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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
commit46651ce6fe013220ed397add242004d764fc0153 (patch)
tree6e5299f990f88e60174a1d3ae6e48eedd2688b2b /src/tools/testint128.c
parentInitial commit. (diff)
downloadpostgresql-14-46651ce6fe013220ed397add242004d764fc0153.tar.xz
postgresql-14-46651ce6fe013220ed397add242004d764fc0153.zip
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/tools/testint128.c')
-rw-r--r--src/tools/testint128.c183
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+/*-------------------------------------------------------------------------
+ *
+ * testint128.c
+ * Testbed for roll-our-own 128-bit integer arithmetic.
+ *
+ * This is a standalone test program that compares the behavior of an
+ * implementation in int128.h to an (assumed correct) int128 native type.
+ *
+ * Copyright (c) 2017-2021, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ * src/tools/testint128.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+
+/*
+ * By default, we test the non-native implementation in int128.h; but
+ * by predefining USE_NATIVE_INT128 to 1, you can test the native
+ * implementation, just to be sure.
+ */
+#ifndef USE_NATIVE_INT128
+#define USE_NATIVE_INT128 0
+#endif
+
+#include "common/int128.h"
+
+/*
+ * We assume the parts of this union are laid out compatibly.
+ */
+typedef union
+{
+ int128 i128;
+ INT128 I128;
+ union
+ {
+#ifdef WORDS_BIGENDIAN
+ int64 hi;
+ uint64 lo;
+#else
+ uint64 lo;
+ int64 hi;
+#endif
+ } hl;
+} test128;
+
+
+/*
+ * Control version of comparator.
+ */
+static inline int
+my_int128_compare(int128 x, int128 y)
+{
+ if (x < y)
+ return -1;
+ if (x > y)
+ return 1;
+ return 0;
+}
+
+/*
+ * Get a random uint64 value.
+ * We don't assume random() is good for more than 16 bits.
+ */
+static uint64
+get_random_uint64(void)
+{
+ uint64 x;
+
+ x = (uint64) (random() & 0xFFFF) << 48;
+ x |= (uint64) (random() & 0xFFFF) << 32;
+ x |= (uint64) (random() & 0xFFFF) << 16;
+ x |= (uint64) (random() & 0xFFFF);
+ return x;
+}
+
+/*
+ * Main program.
+ *
+ * Generates a lot of random numbers and tests the implementation for each.
+ * The results should be reproducible, since we don't call srandom().
+ *
+ * You can give a loop count if you don't like the default 1B iterations.
+ */
+int
+main(int argc, char **argv)
+{
+ long count;
+
+ if (argc >= 2)
+ count = strtol(argv[1], NULL, 0);
+ else
+ count = 1000000000;
+
+ while (count-- > 0)
+ {
+ int64 x = get_random_uint64();
+ int64 y = get_random_uint64();
+ int64 z = get_random_uint64();
+ test128 t1;
+ test128 t2;
+
+ /* check unsigned addition */
+ t1.hl.hi = x;
+ t1.hl.lo = y;
+ t2 = t1;
+ t1.i128 += (int128) (uint64) z;
+ int128_add_uint64(&t2.I128, (uint64) z);
+
+ if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
+ {
+ printf("%016lX%016lX + unsigned %lX\n", x, y, z);
+ printf("native = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("result = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+
+ /* check signed addition */
+ t1.hl.hi = x;
+ t1.hl.lo = y;
+ t2 = t1;
+ t1.i128 += (int128) z;
+ int128_add_int64(&t2.I128, z);
+
+ if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
+ {
+ printf("%016lX%016lX + signed %lX\n", x, y, z);
+ printf("native = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("result = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+
+ /* check multiplication */
+ t1.i128 = (int128) x * (int128) y;
+
+ t2.hl.hi = t2.hl.lo = 0;
+ int128_add_int64_mul_int64(&t2.I128, x, y);
+
+ if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
+ {
+ printf("%lX * %lX\n", x, y);
+ printf("native = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("result = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+
+ /* check comparison */
+ t1.hl.hi = x;
+ t1.hl.lo = y;
+ t2.hl.hi = z;
+ t2.hl.lo = get_random_uint64();
+
+ if (my_int128_compare(t1.i128, t2.i128) !=
+ int128_compare(t1.I128, t2.I128))
+ {
+ printf("comparison failure: %d vs %d\n",
+ my_int128_compare(t1.i128, t2.i128),
+ int128_compare(t1.I128, t2.I128));
+ printf("arg1 = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("arg2 = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+
+ /* check case with identical hi parts; above will hardly ever hit it */
+ t2.hl.hi = x;
+
+ if (my_int128_compare(t1.i128, t2.i128) !=
+ int128_compare(t1.I128, t2.I128))
+ {
+ printf("comparison failure: %d vs %d\n",
+ my_int128_compare(t1.i128, t2.i128),
+ int128_compare(t1.I128, t2.I128));
+ printf("arg1 = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("arg2 = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+ }
+
+ return 0;
+}