WebSVN – HelenOS-historic – Blame – /uspace/trunk/softfloat/generic/add.c

Rev	Author	Line No.	Line
731	cejka	1	/*
		2	* Copyright (C) 2005 Josef Cejka
		3	* All rights reserved.
		4	*
		5	* Redistribution and use in source and binary forms, with or without
		6	* modification, are permitted provided that the following conditions
		7	* are met:
		8	*
		9	* - Redistributions of source code must retain the above copyright
		10	* notice, this list of conditions and the following disclaimer.
		11	* - Redistributions in binary form must reproduce the above copyright
		12	* notice, this list of conditions and the following disclaimer in the
		13	* documentation and/or other materials provided with the distribution.
		14	* - The name of the author may not be used to endorse or promote products
		15	* derived from this software without specific prior written permission.
		16	*
		17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		27	*/
		28
		29	#include<sftypes.h>
		30	#include<add.h>
		31	#include<comparison.h>
		32
		33	/** Add two Float32 numbers with same signs
		34	*/
		35	float32 addFloat32(float32 a, float32 b)
		36	{
		37	int expdiff;
		38	__u32 exp1, exp2,mant1, mant2;
		39
732	cejka	40	expdiff = a.parts.exp - b.parts.exp;
		41	if (expdiff < 0) {
731	cejka	42	if (isFloat32NaN(b)) {
		43	//TODO: fix SigNaN
		44	if (isFloat32SigNaN(b)) {
		45	};
		46
		47	return b;
		48	};
		49
732	cejka	50	if (b.parts.exp == FLOAT32_MAX_EXPONENT) {
731	cejka	51	return b;
		52	}
		53
732	cejka	54	mant1 = b.parts.mantisa;
		55	exp1 = b.parts.exp;
		56	mant2 = a.parts.mantisa;
		57	exp2 = a.parts.exp;
		58	expdiff *= -1;
731	cejka	59	} else {
		60	if (isFloat32NaN(a)) {
		61	//TODO: fix SigNaN
732	cejka	62	if (isFloat32SigNaN(a) \|\| isFloat32SigNaN(b)) {
731	cejka	63	};
		64	return a;
		65	};
		66
732	cejka	67	if (a.parts.exp == FLOAT32_MAX_EXPONENT) {
731	cejka	68	return a;
		69	}
		70
732	cejka	71	mant1 = a.parts.mantisa;
		72	exp1 = a.parts.exp;
		73	mant2 = b.parts.mantisa;
		74	exp2 = b.parts.exp;
731	cejka	75	};
		76
		77	if (exp1 == 0) {
		78	/* both are denormalized */
		79	mant1 += mant2;
		80	if (mant1 & FLOAT32_HIDDEN_BIT_MASK ) {
		81	/* result is not denormalized */
		82	a.parts.exp = 1;
		83	};
		84	a.parts.mantisa = mant1;
		85	return a;
		86	};
		87
		88	mant1 \|= FLOAT32_HIDDEN_BIT_MASK; //add hidden bit
		89
		90	if (exp2 == 0) {
		91	/* second operand is denormalized */
		92	--expdiff;
		93	} else {
		94	/* add hidden bit to second operand */
		95	mant2 \|= FLOAT32_HIDDEN_BIT_MASK;
		96	};
		97
		98	/* create some space for rounding */
		99	mant1 <<= 6;
		100	mant2 <<= 6;
		101
732	cejka	102	if (expdiff > (FLOAT32_MANTISA_SIZE + 1) ) {
731	cejka	103	goto done;
		104	};
		105
732	cejka	106	mant2 >>= expdiff;
		107	mant1 += mant2;
731	cejka	108	done:
732	cejka	109	if (mant1 & (FLOAT32_HIDDEN_BIT_MASK << 7) ) {
731	cejka	110	++exp1;
		111	mant1 >>= 1;
		112	};
		113
		114	/* rounding - if first bit after mantisa is set then round up */
