Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Basic one-word fraction declaration and manipulation. | |
3 | */ | |
4 | ||
5 | #define _FP_FRAC_DECL_1(X) _FP_W_TYPE X##_f | |
6 | #define _FP_FRAC_COPY_1(D,S) (D##_f = S##_f) | |
7 | #define _FP_FRAC_SET_1(X,I) (X##_f = I) | |
8 | #define _FP_FRAC_HIGH_1(X) (X##_f) | |
9 | #define _FP_FRAC_LOW_1(X) (X##_f) | |
10 | #define _FP_FRAC_WORD_1(X,w) (X##_f) | |
11 | ||
12 | #define _FP_FRAC_ADDI_1(X,I) (X##_f += I) | |
13 | #define _FP_FRAC_SLL_1(X,N) \ | |
14 | do { \ | |
15 | if (__builtin_constant_p(N) && (N) == 1) \ | |
16 | X##_f += X##_f; \ | |
17 | else \ | |
18 | X##_f <<= (N); \ | |
19 | } while (0) | |
20 | #define _FP_FRAC_SRL_1(X,N) (X##_f >>= N) | |
21 | ||
22 | /* Right shift with sticky-lsb. */ | |
23 | #define _FP_FRAC_SRS_1(X,N,sz) __FP_FRAC_SRS_1(X##_f, N, sz) | |
24 | ||
25 | #define __FP_FRAC_SRS_1(X,N,sz) \ | |
26 | (X = (X >> (N) | (__builtin_constant_p(N) && (N) == 1 \ | |
27 | ? X & 1 : (X << (_FP_W_TYPE_SIZE - (N))) != 0))) | |
28 | ||
29 | #define _FP_FRAC_ADD_1(R,X,Y) (R##_f = X##_f + Y##_f) | |
30 | #define _FP_FRAC_SUB_1(R,X,Y) (R##_f = X##_f - Y##_f) | |
31 | #define _FP_FRAC_CLZ_1(z, X) __FP_CLZ(z, X##_f) | |
32 | ||
33 | /* Predicates */ | |
34 | #define _FP_FRAC_NEGP_1(X) ((_FP_WS_TYPE)X##_f < 0) | |
35 | #define _FP_FRAC_ZEROP_1(X) (X##_f == 0) | |
36 | #define _FP_FRAC_OVERP_1(fs,X) (X##_f & _FP_OVERFLOW_##fs) | |
37 | #define _FP_FRAC_EQ_1(X, Y) (X##_f == Y##_f) | |
38 | #define _FP_FRAC_GE_1(X, Y) (X##_f >= Y##_f) | |
39 | #define _FP_FRAC_GT_1(X, Y) (X##_f > Y##_f) | |
40 | ||
41 | #define _FP_ZEROFRAC_1 0 | |
42 | #define _FP_MINFRAC_1 1 | |
43 | ||
44 | /* | |
45 | * Unpack the raw bits of a native fp value. Do not classify or | |
46 | * normalize the data. | |
47 | */ | |
48 | ||
49 | #define _FP_UNPACK_RAW_1(fs, X, val) \ | |
50 | do { \ | |
51 | union _FP_UNION_##fs _flo; _flo.flt = (val); \ | |
52 | \ | |
53 | X##_f = _flo.bits.frac; \ | |
54 | X##_e = _flo.bits.exp; \ | |
55 | X##_s = _flo.bits.sign; \ | |
56 | } while (0) | |
57 | ||
58 | ||
59 | /* | |
60 | * Repack the raw bits of a native fp value. | |
61 | */ | |
62 | ||
63 | #define _FP_PACK_RAW_1(fs, val, X) \ | |
64 | do { \ | |
65 | union _FP_UNION_##fs _flo; \ | |
66 | \ | |
67 | _flo.bits.frac = X##_f; \ | |
68 | _flo.bits.exp = X##_e; \ | |
69 | _flo.bits.sign = X##_s; \ | |
70 | \ | |
71 | (val) = _flo.flt; \ | |
72 | } while (0) | |
73 | ||
74 | ||
75 | /* | |
76 | * Multiplication algorithms: | |
77 | */ | |
78 | ||
79 | /* Basic. Assuming the host word size is >= 2*FRACBITS, we can do the | |
80 | multiplication immediately. */ | |
81 | ||
82 | #define _FP_MUL_MEAT_1_imm(fs, R, X, Y) \ | |
83 | do { \ | |
84 | R##_f = X##_f * Y##_f; \ | |
85 | /* Normalize since we know where the msb of the multiplicands \ | |
