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| author | Michael Brown | 2018-03-20 19:42:39 +0100 |
|---|---|---|
| committer | Michael Brown | 2018-03-20 19:56:01 +0100 |
| commit | 0d35411f88dd37dda755d52b4549337f8299c698 (patch) | |
| tree | 9129fb0cee236f97af83024b5910cb2cb2b83b08 /src/crypto | |
| parent | [golan] Set log_max_qp to 1 (diff) | |
| download | ipxe-0d35411f88dd37dda755d52b4549337f8299c698.tar.gz ipxe-0d35411f88dd37dda755d52b4549337f8299c698.tar.xz ipxe-0d35411f88dd37dda755d52b4549337f8299c698.zip | |
[rng] Use fixed-point calculations for min-entropy quantities
We currently perform various min-entropy calculations using build-time
floating-point arithmetic. No floating-point code ends up in the
final binary, since the results are eventually converted to integers
and asserted to be compile-time constants.
Though this mechanism is undoubtedly cute, it inhibits us from using
"-mno-sse" to prevent the use of SSE registers by the compiler.
Fix by using fixed-point arithmetic instead.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/crypto')
| -rw-r--r-- | src/crypto/entropy.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/crypto/entropy.c b/src/crypto/entropy.c index 5acbc025..ced6fd92 100644 --- a/src/crypto/entropy.c +++ b/src/crypto/entropy.c @@ -70,7 +70,8 @@ repetition_count_cutoff ( void ) { * where W is set at 2^(-30) (in ANS X9.82 Part 2 (October * 2011 Draft) Section 8.5.2.1.3.1). */ - max_repetitions = ( 1 + ( 30 / min_entropy_per_sample() ) ); + max_repetitions = ( 1 + ( MIN_ENTROPY ( 30 ) / + min_entropy_per_sample() ) ); /* Round up to a whole number of repetitions. We don't have * the ceil() function available, so do the rounding by hand. @@ -237,7 +238,7 @@ adaptive_proportion_cutoff ( void ) { /* Look up cutoff value in cutoff table */ n = ADAPTIVE_PROPORTION_WINDOW_SIZE; - h = min_entropy_per_sample(); + h = ( min_entropy_per_sample() / MIN_ENTROPY_SCALE ); cutoff = adaptive_proportion_cutoff_lookup ( n, h ); /* Fail unless cutoff value is a build-time constant */ |