t_bitops.c revision 1.4
1 /* $NetBSD: t_bitops.c,v 1.4 2011/03/25 04:26:42 jruoho Exp $ */ 2 3 /*- 4 * Copyright (c) 2011 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jukka Ruohonen. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <atf-c.h> 33 34 #include <sys/cdefs.h> 35 #include <sys/bitops.h> 36 37 #include <math.h> 38 39 static const struct { 40 uint32_t val; 41 int ffs; 42 int fls; 43 } bits[] = { 44 45 { 0x00, 0, 0 }, { 0x01, 1, 1 }, { 0x02, 2, 2 }, { 0x03, 1, 2 }, 46 { 0x04, 3, 3 }, { 0x05, 1, 3 }, { 0x06, 2, 3 }, { 0x07, 1, 3 }, 47 { 0x08, 4, 4 }, { 0x09, 1, 4 }, { 0x0A, 2, 4 }, { 0x0B, 1, 4 }, 48 { 0x0C, 3, 4 }, { 0x0D, 1, 4 }, { 0x0E, 2, 4 }, { 0x0F, 1, 4 }, 49 50 { 0x10, 5, 5 }, { 0x11, 1, 5 }, { 0x12, 2, 5 }, { 0x13, 1, 5 }, 51 { 0x14, 3, 5 }, { 0x15, 1, 5 }, { 0x16, 2, 5 }, { 0x17, 1, 5 }, 52 { 0x18, 4, 5 }, { 0x19, 1, 5 }, { 0x1A, 2, 5 }, { 0x1B, 1, 5 }, 53 { 0x1C, 3, 5 }, { 0x1D, 1, 5 }, { 0x1E, 2, 5 }, { 0x1F, 1, 5 }, 54 55 { 0xF0, 5, 8 }, { 0xF1, 1, 8 }, { 0xF2, 2, 8 }, { 0xF3, 1, 8 }, 56 { 0xF4, 3, 8 }, { 0xF5, 1, 8 }, { 0xF6, 2, 8 }, { 0xF7, 1, 8 }, 57 { 0xF8, 4, 8 }, { 0xF9, 1, 8 }, { 0xFA, 2, 8 }, { 0xFB, 1, 8 }, 58 { 0xFC, 3, 8 }, { 0xFD, 1, 8 }, { 0xFE, 2, 8 }, { 0xFF, 1, 8 }, 59 60 }; 61 62 ATF_TC(fast_divide32); 63 ATF_TC_HEAD(fast_divide32, tc) 64 { 65 atf_tc_set_md_var(tc, "descr", "A basic test of fast_divide32(3)"); 66 } 67 68 ATF_TC_BODY(fast_divide32, tc) 69 { 70 uint32_t a, b, q, r, m; 71 uint8_t i, s1, s2; 72 73 a = 0xFFFF; 74 b = 0x000F; 75 76 fast_divide32_prepare(b, &m, &s1, &s2); 77 78 q = fast_divide32(a, b, m, s1, s2); 79 r = fast_remainder32(a, b, m, s1, s2); 80 81 ATF_REQUIRE(q == 0x1111 && r == 0); 82 83 for (i = 1; i < __arraycount(bits); i++) { 84 85 a = bits[i].val; 86 b = bits[i].ffs; 87 88 fast_divide32_prepare(b, &m, &s1, &s2); 89 90 q = fast_divide32(a, b, m, s1, s2); 91 r = fast_remainder32(a, b, m, s1, s2); 92 93 ATF_REQUIRE(q == a / b); 94 ATF_REQUIRE(r == a % b); 95 } 96 } 97 98 ATF_TC(ffsfls); 99 ATF_TC_HEAD(ffsfls, tc) 100 { 101 atf_tc_set_md_var(tc, "descr", "Test ffs32(3)-family for correctness"); 102 } 103 104 ATF_TC_BODY(ffsfls, tc) 105 { 106 uint8_t i; 107 108 ATF_REQUIRE(ffs32(0) == 0x00); 109 ATF_REQUIRE(fls32(0) == 0x00); 110 ATF_REQUIRE(ffs64(0) == 0x00); 111 ATF_REQUIRE(fls64(0) == 0x00); 112 113 ATF_REQUIRE(ffs32(UINT32_MAX) == 0x01); 114 ATF_REQUIRE(fls32(UINT32_MAX) == 0x20); 115 ATF_REQUIRE(ffs64(UINT64_MAX) == 0x01); 116 ATF_REQUIRE(fls64(UINT64_MAX) == 0x40); 117 118 for (i = 1; i < __arraycount(bits); i++) { 119 120 ATF_REQUIRE(ffs32(bits[i].val) == bits[i].ffs); 121 ATF_REQUIRE(fls32(bits[i].val) == bits[i].fls); 122 ATF_REQUIRE(ffs64(bits[i].val) == bits[i].ffs); 123 ATF_REQUIRE(fls64(bits[i].val) == bits[i].fls); 124 125 ATF_REQUIRE(ffs32(bits[i].val << 1) == bits[i].ffs + 1); 126 ATF_REQUIRE(fls32(bits[i].val << 1) == bits[i].fls + 1); 127 ATF_REQUIRE(ffs64(bits[i].val << 1) == bits[i].ffs + 1); 128 ATF_REQUIRE(fls64(bits[i].val << 1) == bits[i].fls + 1); 129 130 ATF_REQUIRE(ffs32(bits[i].val << 9) == bits[i].ffs + 9); 131 ATF_REQUIRE(fls32(bits[i].val << 9) == bits[i].fls + 9); 132 ATF_REQUIRE(ffs64(bits[i].val << 9) == bits[i].ffs + 9); 133 ATF_REQUIRE(fls64(bits[i].val << 9) == bits[i].fls + 9); 134 } 135 } 136 137 ATF_TC(ilog2_1); 138 ATF_TC_HEAD(ilog2_1, tc) 139 { 140 atf_tc_set_md_var(tc, "descr", "Test ilog2(3) for correctness"); 141 } 142 143 ATF_TC_BODY(ilog2_1, tc) 144 { 145 uint64_t i, x; 146 147 for (i = x = 0; i < 64; i++) { 148 149 x = (uint64_t)1 << i; 150 151 ATF_REQUIRE(i == (uint64_t)ilog2(x)); 152 } 153 } 154 155 ATF_TC(ilog2_2); 156 ATF_TC_HEAD(ilog2_2, tc) 157 { 158 /* 159 * This may fail under QEMU; see PR misc/44767. 160 */ 161 atf_tc_set_md_var(tc, "descr", "Test log2(3) vs. ilog2(3)"); 162 } 163 164 ATF_TC_BODY(ilog2_2, tc) 165 { 166 double x, y; 167 uint64_t i; 168 169 for (i = 1; i < UINT32_MAX; i += UINT16_MAX) { 170 171 x = log2(i); 172 y = (double)(ilog2(i)); 173 174 ATF_REQUIRE(ceil(x) >= y); 175 ATF_REQUIRE(fabs(floor(x) - y) < 1.0e-40); 176 } 177 } 178 179 ATF_TP_ADD_TCS(tp) 180 { 181 182 ATF_TP_ADD_TC(tp, fast_divide32); 183 ATF_TP_ADD_TC(tp, ffsfls); 184 ATF_TP_ADD_TC(tp, ilog2_1); 185 ATF_TP_ADD_TC(tp, ilog2_2); 186 187 return atf_no_error(); 188 } 189
Indexes created Sat Oct 11 08:10:02 GMT 2025