Mercurial > hg > CbC > CbC_gcc
comparison gcc/config/spu/divv2df3.c @ 0:a06113de4d67
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author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
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date | Fri, 17 Jul 2009 14:47:48 +0900 |
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1 /* Copyright (C) 2009 Free Software Foundation, Inc. | |
2 | |
3 This file is free software; you can redistribute it and/or modify it under | |
4 the terms of the GNU General Public License as published by the Free | |
5 Software Foundation; either version 3 of the License, or (at your option) | |
6 any later version. | |
7 | |
8 This file is distributed in the hope that it will be useful, but WITHOUT | |
9 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
11 for more details. | |
12 | |
13 Under Section 7 of GPL version 3, you are granted additional | |
14 permissions described in the GCC Runtime Library Exception, version | |
15 3.1, as published by the Free Software Foundation. | |
16 | |
17 You should have received a copy of the GNU General Public License and | |
18 a copy of the GCC Runtime Library Exception along with this program; | |
19 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
20 <http://www.gnu.org/licenses/>. */ | |
21 | |
22 #include <spu_intrinsics.h> | |
23 | |
24 vector double __divv2df3 (vector double a_in, vector double b_in); | |
25 | |
26 /* __divv2df3 divides the vector dividend a by the vector divisor b and | |
27 returns the resulting vector quotient. Maximum error about 0.5 ulp | |
28 over entire double range including denorms, compared to true result | |
29 in round-to-nearest rounding mode. Handles Inf or NaN operands and | |
30 results correctly. */ | |
31 | |
32 vector double | |
33 __divv2df3 (vector double a_in, vector double b_in) | |
34 { | |
35 /* Variables */ | |
36 vec_int4 exp, exp_bias; | |
37 vec_uint4 no_underflow, overflow; | |
38 vec_float4 mant_bf, inv_bf; | |
39 vec_ullong2 exp_a, exp_b; | |
40 vec_ullong2 a_nan, a_zero, a_inf, a_denorm, a_denorm0; | |
41 vec_ullong2 b_nan, b_zero, b_inf, b_denorm, b_denorm0; | |
42 vec_ullong2 nan; | |
43 vec_uint4 a_exp, b_exp; | |
44 vec_ullong2 a_mant_0, b_mant_0; | |
45 vec_ullong2 a_exp_1s, b_exp_1s; | |
46 vec_ullong2 sign_exp_mask; | |
47 | |
48 vec_double2 a, b; | |
49 vec_double2 mant_a, mant_b, inv_b, q0, q1, q2, mult; | |
50 | |
51 /* Constants */ | |
52 vec_uint4 exp_mask_u32 = spu_splats((unsigned int)0x7FF00000); | |
53 vec_uchar16 splat_hi = (vec_uchar16){0,1,2,3, 0,1,2,3, 8, 9,10,11, 8,9,10,11}; | |
54 vec_uchar16 swap_32 = (vec_uchar16){4,5,6,7, 0,1,2,3, 12,13,14,15, 8,9,10,11}; | |
55 vec_ullong2 exp_mask = spu_splats(0x7FF0000000000000ULL); | |
56 vec_ullong2 sign_mask = spu_splats(0x8000000000000000ULL); | |
57 vec_float4 onef = spu_splats(1.0f); | |
58 vec_double2 one = spu_splats(1.0); | |
59 vec_double2 exp_53 = (vec_double2)spu_splats(0x0350000000000000ULL); | |
60 | |
