Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * test_int128.c
4 : * Testbed for roll-our-own 128-bit integer arithmetic.
5 : *
6 : * This is a standalone test program that compares the behavior of an
7 : * implementation in int128.h to an (assumed correct) int128 native type.
8 : *
9 : * Copyright (c) 2017-2025, PostgreSQL Global Development Group
10 : *
11 : *
12 : * IDENTIFICATION
13 : * src/test/modules/test_int128/test_int128.c
14 : *
15 : *-------------------------------------------------------------------------
16 : */
17 :
18 : #include "postgres_fe.h"
19 :
20 : #include <time.h>
21 :
22 : /* Require a native int128 type */
23 : #ifdef HAVE_INT128
24 :
25 : /*
26 : * By default, we test the non-native implementation in int128.h; but
27 : * by predefining USE_NATIVE_INT128 to 1, you can test the native
28 : * implementation, just to be sure.
29 : */
30 : #ifndef USE_NATIVE_INT128
31 : #define USE_NATIVE_INT128 0
32 : #endif
33 :
34 : #include "common/int128.h"
35 : #include "common/pg_prng.h"
36 :
37 : /*
38 : * We assume the parts of this union are laid out compatibly.
39 : */
40 : typedef union
41 : {
42 : int128 i128;
43 : INT128 I128;
44 : struct
45 : {
46 : #ifdef WORDS_BIGENDIAN
47 : int64 hi;
48 : uint64 lo;
49 : #else
50 : uint64 lo;
51 : int64 hi;
52 : #endif
53 : } hl;
54 : } test128;
55 :
56 : #define INT128_HEX_FORMAT "%016" PRIx64 "%016" PRIx64
57 :
58 : /*
59 : * Control version of comparator.
60 : */
61 : static inline int
62 4000000 : my_int128_compare(int128 x, int128 y)
63 : {
64 4000000 : if (x < y)
65 1998672 : return -1;
66 2001328 : if (x > y)
67 2001328 : return 1;
68 0 : return 0;
69 : }
70 :
71 : /*
72 : * Main program.
73 : *
74 : * Generates a lot of random numbers and tests the implementation for each.
75 : * The results should be reproducible, since we use a fixed PRNG seed.
76 : *
77 : * You can give a loop count if you don't like the default 1B iterations.
78 : */
79 : int
80 2 : main(int argc, char **argv)
81 : {
82 : long count;
83 :
84 2 : pg_prng_seed(&pg_global_prng_state, (uint64) time(NULL));
85 :
86 2 : if (argc >= 2)
87 2 : count = strtol(argv[1], NULL, 0);
88 : else
89 0 : count = 1000000000;
90 :
91 2000002 : while (count-- > 0)
92 : {
93 2000000 : int64 x = pg_prng_int64(&pg_global_prng_state);
94 2000000 : int64 y = pg_prng_int64(&pg_global_prng_state);
95 2000000 : int64 z = pg_prng_int64(&pg_global_prng_state);
96 2000000 : int64 w = pg_prng_int64(&pg_global_prng_state);
97 2000000 : int32 z32 = pg_prng_int32(&pg_global_prng_state);
98 : test128 t1;
99 : test128 t2;
100 : test128 t3;
101 : int32 r1;
102 : int32 r2;
103 :
104 : /* prevent division by zero in the 128/32-bit division test */
105 2000000 : while (z32 == 0)
106 0 : z32 = pg_prng_int32(&pg_global_prng_state);
107 :
108 : /* check unsigned addition */
109 2000000 : t1.hl.hi = x;
110 2000000 : t1.hl.lo = y;
111 2000000 : t2 = t1;
112 2000000 : t1.i128 += (int128) (uint64) z;
113 2000000 : int128_add_uint64(&t2.I128, (uint64) z);
114 :
115 2000000 : if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
116 : {
117 0 : printf(INT128_HEX_FORMAT " + unsigned %016" PRIx64 "\n", x, y, z);
118 0 : printf("native = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
119 0 : printf("result = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
120 0 : return 1;
121 : }
122 :
123 : /* check signed addition */
124 2000000 : t1.hl.hi = x;
125 2000000 : t1.hl.lo = y;
126 2000000 : t2 = t1;
127 2000000 : t1.i128 += (int128) z;
128 2000000 : int128_add_int64(&t2.I128, z);
129 :
130 2000000 : if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
131 : {
132 0 : printf(INT128_HEX_FORMAT " + signed %016" PRIx64 "\n", x, y, z);
133 0 : printf("native = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
134 0 : printf("result = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
135 0 : return 1;
136 : }
137 :
138 : /* check 128-bit signed addition */
139 2000000 : t1.hl.hi = x;
140 2000000 : t1.hl.lo = y;
141 2000000 : t2 = t1;
142 2000000 : t3.hl.hi = z;
143 2000000 : t3.hl.lo = w;
144 2000000 : t1.i128 += t3.i128;
145 2000000 : int128_add_int128(&t2.I128, t3.I128);
146 :
147 2000000 : if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
148 : {
149 0 : printf(INT128_HEX_FORMAT " + " INT128_HEX_FORMAT "\n", x, y, z, w);
150 0 : printf("native = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
151 0 : printf("result = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
152 0 : return 1;
153 : }
154 :
155 : /* check unsigned subtraction */