86 | were (bit B), we know that the msb of the of the product is \ | |
87 | at either 2B or 2B-1. */ \ | |
88 | _FP_FRAC_SRS_1(R, _FP_WFRACBITS_##fs-1, 2*_FP_WFRACBITS_##fs); \ | |
89 | } while (0) | |
90 | ||
91 | /* Given a 1W * 1W => 2W primitive, do the extended multiplication. */ | |
92 | ||
93 | #define _FP_MUL_MEAT_1_wide(fs, R, X, Y, doit) \ | |
94 | do { \ | |
95 | _FP_W_TYPE _Z_f0, _Z_f1; \ | |
96 | doit(_Z_f1, _Z_f0, X##_f, Y##_f); \ | |
97 | /* Normalize since we know where the msb of the multiplicands \ | |
98 | were (bit B), we know that the msb of the of the product is \ | |
99 | at either 2B or 2B-1. */ \ | |
100 | _FP_FRAC_SRS_2(_Z, _FP_WFRACBITS_##fs-1, 2*_FP_WFRACBITS_##fs); \ | |
101 | R##_f = _Z_f0; \ | |
102 | } while (0) | |
103 | ||
104 | /* Finally, a simple widening multiply algorithm. What fun! */ | |
105 | ||
106 | #define _FP_MUL_MEAT_1_hard(fs, R, X, Y) \ | |
107 | do { \ | |
108 | _FP_W_TYPE _xh, _xl, _yh, _yl, _z_f0, _z_f1, _a_f0, _a_f1; \ | |
109 | \ | |
110 | /* split the words in half */ \ | |
111 | _xh = X##_f >> (_FP_W_TYPE_SIZE/2); \ | |
112 | _xl = X##_f & (((_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2)) - 1); \ | |
113 | _yh = Y##_f >> (_FP_W_TYPE_SIZE/2); \ | |
114 | _yl = Y##_f & (((_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2)) - 1); \ | |
115 | \ | |
116 | /* multiply the pieces */ \ | |
117 | _z_f0 = _xl * _yl; \ | |
118 | _a_f0 = _xh * _yl; \ | |
119 | _a_f1 = _xl * _yh; \ | |
120 | _z_f1 = _xh * _yh; \ | |
121 | \ | |
122 | /* reassemble into two full words */ \ | |
123 | if ((_a_f0 += _a_f1) < _a_f1) \ | |
124 | _z_f1 += (_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2); \ | |
125 | _a_f1 = _a_f0 >> (_FP_W_TYPE_SIZE/2); \ | |
126 | _a_f0 = _a_f0 << (_FP_W_TYPE_SIZE/2); \ | |
127 | _FP_FRAC_ADD_2(_z, _z, _a); \ | |
128 | \ | |
129 | /* normalize */ \ | |
130 | _FP_FRAC_SRS_2(_z, _FP_WFRACBITS_##fs - 1, 2*_FP_WFRACBITS_##fs); \ | |
131 | R##_f = _z_f0; \ | |
132 | } while (0) | |
133 | ||
134 | ||
135 | /* | |
136 | * Division algorithms: | |
137 | */ | |
138 | ||
139 | /* Basic. Assuming the host word size is >= 2*FRACBITS, we can do the | |
140 | division immediately. Give this macro either _FP_DIV_HELP_imm for | |
141 | C primitives or _FP_DIV_HELP_ldiv for the ISO function. Which you | |
142 | choose will depend on what the compiler does with divrem4. */ | |
143 | ||
144 | #define _FP_DIV_MEAT_1_imm(fs, R, X, Y, doit) \ | |
145 | do { \ | |
146 | _FP_W_TYPE _q, _r; \ | |
147 | X##_f <<= (X##_f < Y##_f \ | |
148 | ? R##_e--, _FP_WFRACBITS_##fs \ | |
149 | : _FP_WFRACBITS_##fs - 1); \ | |
150 | doit(_q, _r, X##_f, Y##_f); \ | |
151 | R##_f = _q | (_r != 0); \ | |
152 | } while (0) | |
153 | ||
154 | /* GCC's longlong.h defines a 2W / 1W => (1W,1W) primitive udiv_qrnnd | |
