327 lines
9.4 KiB
C
327 lines
9.4 KiB
C
/*******************************************************************************
|
|
*
|
|
* 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/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 {
|
|
u32 lo;
|
|
u32 hi;
|
|
|
|
} uint64_struct;
|
|
|
|
typedef union uint64_overlay {
|
|
u64 full;
|
|
struct uint64_struct part;
|
|
|
|
} uint64_overlay;
|
|
|
|
/*******************************************************************************
|
|
*
|
|
* FUNCTION: acpi_ut_short_divide
|
|
*
|
|
* PARAMETERS: dividend - 64-bit dividend
|
|
* divisor - 32-bit divisor
|
|
* out_quotient - Pointer to where the quotient is returned
|
|
* out_remainder - 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
|
|
acpi_ut_short_divide(u64 dividend,
|
|
u32 divisor, u64 *out_quotient, u32 *out_remainder)
|
|
{
|
|
union uint64_overlay dividend_ovl;
|
|
union uint64_overlay quotient;
|
|
u32 remainder32;
|
|
|
|
ACPI_FUNCTION_TRACE(ut_short_divide);
|
|
|
|
/* Always check for a zero divisor */
|
|
|
|
if (divisor == 0) {
|
|
ACPI_ERROR((AE_INFO, "Divide by zero"));
|
|
return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
|
|
}
|
|
|
|
dividend_ovl.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, dividend_ovl.part.hi, divisor,
|
|
quotient.part.hi, remainder32);
|
|
|
|
ACPI_DIV_64_BY_32(remainder32, dividend_ovl.part.lo, divisor,
|
|
quotient.part.lo, remainder32);
|
|
|
|
/* Return only what was requested */
|
|
|
|
if (out_quotient) {
|
|
*out_quotient = quotient.full;
|
|
}
|
|
if (out_remainder) {
|
|
*out_remainder = remainder32;
|
|
}
|
|
|
|
return_ACPI_STATUS(AE_OK);
|
|
}
|
|
|
|
/*******************************************************************************
|
|
*
|
|
* FUNCTION: acpi_ut_divide
|
|
*
|
|
* PARAMETERS: in_dividend - Dividend
|
|
* in_divisor - Divisor
|
|
* out_quotient - Pointer to where the quotient is returned
|
|
* out_remainder - Pointer to where the remainder is returned
|
|
*
|
|
* RETURN: Status (Checks for divide-by-zero)
|
|
*
|
|
* DESCRIPTION: Perform a divide and modulo.
|
|
*
|
|
******************************************************************************/
|
|
|
|
acpi_status
|
|
acpi_ut_divide(u64 in_dividend,
|
|
u64 in_divisor, u64 *out_quotient, u64 *out_remainder)
|
|
{
|
|
union uint64_overlay dividend;
|
|
union uint64_overlay divisor;
|
|
union uint64_overlay quotient;
|
|
union uint64_overlay remainder;
|
|
union uint64_overlay normalized_dividend;
|
|
union uint64_overlay normalized_divisor;
|
|
u32 partial1;
|
|
union uint64_overlay partial2;
|
|
union uint64_overlay partial3;
|
|
|
|
ACPI_FUNCTION_TRACE(ut_divide);
|
|
|
|
/* Always check for a zero divisor */
|
|
|
|
if (in_divisor == 0) {
|
|
ACPI_ERROR((AE_INFO, "Divide by zero"));
|
|
return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
|
|
}
|
|
|
|
divisor.full = in_divisor;
|
|
dividend.full = in_dividend;
|
|
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;
|
|
normalized_dividend = dividend;
|
|
normalized_divisor = divisor;
|
|
|
|
/* Normalize the operands (shift until the divisor is < 32 bits) */
|
|
|
|
do {
|
|
ACPI_SHIFT_RIGHT_64(normalized_divisor.part.hi,
|
|
normalized_divisor.part.lo);
|
|
ACPI_SHIFT_RIGHT_64(normalized_dividend.part.hi,
|
|
normalized_dividend.part.lo);
|
|
|
|
} while (normalized_divisor.part.hi != 0);
|
|
|
|
/* Partial divide */
|
|
|
|
ACPI_DIV_64_BY_32(normalized_dividend.part.hi,
|
|
normalized_dividend.part.lo,
|
|
normalized_divisor.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 = (u64) quotient.part.lo * divisor.part.lo;
|
|
partial3.full = (u64) 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 = (u32)-((s32)remainder.part.hi);
|
|
remainder.part.lo = (u32)-((s32)remainder.part.lo);
|
|
|
|
if (remainder.part.lo) {
|
|
remainder.part.hi--;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Return only what was requested */
|
|
|
|
if (out_quotient) {
|
|
*out_quotient = quotient.full;
|
|
}
|
|
if (out_remainder) {
|
|
*out_remainder = remainder.full;
|
|
}
|
|
|
|
return_ACPI_STATUS(AE_OK);
|
|
}
|
|
|
|
#else
|
|
/*******************************************************************************
|
|
*
|
|
* FUNCTION: acpi_ut_short_divide, acpi_ut_divide
|
|
*
|
|
* PARAMETERS: See function headers above
|
|
*
|
|
* DESCRIPTION: Native versions of the ut_divide 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
|
|
acpi_ut_short_divide(u64 in_dividend,
|
|
u32 divisor, u64 *out_quotient, u32 *out_remainder)
|
|
{
|
|
|
|
ACPI_FUNCTION_TRACE(ut_short_divide);
|
|
|
|
/* 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 (out_quotient) {
|
|
*out_quotient = in_dividend / divisor;
|
|
}
|
|
if (out_remainder) {
|
|
*out_remainder = (u32) (in_dividend % divisor);
|
|
}
|
|
|
|
return_ACPI_STATUS(AE_OK);
|
|
}
|
|
|
|
acpi_status
|
|
acpi_ut_divide(u64 in_dividend,
|
|
u64 in_divisor, u64 *out_quotient, u64 *out_remainder)
|
|
{
|
|
ACPI_FUNCTION_TRACE(ut_divide);
|
|
|
|
/* Always check for a zero divisor */
|
|
|
|
if (in_divisor == 0) {
|
|
ACPI_ERROR((AE_INFO, "Divide by zero"));
|
|
return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
|
|
}
|
|
|
|
/* Return only what was requested */
|
|
|
|
if (out_quotient) {
|
|
*out_quotient = in_dividend / in_divisor;
|
|
}
|
|
if (out_remainder) {
|
|
*out_remainder = in_dividend % in_divisor;
|
|
}
|
|
|
|
return_ACPI_STATUS(AE_OK);
|
|
}
|
|
|
|
#endif
|