aboutsummaryrefslogtreecommitdiff
path: root/arch/parisc/math-emu/fcnvxf.c
blob: 05c7fadb372900fd9bf22814b59bca9da1931121 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
/*
 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
 *
 * Floating-point emulation code
 *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
/*
 * BEGIN_DESC
 *
 *  File:
 *	@(#)	pa/spmath/fcnvxf.c		$Revision: 1.1 $
 *
 *  Purpose:
 *	Single Fixed-point to Single Floating-point
 *	Single Fixed-point to Double Floating-point 
 *	Double Fixed-point to Single Floating-point 
 *	Double Fixed-point to Double Floating-point 
 *
 *  External Interfaces:
 *	dbl_to_dbl_fcnvxf(srcptr,nullptr,dstptr,status)
 *	dbl_to_sgl_fcnvxf(srcptr,nullptr,dstptr,status)
 *	sgl_to_dbl_fcnvxf(srcptr,nullptr,dstptr,status)
 *	sgl_to_sgl_fcnvxf(srcptr,nullptr,dstptr,status)
 *
 *  Internal Interfaces:
 *
 *  Theory:
 *	<<please update with a overview of the operation of this file>>
 *
 * END_DESC
*/


#include "float.h"
#include "sgl_float.h"
#include "dbl_float.h"
#include "cnv_float.h"

/*
 *  Convert single fixed-point to single floating-point format
 */

int
sgl_to_sgl_fcnvxf(
		    int *srcptr,
		    unsigned int *nullptr,
		    sgl_floating_point *dstptr,
		    unsigned int *status)
{
	register int src, dst_exponent;
	register unsigned int result = 0;

	src = *srcptr;
	/* 
	 * set sign bit of result and get magnitude of source 
	 */
	if (src < 0) {
		Sgl_setone_sign(result);  
		Int_negate(src);
	}
	else {
		Sgl_setzero_sign(result);
        	/* Check for zero */ 
        	if (src == 0) { 
                	Sgl_setzero(result); 
			*dstptr = result;
                	return(NOEXCEPTION); 
        	} 
	}
	/*
	 * Generate exponent and normalized mantissa
	 */
	dst_exponent = 16;    /* initialize for normalization */
	/*
	 * Check word for most significant bit set.  Returns
	 * a value in dst_exponent indicating the bit position,
	 * between -1 and 30.
	 */
	Find_ms_one_bit(src,dst_exponent);
	/*  left justify source, with msb at bit position 1  */
	if (dst_exponent >= 0) src <<= dst_exponent;
	else src = 1 << 30;
	Sgl_set_mantissa(result, src >> (SGL_EXP_LENGTH-1));
	Sgl_set_exponent(result, 30+SGL_BIAS - dst_exponent);

	/* check for inexact */
	if (Int_isinexact_to_sgl(src)) {
		switch (Rounding_mode()) {
			case ROUNDPLUS: 
				if (Sgl_iszero_sign(result)) 
					Sgl_increment(result);
				break;
			case ROUNDMINUS: 
				if (Sgl_isone_sign(result)) 
					Sgl_increment(result);
				break;
			case ROUNDNEAREST:
				Sgl_roundnearest_from_int(src,result);
		}
		if (Is_inexacttrap_enabled()) {
			*dstptr = result;
			return(INEXACTEXCEPTION);
		}
		else Set_inexactflag();
	}
	*dstptr = result;
	return(NOEXCEPTION);
}

