[deliverable/linux.git] / drivers / acpi / utilities / utmath.c

/*******************************************************************************
 *
 * Module Name: utmath - Integer math support routines
 *
 ******************************************************************************/

/*
 * Copyright (C) 2000 - 2008, 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 <acpi/accommon.h>

#define _COMPONENT          ACPI_UTILITIES
ACPI_MODULE_NAME("utmath")

/*
 * Support for double-precision integer divide.  This code is included here
 * in order to support kernel environments where the double-precision math
 * library is not available.
 */
#ifndef ACPI_USE_NATIVE_DIVIDE
/*******************************************************************************
 *
 * 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(acpi_integer dividend,
		     u32 divisor,
		     acpi_integer * 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(acpi_integer in_dividend,
	       acpi_integer in_divisor,
	       acpi_integer * out_quotient, acpi_integer * 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 =
		    (acpi_integer) quotient.part.lo * divisor.part.lo;
		partial3.full = (acpi_integer) 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(acpi_integer in_dividend,
		     u32 divisor,
		     acpi_integer * 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(acpi_integer in_dividend,
	       acpi_integer in_divisor,
	       acpi_integer * out_quotient, acpi_integer * 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
Commit	Line	Data
1da177e4 LT	1	/*******************************************************************************
	2	*
	3	* Module Name: utmath - Integer math support routines
	4	*
	5	******************************************************************************/
	6
	7	/*
75a44ce0	8	* Copyright (C) 2000 - 2008, Intel Corp.
1da177e4 LT	9	* All rights reserved.
	10	*
	11	* Redistribution and use in source and binary forms, with or without
	12	* modification, are permitted provided that the following conditions
	13	* are met:
	14	* 1. Redistributions of source code must retain the above copyright
	15	* notice, this list of conditions, and the following disclaimer,
	16	* without modification.
	17	* 2. Redistributions in binary form must reproduce at minimum a disclaimer
	18	* substantially similar to the "NO WARRANTY" disclaimer below
	19	* ("Disclaimer") and any redistribution must be conditioned upon
	20	* including a substantially similar Disclaimer requirement for further
	21	* binary redistribution.
	22	* 3. Neither the names of the above-listed copyright holders nor the names
	23	* of any contributors may be used to endorse or promote products derived
	24	* from this software without specific prior written permission.
	25	*
	26	* Alternatively, this software may be distributed under the terms of the
	27	* GNU General Public License ("GPL") version 2 as published by the Free
	28	* Software Foundation.
	29	*
	30	* NO WARRANTY
	31	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	32	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	33	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
	34	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	35	* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	36	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	37	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	38	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	39	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
	40	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	41	* POSSIBILITY OF SUCH DAMAGES.
	42	*/
	43
1da177e4	44	#include <acpi/acpi.h>
50df4d8b	45	#include <acpi/accommon.h>
1da177e4	46
1da177e4	47	#define _COMPONENT ACPI_UTILITIES
4be44fcd	48	ACPI_MODULE_NAME("utmath")
1da177e4 LT	49
	50	/*
	51	* Support for double-precision integer divide. This code is included here
	52	* in order to support kernel environments where the double-precision math
	53	* library is not available.
	54	*/
1da177e4 LT	55	#ifndef ACPI_USE_NATIVE_DIVIDE
	56	/*******************************************************************************
	57	*
	58	* FUNCTION: acpi_ut_short_divide
	59	*
	60	* PARAMETERS: Dividend - 64-bit dividend
	61	* Divisor - 32-bit divisor
	62	* out_quotient - Pointer to where the quotient is returned
	63	* out_remainder - Pointer to where the remainder is returned
	64	*
	65	* RETURN: Status (Checks for divide-by-zero)
	66	*
	67	* DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)
	68	* divide and modulo. The result is a 64-bit quotient and a
	69	* 32-bit remainder.
	70	*
	71	******************************************************************************/
1da177e4	72	acpi_status
4be44fcd LB	73	acpi_ut_short_divide(acpi_integer dividend,
	74	u32 divisor,
	75	acpi_integer * out_quotient, u32 * out_remainder)
1da177e4	76	{
4be44fcd LB	77	union uint64_overlay dividend_ovl;
	78	union uint64_overlay quotient;
	79	u32 remainder32;
1da177e4	80
b229cf92	81	ACPI_FUNCTION_TRACE(ut_short_divide);
1da177e4 LT	82
	83	/* Always check for a zero divisor */
	84
	85	if (divisor == 0) {
b8e4d893	86	ACPI_ERROR((AE_INFO, "Divide by zero"));
4be44fcd	87	return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
1da177e4 LT	88	}
	89
	90	dividend_ovl.full = dividend;
	91
	92	/*
	93	* The quotient is 64 bits, the remainder is always 32 bits,
	94	* and is generated by the second divide.
