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comparison libgcc/config/libbid/bid32_to_bid128.c @ 0:a06113de4d67

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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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-1:000000000000 0:a06113de4d67
1 /* Copyright (C) 2007, 2009 Free Software Foundation, Inc.
2
3 This file is part of GCC.
4
5 GCC is free software; you can redistribute it and/or modify it under
6 the terms of the GNU General Public License as published by the Free
7 Software Foundation; either version 3, or (at your option) any later
8 version.
9
10 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
11 WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 for more details.
14
15 Under Section 7 of GPL version 3, you are granted additional
16 permissions described in the GCC Runtime Library Exception, version
17 3.1, as published by the Free Software Foundation.
18
19 You should have received a copy of the GNU General Public License and
20 a copy of the GCC Runtime Library Exception along with this program;
21 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
22 <http://www.gnu.org/licenses/>. */
23
24 #define BID_128RES
25 #include "bid_internal.h"
26
27 /*
28 * Takes a BID32 as input and converts it to a BID128 and returns it.
29 */
30 TYPE0_FUNCTION_ARGTYPE1_NORND (UINT128, bid32_to_bid128, UINT32, x)
31
32 UINT128 new_coeff, res;
33 UINT32 sign_x;
34 int exponent_x;
35 UINT32 coefficient_x;
36
37 if (!unpack_BID32 (&sign_x, &exponent_x, &coefficient_x, x)) {
38 if (((x) & 0x78000000) == 0x78000000) {
39 #ifdef SET_STATUS_FLAGS
40 if (((x) & 0x7e000000) == 0x7e000000) // sNaN
41 __set_status_flags (pfpsf, INVALID_EXCEPTION);
42 #endif
43 res.w[0] = (coefficient_x & 0x000fffff);
44 __mul_64x128_low (res, res.w[0], power10_table_128[27]);
45 res.w[1] |=
46 ((((UINT64) coefficient_x) << 32) & 0xfc00000000000000ull);
47
48 BID_RETURN (res);
49 }
50 }
51
52 new_coeff.w[0] = coefficient_x;
53 new_coeff.w[1] = 0;
54 get_BID128_very_fast (&res, ((UINT64) sign_x) << 32,
55 exponent_x + DECIMAL_EXPONENT_BIAS_128 -
56 DECIMAL_EXPONENT_BIAS_32, new_coeff);
57 BID_RETURN (res);
58 } // convert_bid32_to_bid128
59
60
61 /*
62 * Takes a BID128 as input and converts it to a BID32 and returns it.
63 */
64 #if DECIMAL_CALL_BY_REFERENCE
65
66 void
67 bid128_to_bid32 (UINT32 * pres,
68 UINT128 *
69 px _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
70 _EXC_INFO_PARAM) {
71 UINT128 x = *px;
72 #else
73
74 UINT32
75 bid128_to_bid32 (UINT128 x _RND_MODE_PARAM _EXC_FLAGS_PARAM
76 _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
77 #endif
78 UINT128 CX, T128, TP128, Qh, Ql, Qh1, Stemp, Tmp, Tmp1, CX1;
79 UINT64 sign_x, carry, cy;
80 SINT64 D;
81 UINT32 res;
82 int_float f64, fx;
83 int exponent_x, extra_digits, amount, bin_expon_cx, uf_check = 0;
84 unsigned rmode, status;
85
86 #if DECIMAL_CALL_BY_REFERENCE
87 #if !DECIMAL_GLOBAL_ROUNDING
88 _IDEC_round rnd_mode = *prnd_mode;
89 #endif
90 #endif
91
92 BID_SWAP128 (x);
93 // unpack arguments, check for NaN or Infinity or 0
94 if (!unpack_BID128_value (&sign_x, &exponent_x, &CX, x)) {
95 if (((x.w[1]) & 0x7800000000000000ull) == 0x7800000000000000ull) {
96 Tmp.w[1] = (CX.w[1] & 0x00003fffffffffffull);
97 Tmp.w[0] = CX.w[0];
98 TP128 = reciprocals10_128[27];
99 __mul_128x128_full (Qh, Ql, Tmp, TP128);
100 amount = recip_scale[27] - 64;
101 res = ((CX.w[1] >> 32) & 0xfc000000) | (Qh.w[1] >> amount);
102 #ifdef SET_STATUS_FLAGS
103 if ((x.w[1] & SNAN_MASK64) == SNAN_MASK64) // sNaN
104 __set_status_flags (pfpsf, INVALID_EXCEPTION);
105 #endif
106 BID_RETURN_VAL (res);
107 }
108 // x is 0
109 exponent_x =
110 exponent_x - DECIMAL_EXPONENT_BIAS_128 + DECIMAL_EXPONENT_BIAS_32;
111 if (exponent_x < 0)
112 exponent_x = 0;
113 if (exponent_x > DECIMAL_MAX_EXPON_32)
114 exponent_x = DECIMAL_MAX_EXPON_32;
115 res = (sign_x >> 32) | (exponent_x << 23);
116 BID_RETURN_VAL (res);
117
118 }
119
120 if (CX.w[1] || (CX.w[0] >= 10000000)) {
121 // find number of digits in coefficient
122 // 2^64
123 f64.i = 0x5f800000;
