--- /dev/null
+/*******************************************************************************
+ *
+ * Module Name: utmath - Integer math support routines
+ *
+ ******************************************************************************/
+
+/*
+ * Copyright (C) 2000 - 2015, 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
Code Review / kvmfornfv.git / blobdiff