	95	*/
4be44fcd	96	ACPI_DIV_64_BY_32(0, dividend_ovl.part.hi, divisor,
1da177e4	97	quotient.part.hi, remainder32);
4be44fcd	98	ACPI_DIV_64_BY_32(remainder32, dividend_ovl.part.lo, divisor,
1da177e4 LT	99	quotient.part.lo, remainder32);
	100
	101	/* Return only what was requested */
	102
	103	if (out_quotient) {
	104	*out_quotient = quotient.full;
	105	}
	106	if (out_remainder) {
	107	*out_remainder = remainder32;
	108	}
	109
4be44fcd	110	return_ACPI_STATUS(AE_OK);
1da177e4 LT	111	}
1da177e4 LT	112
1da177e4 LT	113	/*******************************************************************************
	114	*
	115	* FUNCTION: acpi_ut_divide
	116	*
	117	* PARAMETERS: in_dividend - Dividend
	118	* in_divisor - Divisor
	119	* out_quotient - Pointer to where the quotient is returned
	120	* out_remainder - Pointer to where the remainder is returned
	121	*
	122	* RETURN: Status (Checks for divide-by-zero)
	123	*
	124	* DESCRIPTION: Perform a divide and modulo.
	125	*
	126	******************************************************************************/
	127
	128	acpi_status
4be44fcd LB	129	acpi_ut_divide(acpi_integer in_dividend,
	130	acpi_integer in_divisor,
	131	acpi_integer * out_quotient, acpi_integer * out_remainder)
1da177e4	132	{
4be44fcd LB	133	union uint64_overlay dividend;
	134	union uint64_overlay divisor;
	135	union uint64_overlay quotient;
	136	union uint64_overlay remainder;
	137	union uint64_overlay normalized_dividend;
	138	union uint64_overlay normalized_divisor;
	139	u32 partial1;
	140	union uint64_overlay partial2;
	141	union uint64_overlay partial3;
	142
b229cf92	143	ACPI_FUNCTION_TRACE(ut_divide);
1da177e4 LT	144
	145	/* Always check for a zero divisor */
	146
	147	if (in_divisor == 0) {
b8e4d893	148	ACPI_ERROR((AE_INFO, "Divide by zero"));
4be44fcd	149	return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
1da177e4 LT	150	}
1da177e4 LT	151
4be44fcd	152	divisor.full = in_divisor;
1da177e4 LT	153	dividend.full = in_dividend;
	154	if (divisor.part.hi == 0) {
	155	/*
	156	* 1) Simplest case is where the divisor is 32 bits, we can
	157	* just do two divides
	158	*/
	159	remainder.part.hi = 0;
	160
	161	/*
	162	* The quotient is 64 bits, the remainder is always 32 bits,
	163	* and is generated by the second divide.
	164	*/
4be44fcd	165	ACPI_DIV_64_BY_32(0, dividend.part.hi, divisor.part.lo,
1da177e4	166	quotient.part.hi, partial1);
4be44fcd	167	ACPI_DIV_64_BY_32(partial1, dividend.part.lo, divisor.part.lo,
1da177e4 LT	168	quotient.part.lo, remainder.part.lo);
	169	}
	170
	171	else {
	172	/*
	173	* 2) The general case where the divisor is a full 64 bits
	174	* is more difficult
	175	*/
4be44fcd	176	quotient.part.hi = 0;
1da177e4 LT	177	normalized_dividend = dividend;
	178	normalized_divisor = divisor;
	179
	180	/* Normalize the operands (shift until the divisor is < 32 bits) */
	181
	182	do {
4be44fcd LB	183	ACPI_SHIFT_RIGHT_64(normalized_divisor.part.hi,
	184	normalized_divisor.part.lo);
	185	ACPI_SHIFT_RIGHT_64(normalized_dividend.part.hi,
	186	normalized_dividend.part.lo);
1da177e4 LT	187
	188	} while (normalized_divisor.part.hi != 0);
	189
	190	/* Partial divide */
	191
4be44fcd	192	ACPI_DIV_64_BY_32(normalized_dividend.part.hi,
1da177e4 LT	193	normalized_dividend.part.lo,
	194	normalized_divisor.part.lo,
	195	quotient.part.lo, partial1);
	196
	197	/*
	198	* The quotient is always 32 bits, and simply requires adjustment.
