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author | kargl <kargl@FreeBSD.org> | 2012-10-13 19:53:11 +0000 |
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committer | kargl <kargl@FreeBSD.org> | 2012-10-13 19:53:11 +0000 |
commit | e323b9460e2fa343ab07a6a94df4bfbd183b449e (patch) | |
tree | 3faad3abcd7377655b098dc240bc0a7e25865fca /lib/msun | |
parent | f9c782221359e602e4b46d2d46489ab0ee82311b (diff) | |
download | FreeBSD-src-e323b9460e2fa343ab07a6a94df4bfbd183b449e.zip FreeBSD-src-e323b9460e2fa343ab07a6a94df4bfbd183b449e.tar.gz |
* Update the comment that explains the choice of values in the
table and the requirement on trailing zero bits.
* Remove the __aligned() compiler directives as these were found
to have a negative effect on the produced code.
Submitted by: bde
Approved by: das (mentor)
Diffstat (limited to 'lib/msun')
-rw-r--r-- | lib/msun/ld80/s_expl.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/lib/msun/ld80/s_expl.c b/lib/msun/ld80/s_expl.c index 2395abe..af63668 100644 --- a/lib/msun/ld80/s_expl.c +++ b/lib/msun/ld80/s_expl.c @@ -64,7 +64,7 @@ o_threshold = LD80C(0xb17217f7d1cf79ab, 13, 11356.5234062941439488L), /* log(2**(-16381-64-1)) rounded towards zero: */ u_threshold = LD80C(0xb21dfe7f09e2baa9, 13, -11399.4985314888605581L); -static const double __aligned(64) +static const double /* * ln2/INTERVALS = L1+L2 (hi+lo decomposition for multiplication). L1 must * have at least 22 (= log2(|LDBL_MIN_EXP-extras|) + log2(INTERVALS)) lowest @@ -86,17 +86,18 @@ P6 = 1.3888891738560272e-3; /* 0x16c16c651633ae.0p-62 */ /* * 2^(i/INTERVALS) for i in [0,INTERVALS] is represented by two values where - * the first 53 bits of the significand is stored in hi and the next 53 - * bits are in lo. Tang's paper states that the trailing 6 bits of hi should + * the first 53 bits of the significand are stored in hi and the next 53 + * bits are in lo. Tang's paper states that the trailing 6 bits of hi must * be zero for his algorithm in both single and double precision, because * the table is re-used in the implementation of expm1() where a floating - * point addition involving hi must be exact. The conversion of a 53-bit - * double into a 64-bit long double gives 11 trailing bit, which are zero. + * point addition involving hi must be exact. Here hi is double, so + * converting it to long double gives 11 trailing zero bits. */ static const struct { double hi; double lo; -} s[INTERVALS] __aligned(16) = { +/* XXX should rename 's'. */ +} s[INTERVALS] = { 0x1p+0, 0x0p+0, 0x1.0163da9fb3335p+0, 0x1.b61299ab8cdb7p-54, 0x1.02c9a3e778060p+0, 0x1.dcdef95949ef4p-53, |