155 | that may be useful in this situation. This first is for a primitive | |
156 | that requires normalization, the second for one that does not. Look | |
157 | for UDIV_NEEDS_NORMALIZATION to tell which your machine needs. */ | |
158 | ||
159 | #define _FP_DIV_MEAT_1_udiv_norm(fs, R, X, Y) \ | |
160 | do { \ | |
161 | _FP_W_TYPE _nh, _nl, _q, _r; \ | |
162 | \ | |
163 | /* Normalize Y -- i.e. make the most significant bit set. */ \ | |
164 | Y##_f <<= _FP_WFRACXBITS_##fs - 1; \ | |
165 | \ | |
166 | /* Shift X op correspondingly high, that is, up one full word. */ \ | |
167 | if (X##_f <= Y##_f) \ | |
168 | { \ | |
169 | _nl = 0; \ | |
170 | _nh = X##_f; \ | |
171 | } \ | |
172 | else \ | |
173 | { \ | |
174 | R##_e++; \ | |
175 | _nl = X##_f << (_FP_W_TYPE_SIZE-1); \ | |
176 | _nh = X##_f >> 1; \ | |
177 | } \ | |
178 | \ | |
179 | udiv_qrnnd(_q, _r, _nh, _nl, Y##_f); \ | |
180 | R##_f = _q | (_r != 0); \ | |
181 | } while (0) | |
182 | ||
183 | #define _FP_DIV_MEAT_1_udiv(fs, R, X, Y) \ | |
184 | do { \ | |
185 | _FP_W_TYPE _nh, _nl, _q, _r; \ | |
186 | if (X##_f < Y##_f) \ | |
187 | { \ | |
188 | R##_e--; \ | |
189 | _nl = X##_f << _FP_WFRACBITS_##fs; \ | |
190 | _nh = X##_f >> _FP_WFRACXBITS_##fs; \ | |
191 | } \ | |
192 | else \ | |
193 | { \ | |
194 | _nl = X##_f << (_FP_WFRACBITS_##fs - 1); \ | |
195 | _nh = X##_f >> (_FP_WFRACXBITS_##fs + 1); \ | |
196 | } \ | |
197 | udiv_qrnnd(_q, _r, _nh, _nl, Y##_f); \ | |
198 | R##_f = _q | (_r != 0); \ | |
199 | } while (0) | |
200 | ||
201 | ||
202 | /* | |
203 | * Square root algorithms: | |
204 | * We have just one right now, maybe Newton approximation | |
205 | * should be added for those machines where division is fast. | |
206 | */ | |
207 | ||
208 | #define _FP_SQRT_MEAT_1(R, S, T, X, q) \ | |
209 | do { \ | |
210 | while (q) \ | |
211 | { \ | |
212 | T##_f = S##_f + q; \ | |
213 | if (T##_f <= X##_f) \ | |
214 | { \ | |
215 | S##_f = T##_f + q; \ | |
216 | X##_f -= T##_f; \ | |
217 | R##_f += q; \ | |
218 | } \ | |
219 | _FP_FRAC_SLL_1(X, 1); \ | |
220 | q >>= 1; \ | |
221 | } \ | |
222 | } while (0) | |
223 | ||
224 | /* | |
225 | * Assembly/disassembly for converting to/from integral types. | |
226 | * No shifting or overflow handled here. | |
227 | */ | |
228 | ||
229 | #define _FP_FRAC_ASSEMBLE_1(r, X, rsize) (r = X##_f) | |
230 | #define _FP_FRAC_DISASSEMBLE_1(X, r, rsize) (X##_f = r) | |
231 | ||
232 | ||
233 | /* | |
234 | * Convert FP values between word sizes | |
235 | */ | |
236 | ||
237 | #define _FP_FRAC_CONV_1_1(dfs, sfs, D, S) \ | |
238 | do { \ | |
239 | D##_f = S##_f; \ | |
240 | if (_FP_WFRACBITS_##sfs > _FP_WFRACBITS_##dfs) \ | |
241 | _FP_FRAC_SRS_1(D, (_FP_WFRACBITS_##sfs-_FP_WFRACBITS_##dfs), \ | |
242 | _FP_WFRACBITS_##sfs); \ | |
243 | else \ | |
244 | D##_f <<= _FP_WFRACBITS_##dfs - _FP_WFRACBITS_##sfs; \ | |
245 | } while (0) |