	199	* The 64-bit remainder must be generated.
	200	*/
4be44fcd LB	201	partial1 = quotient.part.lo * divisor.part.hi;
	202	partial2.full =
	203	(acpi_integer) quotient.part.lo * divisor.part.lo;
1da177e4 LT	204	partial3.full = (acpi_integer) partial2.part.hi + partial1;
	205
	206	remainder.part.hi = partial3.part.lo;
	207	remainder.part.lo = partial2.part.lo;
	208
	209	if (partial3.part.hi == 0) {
	210	if (partial3.part.lo >= dividend.part.hi) {
	211	if (partial3.part.lo == dividend.part.hi) {
	212	if (partial2.part.lo > dividend.part.lo) {
	213	quotient.part.lo--;
	214	remainder.full -= divisor.full;
	215	}
4be44fcd	216	} else {
1da177e4 LT	217	quotient.part.lo--;
	218	remainder.full -= divisor.full;
	219	}
	220	}
	221
4be44fcd LB	222	remainder.full = remainder.full - dividend.full;
	223	remainder.part.hi = (u32) - ((s32) remainder.part.hi);
	224	remainder.part.lo = (u32) - ((s32) remainder.part.lo);
1da177e4 LT	225
	226	if (remainder.part.lo) {
	227	remainder.part.hi--;
	228	}
	229	}
	230	}
	231
	232	/* Return only what was requested */
	233
	234	if (out_quotient) {
	235	*out_quotient = quotient.full;
	236	}
	237	if (out_remainder) {
	238	*out_remainder = remainder.full;
	239	}
	240
4be44fcd	241	return_ACPI_STATUS(AE_OK);
1da177e4 LT	242	}
	243
	244	#else
1da177e4 LT	245	/*******************************************************************************
	246	*
	247	* FUNCTION: acpi_ut_short_divide, acpi_ut_divide
	248	*
44f6c012 RM	249	* PARAMETERS: See function headers above
44f6c012 RM	250	*
1da177e4 LT	251	* DESCRIPTION: Native versions of the ut_divide functions. Use these if either
	252	* 1) The target is a 64-bit platform and therefore 64-bit
	253	* integer math is supported directly by the machine.
	254	* 2) The target is a 32-bit or 16-bit platform, and the
	255	* double-precision integer math library is available to
	256	* perform the divide.
	257	*
	258	******************************************************************************/
1da177e4	259	acpi_status
4be44fcd LB	260	acpi_ut_short_divide(acpi_integer in_dividend,
	261	u32 divisor,
	262	acpi_integer * out_quotient, u32 * out_remainder)
1da177e4 LT	263	{
1da177e4 LT	264
b229cf92	265	ACPI_FUNCTION_TRACE(ut_short_divide);
1da177e4 LT	266
	267	/* Always check for a zero divisor */
	268
	269	if (divisor == 0) {
b8e4d893	270	ACPI_ERROR((AE_INFO, "Divide by zero"));
4be44fcd	271	return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
1da177e4 LT	272	}
	273
	274	/* Return only what was requested */
	275
	276	if (out_quotient) {
	277	*out_quotient = in_dividend / divisor;
	278	}
	279	if (out_remainder) {
1f549a24	280	*out_remainder = (u32) (in_dividend % divisor);
1da177e4 LT	281	}
1da177e4 LT	282
4be44fcd	283	return_ACPI_STATUS(AE_OK);
1da177e4 LT	284	}
	285
	286	acpi_status
4be44fcd LB	287	acpi_ut_divide(acpi_integer in_dividend,
	288	acpi_integer in_divisor,
	289	acpi_integer * out_quotient, acpi_integer * out_remainder)
1da177e4	290	{
b229cf92	291	ACPI_FUNCTION_TRACE(ut_divide);
1da177e4 LT	292
	293	/* Always check for a zero divisor */
	294
	295	if (in_divisor == 0) {
b8e4d893	296	ACPI_ERROR((AE_INFO, "Divide by zero"));
4be44fcd	297	return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
1da177e4 LT	298	}
1da177e4 LT	299
1da177e4 LT	300	/* Return only what was requested */
	301
	302	if (out_quotient) {
	303	*out_quotient = in_dividend / in_divisor;
	304	}
	305	if (out_remainder) {
	306	*out_remainder = in_dividend % in_divisor;
	307	}
	308
4be44fcd	309	return_ACPI_STATUS(AE_OK);
1da177e4 LT	310	}
	311
	312	#endif