/*
 *  Single Fixed-point to Double Floating-point 
 */

int
sgl_to_dbl_fcnvxf(
		    int *srcptr,
		    unsigned int *nullptr,
		    dbl_floating_point *dstptr,
		    unsigned int *status)
{
	register int src, dst_exponent;
	register unsigned int resultp1 = 0, resultp2 = 0;

	src = *srcptr;
	/* 
	 * set sign bit of result and get magnitude of source 
	 */
	if (src < 0) {
		Dbl_setone_sign(resultp1);  
		Int_negate(src);
	}
	else {
		Dbl_setzero_sign(resultp1);
        	/* Check for zero */
        	if (src == 0) {
                	Dbl_setzero(resultp1,resultp2);
                	Dbl_copytoptr(resultp1,resultp2,dstptr);
                	return(NOEXCEPTION);
        	}
	}
	/*
	 * Generate exponent and normalized mantissa
	 */
	dst_exponent = 16;    /* initialize for normalization */
	/*
	 * Check word for most significant bit set.  Returns
	 * a value in dst_exponent indicating the bit position,
	 * between -1 and 30.
	 */
	Find_ms_one_bit(src,dst_exponent);
	/*  left justify source, with msb at bit position 1  */
	if (dst_exponent >= 0) src <<= dst_exponent;
	else src = 1 << 30;
	Dbl_set_mantissap1(resultp1, src >> DBL_EXP_LENGTH - 1);
	Dbl_set_mantissap2(resultp2, src << (33-DBL_EXP_LENGTH));
	Dbl_set_exponent(resultp1, (30+DBL_BIAS) - dst_exponent);
	Dbl_copytoptr(resultp1,resultp2,dstptr);
	return(NOEXCEPTION);
}

/*
 *  Double Fixed-point to Single Floating-point 
 */

int
dbl_to_sgl_fcnvxf(
			dbl_integer *srcptr,
			unsigned int *nullptr,
			sgl_floating_point *dstptr,
			unsigned int *status)
{
	int dst_exponent, srcp1;
	unsigned int result = 0, srcp2;

	Dint_copyfromptr(srcptr,srcp1,srcp2);
	/* 
	 * set sign bit of result and get magnitude of source 
	 */
	if (srcp1 < 0) {
		Sgl_setone_sign(result);  
		Dint_negate(srcp1,srcp2);
	}
	else {
		Sgl_setzero_sign(result);
        	/* Check for zero */
        	if (srcp1 == 0 && srcp2 == 0) {
                	Sgl_setzero(result);
                	*dstptr = result;
                	return(NOEXCEPTION);
		}
        }
	/*
	 * Generate exponent and normalized mantissa
	 */
	dst_exponent = 16;    /* initialize for normalization */
	if (srcp1 == 0) {
		/*
		 * Check word for most significant bit set.  Returns
		 * a value in dst_exponent indicating the bit position,
		 * between -1 and 30.
		 */
		Find_ms_one_bit(srcp2,dst_exponent);
		/*  left justify source, with msb at bit position 1  */
		if (dst_exponent >= 0) {
			srcp1 = srcp2 << dst_exponent;    
			srcp2 = 0;
		}
		else {
			srcp1 = srcp2 >> 1;
			srcp2 <<= 31; 
		}
		/*
		 *  since msb set is in second word, need to 
		 *  adjust bit position count
		 */
		dst_exponent += 32;
	}
	else {
		/*
		 * Check word for most significant bit set.  Returns
		 * a value in dst_exponent indicating the bit position,
		 * between -1 and 30.
		 *
		 */
		Find_ms_one_bit(srcp1,dst_exponent);
		/*  left justify source, with msb at bit position 1  */
		if (dst_exponent > 0) {
			Variable_shift_double(srcp1,srcp2,(32-dst_exponent),
			 srcp1); 
			srcp2 <<= dst_exponent;
		}
		/*
		 * If dst_exponent = 0, we don't need to shift anything.
		 * If dst_exponent = -1, src = - 2**63 so we won't need to 
		 * shift srcp2.
		 */
		else srcp1 >>= -(dst_exponent);
	}
	Sgl_set_mantissa(result, srcp1 >> SGL_EXP_LENGTH - 1);
	Sgl_set_exponent(result, (62+SGL_BIAS) - dst_exponent);

