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mirror of https://github.com/Mbed-TLS/mbedtls.git synced 2025-08-08 17:42:09 +03:00

Merge pull request #7462 from daverodgman/clz_size_opt

clz size/perf optimisation
This commit is contained in:
Tom Cosgrove
2023-04-26 07:06:30 +01:00
committed by GitHub
4 changed files with 90 additions and 12 deletions

View File

@@ -309,6 +309,36 @@ exit:
}
/* END_CASE */
/* BEGIN_CASE */
void mpi_core_clz(int leading_zeros, int trailing_zeros)
{
if ((size_t) (leading_zeros + trailing_zeros) >= (sizeof(mbedtls_mpi_uint) * 8)) {
// can't fit required number of leading and trailing zeros - skip test
goto exit;
}
// Construct a test input value where the count of leading zeros and
// trailing zeros is given in the test case, and we add ones to fill
// the gap.
mbedtls_mpi_uint x;
if ((leading_zeros + trailing_zeros) > 0) {
// some zero bits
uint32_t s = (sizeof(mbedtls_mpi_uint) * 8 - leading_zeros - trailing_zeros);
x = ((((mbedtls_mpi_uint) 1) << s) - 1) << trailing_zeros;
} else {
// all bits set
x = ~((mbedtls_mpi_uint) 0);
}
size_t n = mbedtls_mpi_core_clz(x);
TEST_EQUAL(n, leading_zeros);
exit:
;
}
/* END_CASE */
/* BEGIN_CASE */
void mpi_core_lt_ct(char *input_X, char *input_Y, int exp_ret)
{

View File

@@ -491,3 +491,35 @@ mpi_core_fill_random:42:0:-1:0:MBEDTLS_ERR_MPI_BAD_INPUT_DATA
Fill random core: 42 bytes, 5 missing limbs
mpi_core_fill_random:42:0:-5:0:MBEDTLS_ERR_MPI_BAD_INPUT_DATA
CLZ: 0 0: all ones
mpi_core_clz:0:0
CLZ: 1 0
mpi_core_clz:1:0
CLZ: 1 1
mpi_core_clz:1:1
CLZ: 4 5
mpi_core_clz:4:5
CLZ: 8 16
mpi_core_clz:8:16
CLZ: 31 0
mpi_core_clz:31:0
CLZ: 32 0
mpi_core_clz:32:0
CLZ: 33 0
mpi_core_clz:33:0
CLZ: 63 0
mpi_core_clz:63:0
CLZ: 64 0
mpi_core_clz:64:0
CLZ: 100000 0: skip overly long input
mpi_core_clz:100000:0