124 // fx ~ CX
125 fx.d = (float) CX.w[1] * f64.d + (float) CX.w[0];
126 bin_expon_cx = ((fx.i >> 23) & 0xff) - 0x7f;
127 extra_digits = estimate_decimal_digits[bin_expon_cx] - 7;
128 // scale = 38-estimate_decimal_digits[bin_expon_cx];
129 D = CX.w[1] - power10_index_binexp_128[bin_expon_cx].w[1];
130 if (D > 0
131 || (!D
132 && CX.w[0] >= power10_index_binexp_128[bin_expon_cx].w[0]))
133 extra_digits++;
134
135 exponent_x += extra_digits;
136
137 #ifndef IEEE_ROUND_NEAREST_TIES_AWAY
138 #ifndef IEEE_ROUND_NEAREST
139 rmode = rnd_mode;
140 if (sign_x && (unsigned) (rmode - 1) < 2)
141 rmode = 3 - rmode;
142 #else
143 rmode = 0;
144 #endif
145 #else
146 rmode = 0;
147 #endif
148 if (exponent_x <
149 DECIMAL_EXPONENT_BIAS_128 - DECIMAL_EXPONENT_BIAS_32) {
150 uf_check = 1;
151 if (-extra_digits + exponent_x - DECIMAL_EXPONENT_BIAS_128 +
152 DECIMAL_EXPONENT_BIAS_32 + 35 >= 0) {
153 if (exponent_x ==
154 DECIMAL_EXPONENT_BIAS_128 - DECIMAL_EXPONENT_BIAS_32 - 1) {
155 T128 = round_const_table_128[rmode][extra_digits];
156 __add_carry_out (CX1.w[0], carry, T128.w[0], CX.w[0]);
157 CX1.w[1] = CX.w[1] + T128.w[1] + carry;
158 if (__unsigned_compare_ge_128
159 (CX1, power10_table_128[extra_digits + 7]))
160 uf_check = 0;
161 }
162 extra_digits =
163 extra_digits + DECIMAL_EXPONENT_BIAS_128 -
164 DECIMAL_EXPONENT_BIAS_32 - exponent_x;
165 exponent_x =
166 DECIMAL_EXPONENT_BIAS_128 - DECIMAL_EXPONENT_BIAS_32;
167 } else
168 rmode = ROUNDING_TO_ZERO;
169 }
170
171 T128 = round_const_table_128[rmode][extra_digits];
172 __add_carry_out (CX.w[0], carry, T128.w[0], CX.w[0]);
173 CX.w[1] = CX.w[1] + T128.w[1] + carry;
174
175 TP128 = reciprocals10_128[extra_digits];
176 __mul_128x128_full (Qh, Ql, CX, TP128);
177 amount = recip_scale[extra_digits];
178
179 if (amount >= 64) {
180 CX.w[0] = Qh.w[1] >> (amount - 64);
181 CX.w[1] = 0;
182 } else {
183 __shr_128 (CX, Qh, amount);
184 }
185
186 #ifndef IEEE_ROUND_NEAREST_TIES_AWAY
187 #ifndef IEEE_ROUND_NEAREST
188 if (!(rnd_mode))
189 #endif
190 if (CX.w[0] & 1) {
191 // check whether fractional part of initial_P/10^ed1 is exactly .5
192
193 // get remainder
194 __shl_128_long (Qh1, Qh, (128 - amount));
195
196 if (!Qh1.w[1] && !Qh1.w[0]
197 && (Ql.w[1] < reciprocals10_128[extra_digits].w[1]
198 || (Ql.w[1] == reciprocals10_128[extra_digits].w[1]
199 && Ql.w[0] < reciprocals10_128[extra_digits].w[0]))) {
200 CX.w[0]--;
201 }
202 }
203 #endif
204
205
206 {
207 status = INEXACT_EXCEPTION;
208 // get remainder
209 __shl_128_long (Qh1, Qh, (128 - amount));
210
211 switch (rmode) {
212 case ROUNDING_TO_NEAREST:
213 case ROUNDING_TIES_AWAY:
214 // test whether fractional part is 0
215 if (Qh1.w[1] == 0x8000000000000000ull && (!Qh1.w[0])
216 && (Ql.w[1] < reciprocals10_128[extra_digits].w[1]
217 || (Ql.w[1] == reciprocals10_128[extra_digits].w[1]
218 && Ql.w[0] < reciprocals10_128[extra_digits].w[0])))
219 status = EXACT_STATUS;
220 break;
221 case ROUNDING_DOWN:
222 case ROUNDING_TO_ZERO:
223 if ((!Qh1.w[1]) && (!Qh1.w[0])
224 && (Ql.w[1] < reciprocals10_128[extra_digits].w[1]
225 || (Ql.w[1] == reciprocals10_128[extra_digits].w[1]
226 && Ql.w[0] < reciprocals10_128[extra_digits].w[0])))
227 status = EXACT_STATUS;
228 break;
229 default:
230 // round up
231 __add_carry_out (Stemp.w[0], cy, Ql.w[0],
232 reciprocals10_128[extra_digits].w[0]);
233 __add_carry_in_out (Stemp.w[1], carry, Ql.w[1],
234 reciprocals10_128[extra_digits].w[1], cy);
235 __shr_128_long (Qh, Qh1, (128 - amount));
236 Tmp.w[0] = 1;
237 Tmp.w[1] = 0;
238 __shl_128_long (Tmp1, Tmp, amount);
239 Qh.w[0] += carry;
240 if (Qh.w[0] < carry)
241 Qh.w[1]++;
242 if (__unsigned_compare_ge_128 (Qh, Tmp1))
243 status = EXACT_STATUS;
244 }
245
246 if (status != EXACT_STATUS) {
247 if (uf_check) {
248 status |= UNDERFLOW_EXCEPTION;
249 }
250 #ifdef SET_STATUS_FLAGS
251 __set_status_flags (pfpsf, status);
252 #endif
253 }
254 }
255
256 }
257
258 res =
259 get_BID32 ((UINT32) (sign_x >> 32),
260 exponent_x - DECIMAL_EXPONENT_BIAS_128 +
261 DECIMAL_EXPONENT_BIAS_32, CX.w[0], rnd_mode, pfpsf);
262 BID_RETURN_VAL (res);
263
264 }