156 2000000 : t1.hl.hi = x;
157 2000000 : t1.hl.lo = y;
158 2000000 : t2 = t1;
159 2000000 : t1.i128 -= (int128) (uint64) z;
160 2000000 : int128_sub_uint64(&t2.I128, (uint64) z);
161 :
162 2000000 : if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
163 : {
164 0 : printf(INT128_HEX_FORMAT " - unsigned %016" PRIx64 "\n", x, y, z);
165 0 : printf("native = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
166 0 : printf("result = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
167 0 : return 1;
168 : }
169 :
170 : /* check signed subtraction */
171 2000000 : t1.hl.hi = x;
172 2000000 : t1.hl.lo = y;
173 2000000 : t2 = t1;
174 2000000 : t1.i128 -= (int128) z;
175 2000000 : int128_sub_int64(&t2.I128, z);
176 :
177 2000000 : if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
178 : {
179 0 : printf(INT128_HEX_FORMAT " - signed %016" PRIx64 "\n", x, y, z);
180 0 : printf("native = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
181 0 : printf("result = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
182 0 : return 1;
183 : }
184 :
185 : /* check 64x64-bit multiply-add */
186 2000000 : t1.hl.hi = x;
187 2000000 : t1.hl.lo = y;
188 2000000 : t2 = t1;
189 2000000 : t1.i128 += (int128) z * (int128) w;
190 2000000 : int128_add_int64_mul_int64(&t2.I128, z, w);
191 :
192 2000000 : if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
193 : {
194 0 : printf(INT128_HEX_FORMAT " + %016" PRIx64 " * %016" PRIx64 "\n", x, y, z, w);
195 0 : printf("native = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
196 0 : printf("result = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
197 0 : return 1;
198 : }
199 :
200 : /* check 64x64-bit multiply-subtract */
201 2000000 : t1.hl.hi = x;
202 2000000 : t1.hl.lo = y;
203 2000000 : t2 = t1;
204 2000000 : t1.i128 -= (int128) z * (int128) w;
205 2000000 : int128_sub_int64_mul_int64(&t2.I128, z, w);
206 :
207 2000000 : if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
208 : {
209 0 : printf(INT128_HEX_FORMAT " - %016" PRIx64 " * %016" PRIx64 "\n", x, y, z, w);
210 0 : printf("native = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
211 0 : printf("result = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
212 0 : return 1;
213 : }
214 :
215 : /* check 128/32-bit division */
216 2000000 : t3.hl.hi = x;
217 2000000 : t3.hl.lo = y;
218 2000000 : t1.i128 = t3.i128 / z32;
219 2000000 : r1 = (int32) (t3.i128 % z32);
220 2000000 : t2 = t3;
221 2000000 : int128_div_mod_int32(&t2.I128, z32, &r2);
222 :
223 2000000 : if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
224 : {
225 0 : printf(INT128_HEX_FORMAT " / signed %08X\n", t3.hl.hi, t3.hl.lo, z32);
226 0 : printf("native = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
227 0 : printf("result = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
228 0 : return 1;
229 : }
230 2000000 : if (r1 != r2)
231 : {
232 0 : printf(INT128_HEX_FORMAT " %% signed %08X\n", t3.hl.hi, t3.hl.lo, z32);
233 0 : printf("native = %08X\n", r1);
234 0 : printf("result = %08X\n", r2);
235 0 : return 1;
236 : }
237 :
238 : /* check comparison */
239 2000000 : t1.hl.hi = x;
240 2000000 : t1.hl.lo = y;
241 2000000 : t2.hl.hi = z;
242 2000000 : t2.hl.lo = w;
243 :
244 4000000 : if (my_int128_compare(t1.i128, t2.i128) !=
245 2000000 : int128_compare(t1.I128, t2.I128))
246 : {
247 0 : printf("comparison failure: %d vs %d\n",
248 : my_int128_compare(t1.i128, t2.i128),
249 : int128_compare(t1.I128, t2.I128));
250 0 : printf("arg1 = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
251 0 : printf("arg2 = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
252 0 : return 1;
253 : }
254 :
255 : /* check case with identical hi parts; above will hardly ever hit it */
256 2000000 : t2.hl.hi = x;
257 :
258 4000000 : if (my_int128_compare(t1.i128, t2.i128) !=
259 2000000 : int128_compare(t1.I128, t2.I128))
260 : {
261 0 : printf("comparison failure: %d vs %d\n",
262 : my_int128_compare(t1.i128, t2.i128),
263 : int128_compare(t1.I128, t2.I128));
264 0 : printf("arg1 = " INT128_HEX_FORMAT "\n", t1.hl.hi, t1.hl.lo);
265 0 : printf("arg2 = " INT128_HEX_FORMAT "\n", t2.hl.hi, t2.hl.lo);
266 0 : return 1;
267 : }
268 : }
269 :
270 2 : return 0;
271 : }
272 :
273 : #else /* ! HAVE_INT128 */
274 :
275 : /*
276 : * For now, do nothing if we don't have a native int128 type.
277 : */
278 : int
279 : main(int argc, char **argv)
280 : {
281 : printf("skipping tests: no native int128 type\n");
282 : return 0;
283 : }
284 :
285 : #endif
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