		115	mant1 += (0x1 << 5);
		116
732	cejka	117	if (mant1 & (FLOAT32_HIDDEN_BIT_MASK << 7)) {
731	cejka	118	++exp1;
732	cejka	119	mant1 >>= 1;
731	cejka	120	};
		121
		122	a.parts.exp = exp1;
		123
		124	/Clear hidden bit and shift /
732	cejka	125	a.parts.mantisa = ((mant1 >> 6) & (~FLOAT32_HIDDEN_BIT_MASK)) ;
731	cejka	126	return a;
		127	}
		128
		129
		130	/** Add two Float64 numbers with same signs
		131	*/
		132	float64 addFloat64(float64 a, float64 b)
		133	{
		134	int expdiff;
732	cejka	135	__u64 exp1, exp2, mant1, mant2;
731	cejka	136
732	cejka	137	expdiff = a.parts.exp - b.parts.exp;
		138	if (expdiff < 0) {
731	cejka	139	if (isFloat64NaN(b)) {
		140	//TODO: fix SigNaN
		141	if (isFloat64SigNaN(b)) {
		142	};
		143
		144	return b;
		145	};
		146
		147	/* b is infinity and a not */
732	cejka	148	if (b.parts.exp == FLOAT64_MAX_EXPONENT ) {
731	cejka	149	return b;
		150	}
		151
732	cejka	152	mant1 = b.parts.mantisa;
		153	exp1 = b.parts.exp;
		154	mant2 = a.parts.mantisa;
		155	exp2 = a.parts.exp;
		156	expdiff *= -1;
731	cejka	157	} else {
		158	if (isFloat64NaN(a)) {
		159	//TODO: fix SigNaN
732	cejka	160	if (isFloat64SigNaN(a) \|\| isFloat64SigNaN(b)) {
731	cejka	161	};
		162	return a;
		163	};
		164
		165	/* a is infinity and b not */
732	cejka	166	if (a.parts.exp == FLOAT64_MAX_EXPONENT ) {
731	cejka	167	return a;
		168	}
		169
		170	mant1 = a.parts.mantisa;
		171	exp1 = a.parts.exp;
		172	mant2 = b.parts.mantisa;
		173	exp2 = b.parts.exp;
		174	};
		175
		176	if (exp1 == 0) {
		177	/* both are denormalized */
		178	mant1 += mant2;
		179	if (mant1 & FLOAT64_HIDDEN_BIT_MASK) {
		180	/* result is not denormalized */
		181	a.parts.exp = 1;
		182	};
		183	a.parts.mantisa = mant1;
		184	return a;
		185	};
		186
		187	/* add hidden bit - mant1 is sure not denormalized */
		188	mant1 \|= FLOAT64_HIDDEN_BIT_MASK;
		189
		190	/* second operand ... */
		191	if (exp2 == 0) {
		192	/* ... is denormalized */
		193	--expdiff;
		194	} else {
		195	/* is not denormalized */
		196	mant2 \|= FLOAT64_HIDDEN_BIT_MASK;
		197	};
		198
		199	/* create some space for rounding */
		200	mant1 <<= 6;
		201	mant2 <<= 6;
		202
732	cejka	203	if (expdiff > (FLOAT64_MANTISA_SIZE + 1) ) {
731	cejka	204	goto done;
		205	};
		206
		207	mant2 >>= expdiff;
		208	mant1 += mant2;
		209	done:
732	cejka	210	if (mant1 & (FLOAT64_HIDDEN_BIT_MASK << 7) ) {
731	cejka	211	++exp1;
		212	mant1 >>= 1;
		213	};
		214
		215	/* rounding - if first bit after mantisa is set then round up */
		216	mant1 += (0x1 << 5);
		217
732	cejka	218	if (mant1 & (FLOAT64_HIDDEN_BIT_MASK << 7)) {
731	cejka	219	++exp1;
732	cejka	220	mant1 >>= 1;
731	cejka	221	};
		222
		223	a.parts.exp = exp1;
		224	/Clear hidden bit and shift /
732	cejka	225	a.parts.mantisa = ( (mant1 >> 6 ) & (~FLOAT64_HIDDEN_BIT_MASK));
731	cejka	226	return a;
		227	}
		228
		229

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(root)/uspace/trunk/softfloat/generic/add.c @ 1740 – Rev 732