61 sign_exp_mask = spu_or(sign_mask, exp_mask); | |
62 | |
63 /* Extract the floating point components from each of the operands including | |
64 * exponent and mantissa. | |
65 */ | |
66 a_exp = (vec_uint4)spu_and((vec_uint4)a_in, exp_mask_u32); | |
67 a_exp = spu_shuffle(a_exp, a_exp, splat_hi); | |
68 b_exp = (vec_uint4)spu_and((vec_uint4)b_in, exp_mask_u32); | |
69 b_exp = spu_shuffle(b_exp, b_exp, splat_hi); | |
70 | |
71 a_mant_0 = (vec_ullong2)spu_cmpeq((vec_uint4)spu_andc((vec_ullong2)a_in, sign_exp_mask), 0); | |
72 a_mant_0 = spu_and(a_mant_0, spu_shuffle(a_mant_0, a_mant_0, swap_32)); | |
73 | |
74 b_mant_0 = (vec_ullong2)spu_cmpeq((vec_uint4)spu_andc((vec_ullong2)b_in, sign_exp_mask), 0); | |
75 b_mant_0 = spu_and(b_mant_0, spu_shuffle(b_mant_0, b_mant_0, swap_32)); | |
76 | |
77 a_exp_1s = (vec_ullong2)spu_cmpeq(a_exp, exp_mask_u32); | |
78 b_exp_1s = (vec_ullong2)spu_cmpeq(b_exp, exp_mask_u32); | |
79 | |
80 /* Identify all possible special values that must be accomodated including: | |
81 * +-denorm, +-0, +-infinity, and NaNs. | |
82 */ | |
83 a_denorm0= (vec_ullong2)spu_cmpeq(a_exp, 0); | |
84 a_nan = spu_andc(a_exp_1s, a_mant_0); | |
85 a_zero = spu_and (a_denorm0, a_mant_0); | |
86 a_inf = spu_and (a_exp_1s, a_mant_0); | |
87 a_denorm = spu_andc(a_denorm0, a_zero); | |
88 | |
89 b_denorm0= (vec_ullong2)spu_cmpeq(b_exp, 0); | |
90 b_nan = spu_andc(b_exp_1s, b_mant_0); | |
91 b_zero = spu_and (b_denorm0, b_mant_0); | |
92 b_inf = spu_and (b_exp_1s, b_mant_0); | |
93 b_denorm = spu_andc(b_denorm0, b_zero); | |
94 | |
95 /* Scale denorm inputs to into normalized numbers by conditionally scaling the | |
96 * input parameters. | |
97 */ | |
98 a = spu_sub(spu_or(a_in, exp_53), spu_sel(exp_53, a_in, sign_mask)); | |
99 a = spu_sel(a_in, a, a_denorm); | |
100 | |
101 b = spu_sub(spu_or(b_in, exp_53), spu_sel(exp_53, b_in, sign_mask)); | |
102 b = spu_sel(b_in, b, b_denorm); | |
103 | |
104 /* Extract the divisor and dividend exponent and force parameters into the signed | |
105 * range [1.0,2.0) or [-1.0,2.0). | |
106 */ | |
107 exp_a = spu_and((vec_ullong2)a, exp_mask); | |
108 exp_b = spu_and((vec_ullong2)b, exp_mask); | |
109 | |
110 mant_a = spu_sel(a, one, (vec_ullong2)exp_mask); | |
111 mant_b = spu_sel(b, one, (vec_ullong2)exp_mask); | |
112 | |
113 /* Approximate the single reciprocal of b by using | |
114 * the single precision reciprocal estimate followed by one | |
115 * single precision iteration of Newton-Raphson. | |
116 */ | |
117 mant_bf = spu_roundtf(mant_b); | |
118 inv_bf = spu_re(mant_bf); | |
119 inv_bf = spu_madd(spu_nmsub(mant_bf, inv_bf, onef), inv_bf, inv_bf); | |
120 | |
121 /* Perform 2 more Newton-Raphson iterations in double precision. The | |
122 * result (q1) is in the range (0.5, 2.0). | |
123 */ | |
124 inv_b = spu_extend(inv_bf); | |
125 inv_b = spu_madd(spu_nmsub(mant_b, inv_b, one), inv_b, inv_b); | |
126 q0 = spu_mul(mant_a, inv_b); | |
127 q1 = spu_madd(spu_nmsub(mant_b, q0, mant_a), inv_b, q0); | |
