From: Anatoly Burakov Date: Thu, 20 Dec 2018 12:09:49 +0000 (+0000) Subject: eal: add 64-bit fls function X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=43c9e6c205ab491779c67bba5be3ff8c3f45998e;p=dpdk.git eal: add 64-bit fls function Add missing implementation for 64-bit fls function, and extend unit test to test the new function as well. Signed-off-by: Anatoly Burakov --- diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h index d102f2cecb..7b50b84795 100644 --- a/lib/librte_eal/common/include/rte_common.h +++ b/lib/librte_eal/common/include/rte_common.h @@ -547,6 +547,24 @@ rte_bsf64_safe(uint64_t v, uint32_t *pos) return 1; } +/** + * Return the last (most-significant) bit set. + * + * @note The last (most significant) bit is at position 64. + * @note rte_fls_u64(0) = 0, rte_fls_u64(1) = 1, + * rte_fls_u64(0x8000000000000000) = 64 + * + * @param x + * The input parameter. + * @return + * The last (most-significant) bit set, or 0 if the input is 0. + */ +static inline int +rte_fls_u64(uint64_t x) +{ + return (x == 0) ? 0 : 64 - __builtin_clzll(x); +} + #ifndef offsetof /** Return the offset of a field in a structure. */ #define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER) diff --git a/test/test/test_common.c b/test/test/test_common.c index 4a42aaed8f..f6dd4c18d8 100644 --- a/test/test/test_common.c +++ b/test/test/test_common.c @@ -242,6 +242,8 @@ test_fls(void) }; for (i = 0; i < RTE_DIM(test); i++) { + uint64_t arg64; + arg = test[i].arg; rc = rte_fls_u32(arg); expected = test[i].rc; @@ -250,6 +252,25 @@ test_fls(void) arg, rc, expected); return TEST_FAILED; } + /* 64-bit version */ + arg = test[i].arg; + rc = rte_fls_u64(arg); + expected = test[i].rc; + if (rc != expected) { + printf("Wrong rte_fls_u64(0x%x) rc=%d, expected=%d\n", + arg, rc, expected); + return TEST_FAILED; + } + /* 64-bit version shifted by 32 bits */ + arg64 = (uint64_t)test[i].arg << 32; + rc = rte_fls_u64(arg64); + /* don't shift zero */ + expected = test[i].rc == 0 ? 0 : test[i].rc + 32; + if (rc != expected) { + printf("Wrong rte_fls_u64(0x%" PRIx64 ") rc=%d, expected=%d\n", + arg64, rc, expected); + return TEST_FAILED; + } } return 0;