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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* This has so very few changes over libgcc2's __udivmoddi4 it isn't funny. */ |
3 | ||
d2b194ed | 4 | #include <math-emu/soft-fp.h> |
1da177e4 LT |
5 | |
6 | #undef count_leading_zeros | |
7 | #define count_leading_zeros __FP_CLZ | |
8 | ||
9 | void | |
10 | _fp_udivmodti4(_FP_W_TYPE q[2], _FP_W_TYPE r[2], | |
11 | _FP_W_TYPE n1, _FP_W_TYPE n0, | |
12 | _FP_W_TYPE d1, _FP_W_TYPE d0) | |
13 | { | |
14 | _FP_W_TYPE q0, q1, r0, r1; | |
15 | _FP_I_TYPE b, bm; | |
16 | ||
17 | if (d1 == 0) | |
18 | { | |
19 | #if !UDIV_NEEDS_NORMALIZATION | |
20 | if (d0 > n1) | |
21 | { | |
22 | /* 0q = nn / 0D */ | |
23 | ||
24 | udiv_qrnnd (q0, n0, n1, n0, d0); | |
25 | q1 = 0; | |
26 | ||
27 | /* Remainder in n0. */ | |
28 | } | |
29 | else | |
30 | { | |
31 | /* qq = NN / 0d */ | |
32 | ||
33 | if (d0 == 0) | |
34 | d0 = 1 / d0; /* Divide intentionally by zero. */ | |
35 | ||
36 | udiv_qrnnd (q1, n1, 0, n1, d0); | |
37 | udiv_qrnnd (q0, n0, n1, n0, d0); | |
38 | ||
39 | /* Remainder in n0. */ | |
40 | } | |
41 | ||
42 | r0 = n0; | |
43 | r1 = 0; | |
44 | ||
45 | #else /* UDIV_NEEDS_NORMALIZATION */ | |
46 | ||
47 | if (d0 > n1) | |
48 | { | |
49 | /* 0q = nn / 0D */ | |
50 | ||
51 | count_leading_zeros (bm, d0); | |
52 | ||
53 | if (bm != 0) | |
54 | { | |
55 | /* Normalize, i.e. make the most significant bit of the | |
56 | denominator set. */ | |
57 | ||
58 | d0 = d0 << bm; | |
59 | n1 = (n1 << bm) | (n0 >> (_FP_W_TYPE_SIZE - bm)); | |
60 | n0 = n0 << bm; | |
61 | } | |
62 | ||
63 | udiv_qrnnd (q0, n0, n1, n0, d0); | |
64 | q1 = 0; | |
65 | ||
66 | /* Remainder in n0 >> bm. */ | |
67 | } | |
68 | else | |
69 | { | |
70 | /* qq = NN / 0d */ | |
71 | ||
72 | if (d0 == 0) | |
73 | d0 = 1 / d0; /* Divide intentionally by zero. */ | |
74 | ||
75 | count_leading_zeros (bm, d0); | |
76 | ||
77 | if (bm == 0) | |
78 | { | |
79 | /* From (n1 >= d0) /\ (the most significant bit of d0 is set), | |
80 | conclude (the most significant bit of n1 is set) /\ (the | |
81 | leading quotient digit q1 = 1). | |
82 | ||
83 | This special case is necessary, not an optimization. | |
84 | (Shifts counts of SI_TYPE_SIZE are undefined.) */ | |
85 | ||
86 | n1 -= d0; | |
87 | q1 = 1; | |
88 | } | |
89 | else | |
90 | { | |
91 | _FP_W_TYPE n2; | |
92 | ||
93 | /* Normalize. */ | |
94 | ||
95 | b = _FP_W_TYPE_SIZE - bm; | |
96 | ||
97 | d0 = d0 << bm; | |
98 | n2 = n1 >> b; | |
99 | n1 = (n1 << bm) | (n0 >> b); | |
100 | n0 = n0 << bm; | |
101 | ||
102 | udiv_qrnnd (q1, n1, n2, n1, d0); | |
103 | } | |
104 | ||
105 | /* n1 != d0... */ | |
106 | ||
107 | udiv_qrnnd (q0, n0, n1, n0, d0); | |
108 | ||
109 | /* Remainder in n0 >> bm. */ | |
110 | } | |
111 | ||
112 | r0 = n0 >> bm; | |
113 | r1 = 0; | |
114 | #endif /* UDIV_NEEDS_NORMALIZATION */ | |
115 | } | |
116 | else | |
117 | { | |
118 | if (d1 > n1) | |
119 | { | |
120 | /* 00 = nn / DD */ | |
121 | ||
122 | q0 = 0; | |
123 | q1 = 0; | |
124 | ||
125 | /* Remainder in n1n0. */ | |
126 | r0 = n0; | |
127 | r1 = n1; | |
128 | } | |
129 | else | |
130 | { | |
131 | /* 0q = NN / dd */ | |
132 | ||
133 | count_leading_zeros (bm, d1); | |
134 | if (bm == 0) | |
135 | { | |
136 | /* From (n1 >= d1) /\ (the most significant bit of d1 is set), | |
137 | conclude (the most significant bit of n1 is set) /\ (the | |
138 | quotient digit q0 = 0 or 1). | |
139 | ||
140 | This special case is necessary, not an optimization. */ | |
141 | ||
142 | /* The condition on the next line takes advantage of that | |
143 | n1 >= d1 (true due to program flow). */ | |
144 | if (n1 > d1 || n0 >= d0) | |
145 | { | |
146 | q0 = 1; | |
147 | sub_ddmmss (n1, n0, n1, n0, d1, d0); | |
148 | } | |
149 | else | |
150 | q0 = 0; | |
151 | ||
152 | q1 = 0; | |
153 | ||
154 | r0 = n0; | |
155 | r1 = n1; | |
156 | } | |
157 | else | |
158 | { | |
159 | _FP_W_TYPE m1, m0, n2; | |
160 | ||
161 | /* Normalize. */ | |
162 | ||
163 | b = _FP_W_TYPE_SIZE - bm; | |
164 | ||
165 | d1 = (d1 << bm) | (d0 >> b); | |
166 | d0 = d0 << bm; | |
167 | n2 = n1 >> b; | |
168 | n1 = (n1 << bm) | (n0 >> b); | |
169 | n0 = n0 << bm; | |
170 | ||
171 | udiv_qrnnd (q0, n1, n2, n1, d1); | |
172 | umul_ppmm (m1, m0, q0, d0); | |
173 | ||
174 | if (m1 > n1 || (m1 == n1 && m0 > n0)) | |
175 | { | |
176 | q0--; | |
177 | sub_ddmmss (m1, m0, m1, m0, d1, d0); | |
178 | } | |
179 | ||
180 | q1 = 0; | |
181 | ||
182 | /* Remainder in (n1n0 - m1m0) >> bm. */ | |
183 | sub_ddmmss (n1, n0, n1, n0, m1, m0); | |
184 | r0 = (n1 << b) | (n0 >> bm); | |
185 | r1 = n1 >> bm; | |
186 | } | |
187 | } | |
188 | } | |
189 | ||
190 | q[0] = q0; q[1] = q1; | |
191 | r[0] = r0, r[1] = r1; | |
192 | } |