACPI_FUNCTION_TRACE(ut_divide); |
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/* Always check for a zero divisor */ |
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if (in_divisor == 0) { |
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ACPI_ERROR((AE_INFO, "Divide by zero")); |
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return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO); |
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} |
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divisor.full = in_divisor; |
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dividend.full = in_dividend; |
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if (divisor.part.hi == 0) { |
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/* |
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* 1) Simplest case is where the divisor is 32 bits, we can |
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* just do two divides |
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*/ |
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remainder.part.hi = 0; |
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/* |
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* The quotient is 64 bits, the remainder is always 32 bits, |
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* and is generated by the second divide. |
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*/ |
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ACPI_DIV_64_BY_32(0, dividend.part.hi, divisor.part.lo, |
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quotient.part.hi, partial1); |
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ACPI_DIV_64_BY_32(partial1, dividend.part.lo, divisor.part.lo, |
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quotient.part.lo, remainder.part.lo); |
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} |
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else { |
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/* |
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* 2) The general case where the divisor is a full 64 bits |
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* is more difficult |
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*/ |
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quotient.part.hi = 0; |
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normalized_dividend = dividend; |
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normalized_divisor = divisor; |
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/* Normalize the operands (shift until the divisor is < 32 bits) */ |
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do { |
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ACPI_SHIFT_RIGHT_64(normalized_divisor.part.hi, |
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normalized_divisor.part.lo); |
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ACPI_SHIFT_RIGHT_64(normalized_dividend.part.hi, |
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normalized_dividend.part.lo); |
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} while (normalized_divisor.part.hi != 0); |
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/* Partial divide */ |
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ACPI_DIV_64_BY_32(normalized_dividend.part.hi, |
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normalized_dividend.part.lo, |
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normalized_divisor.part.lo, quotient.part.lo, |
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partial1); |
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/* |
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* The quotient is always 32 bits, and simply requires |
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* adjustment. The 64-bit remainder must be generated. |
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*/ |
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partial1 = quotient.part.lo * divisor.part.hi; |
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partial2.full = (u64) quotient.part.lo * divisor.part.lo; |
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partial3.full = (u64) partial2.part.hi + partial1; |
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remainder.part.hi = partial3.part.lo; |
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remainder.part.lo = partial2.part.lo; |
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if (partial3.part.hi == 0) { |
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if (partial3.part.lo >= dividend.part.hi) { |
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if (partial3.part.lo == dividend.part.hi) { |
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if (partial2.part.lo > dividend.part.lo) { |
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quotient.part.lo--; |
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remainder.full -= divisor.full; |
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} |
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} else { |
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quotient.part.lo--; |
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remainder.full -= divisor.full; |
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} |
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} |
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remainder.full = remainder.full - dividend.full; |
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remainder.part.hi = (u32)-((s32)remainder.part.hi); |
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remainder.part.lo = (u32)-((s32)remainder.part.lo); |
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if (remainder.part.lo) { |
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remainder.part.hi--; |
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} |
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} |
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} |
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/* Return only what was requested */ |
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if (out_quotient) { |
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*out_quotient = quotient.full; |
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} |
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if (out_remainder) { |
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*out_remainder = remainder.full; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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#else |
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/******************************************************************************* |
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* |
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* FUNCTION: acpi_ut_short_divide, acpi_ut_divide |
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* |
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* PARAMETERS: See function headers above |
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* |
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* DESCRIPTION: Native versions of the ut_divide functions. Use these if either |
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* 1) The target is a 64-bit platform and therefore 64-bit |
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* integer math is supported directly by the machine. |
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* 2) The target is a 32-bit or 16-bit platform, and the |
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* double-precision integer math library is available to |
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* perform the divide. |
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* |
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******************************************************************************/ |
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acpi_status |
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acpi_ut_short_divide(u64 in_dividend, |
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u32 divisor, u64 *out_quotient, u32 *out_remainder) |
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{ |
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ACPI_FUNCTION_TRACE(ut_short_divide); |
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/* Always check for a zero divisor */ |
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if (divisor == 0) { |
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ACPI_ERROR((AE_INFO, "Divide by zero")); |
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return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO); |
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} |
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/* Return only what was requested */ |
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if (out_quotient) { |
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*out_quotient = in_dividend / divisor; |
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} |
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if (out_remainder) { |
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*out_remainder = (u32) (in_dividend % divisor); |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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acpi_status |
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acpi_ut_divide(u64 in_dividend, |
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u64 in_divisor, u64 *out_quotient, u64 *out_remainder) |
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{ |
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ACPI_FUNCTION_TRACE(ut_divide); |
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/* Always check for a zero divisor */ |
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if (in_divisor == 0) { |
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ACPI_ERROR((AE_INFO, "Divide by zero")); |
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return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO); |
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} |
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/* Return only what was requested */ |
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if (out_quotient) { |
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*out_quotient = in_dividend / in_divisor; |
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} |
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if (out_remainder) { |
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*out_remainder = in_dividend % in_divisor; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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#endif
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