	/* check for inexact */
	if (Dint_isinexact_to_sgl(srcp1,srcp2)) {
		switch (Rounding_mode()) {
			case ROUNDPLUS: 
				if (Sgl_iszero_sign(result)) 
					Sgl_increment(result);
				break;
			case ROUNDMINUS: 
				if (Sgl_isone_sign(result)) 
					Sgl_increment(result);
				break;
			case ROUNDNEAREST:
				Sgl_roundnearest_from_dint(srcp1,srcp2,result);
		}
		if (Is_inexacttrap_enabled()) {
			*dstptr = result;
			return(INEXACTEXCEPTION);
		}
		else Set_inexactflag();
	}
	*dstptr = result;
	return(NOEXCEPTION);
}

/*
 *  Double Fixed-point to Double Floating-point 
 */

int
dbl_to_dbl_fcnvxf(
		    dbl_integer *srcptr,
		    unsigned int *nullptr,
		    dbl_floating_point *dstptr,
		    unsigned int *status)
{
	register int srcp1, dst_exponent;
	register unsigned int srcp2, resultp1 = 0, resultp2 = 0;

	Dint_copyfromptr(srcptr,srcp1,srcp2);
	/* 
	 * set sign bit of result and get magnitude of source 
	 */
	if (srcp1 < 0) {
		Dbl_setone_sign(resultp1);
		Dint_negate(srcp1,srcp2);
	}
	else {
		Dbl_setzero_sign(resultp1);
        	/* Check for zero */
        	if (srcp1 == 0 && srcp2 ==0) {
                	Dbl_setzero(resultp1,resultp2);
                	Dbl_copytoptr(resultp1,resultp2,dstptr);
                	return(NOEXCEPTION);
		}
        }
	/*
	 * Generate exponent and normalized mantissa
	 */
	dst_exponent = 16;    /* initialize for normalization */
	if (srcp1 == 0) {
		/*
		 * Check word for most significant bit set.  Returns
		 * a value in dst_exponent indicating the bit position,
		 * between -1 and 30.
		 */
		Find_ms_one_bit(srcp2,dst_exponent);
		/*  left justify source, with msb at bit position 1  */
		if (dst_exponent >= 0) {
			srcp1 = srcp2 << dst_exponent;    
			srcp2 = 0;
		}
		else {
			srcp1 = srcp2 >> 1;
			srcp2 <<= 31;
		}
		/*
		 *  since msb set is in second word, need to 
		 *  adjust bit position count
		 */
		dst_exponent += 32;
	}
	else {
		/*
		 * Check word for most significant bit set.  Returns
		 * a value in dst_exponent indicating the bit position,
		 * between -1 and 30.
		 */
		Find_ms_one_bit(srcp1,dst_exponent);
		/*  left justify source, with msb at bit position 1  */
		if (dst_exponent > 0) {
			Variable_shift_double(srcp1,srcp2,(32-dst_exponent),
			 srcp1); 
			srcp2 <<= dst_exponent;
		}
		/*
		 * If dst_exponent = 0, we don't need to shift anything.
		 * If dst_exponent = -1, src = - 2**63 so we won't need to 
		 * shift srcp2.
		 */
		else srcp1 >>= -(dst_exponent);
	}
	Dbl_set_mantissap1(resultp1, srcp1 >> (DBL_EXP_LENGTH-1));
	Shiftdouble(srcp1,srcp2,DBL_EXP_LENGTH-1,resultp2);
	Dbl_set_exponent(resultp1, (62+DBL_BIAS) - dst_exponent);

	/* check for inexact */
	if (Dint_isinexact_to_dbl(srcp2)) {
		switch (Rounding_mode()) {
			case ROUNDPLUS: 
				if (Dbl_iszero_sign(resultp1)) {
					Dbl_increment(resultp1,resultp2);
				}
				break;
			case ROUNDMINUS: 
				if (Dbl_isone_sign(resultp1)) {
					Dbl_increment(resultp1,resultp2);
				}
				break;
			case ROUNDNEAREST:
				Dbl_roundnearest_from_dint(srcp2,resultp1,
				resultp2);
		}
		if (Is_inexacttrap_enabled()) {
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(INEXACTEXCEPTION);
		}
		else Set_inexactflag();
	}
	Dbl_copytoptr(resultp1,resultp2,dstptr);
	return(NOEXCEPTION);
}