128 | |
129 /* Determine the exponent correction factor that must be applied | |
130 * to q1 by taking into account the exponent of the normalized inputs | |
131 * and the scale factors that were applied to normalize them. | |
132 */ | |
133 exp = spu_rlmaska(spu_sub((vec_int4)exp_a, (vec_int4)exp_b), -20); | |
134 exp = spu_add(exp, (vec_int4)spu_add(spu_and((vec_int4)a_denorm, -0x34), spu_and((vec_int4)b_denorm, 0x34))); | |
135 | |
136 /* Bias the quotient exponent depending on the sign of the exponent correction | |
137 * factor so that a single multiplier will ensure the entire double precision | |
138 * domain (including denorms) can be achieved. | |
139 * | |
140 * exp bias q1 adjust exp | |
141 * ===== ======== ========== | |
142 * positive 2^+65 -65 | |
143 * negative 2^-64 +64 | |
144 */ | |
145 exp_bias = spu_xor(spu_rlmaska(exp, -31), 64); | |
146 exp = spu_sub(exp, exp_bias); | |
147 | |
148 q1 = spu_sel(q1, (vec_double2)spu_add((vec_int4)q1, spu_sl(exp_bias, 20)), exp_mask); | |
149 | |
150 /* Compute a multiplier (mult) to applied to the quotient (q1) to produce the | |
151 * expected result. On overflow, clamp the multiplier to the maximum non-infinite | |
152 * number in case the rounding mode is not round-to-nearest. | |
153 */ | |
154 exp = spu_add(exp, 0x3FF); | |
155 no_underflow = spu_cmpgt(exp, 0); | |
156 overflow = spu_cmpgt(exp, 0x7FE); | |
157 exp = spu_and(spu_sl(exp, 20), (vec_int4)no_underflow); | |
158 exp = spu_and(exp, (vec_int4)exp_mask); | |
159 | |
160 mult = spu_sel((vec_double2)exp, (vec_double2)(spu_add((vec_uint4)exp_mask, -1)), (vec_ullong2)overflow); | |
161 | |
162 /* Handle special value conditions. These include: | |
163 * | |
164 * 1) IF either operand is a NaN OR both operands are 0 or INFINITY THEN a NaN | |
165 * results. | |
166 * 2) ELSE IF the dividend is an INFINITY OR the divisor is 0 THEN a INFINITY results. | |
167 * 3) ELSE IF the dividend is 0 OR the divisor is INFINITY THEN a 0 results. | |
168 */ | |
169 mult = spu_andc(mult, (vec_double2)spu_or(a_zero, b_inf)); | |
170 mult = spu_sel(mult, (vec_double2)exp_mask, spu_or(a_inf, b_zero)); | |
171 | |
172 nan = spu_or(a_nan, b_nan); | |
173 nan = spu_or(nan, spu_and(a_zero, b_zero)); | |
174 nan = spu_or(nan, spu_and(a_inf, b_inf)); | |
175 | |
176 mult = spu_or(mult, (vec_double2)nan); | |
177 | |
178 /* Scale the final quotient */ | |
179 | |
180 q2 = spu_mul(q1, mult); | |
181 | |
182 return (q2); | |
183 } | |
184 | |
185 | |
186 /* We use the same function for vector and scalar division. Provide the | |
187 scalar entry point as an alias. */ | |
188 double __divdf3 (double a, double b) | |
189 __attribute__ ((__alias__ ("__divv2df3"))); | |
190 | |
191 /* Some toolchain builds used the __fast_divdf3 name for this helper function. | |
192 Provide this as another alternate entry point for compatibility. */ | |
193 double __fast_divdf3 (double a, double b) | |
194 __attribute__ ((__alias__ ("__divv2df3"))); | |
195 |