Commit Graph

6 Commits

Author SHA1 Message Date
Petro Karashchenko
b859f2750b libc/math: fix log and logf calculations on ARMv7 (and maybe others)
Probably this is a bug of a GCC, but on AMRv7 the code "if (relax_factor > 1)"
generates "bne.n" instruction if "relax_factor" is "int". Few lines above
"relax_factor *= LOG_RELAX_MULTIPLIER;" is done without overflow check hence
at some moment overflow occurs and "relax_factor" becomes a zero and condition
"if (relax_factor > 1)" becomes always evaluated to "true" hence "epsilon"
becomes zero always.

Probably this is not the best way to fix the bug (The best way is to report it
to GCC), but this change allows to get correct behavior of "log" and "logf" for
ARMv7 based MCUs

Signed-off-by: Petro Karashchenko <petro.karashchenko@gmail.com>
2022-01-01 20:38:38 +08:00
SPRESENSE
2e80d5e38e libs/libc/math: Fix calculation error of log function
Fix a problem where the log function would loop infinitely by
calculation error when a specific value was passed. For example,
in the following case, the log function loops infinitely and
never returns. So, this commit fixes to return the right value.

  double a = 7883961.5;
  double b = log(a);
2021-07-10 12:28:34 -07:00
Gregory Nutt
7769bd490c sched/signal/sig_nanosleep.c: Fix an error introduced with recent commit. Noted by Jussi Kivilinna. 2018-09-17 06:21:25 -06:00
Rajan Gill
d647127d14 libs/libc/math: Small change to log() and logf() that improves accuracy and convergence time 2018-09-16 15:14:15 -06:00
Rajan Gill
6da2658fdd libs/libc/math: Add variable convergence in log() and logf() to avoid hangs caused by failure to converge for very specific input values. 2018-09-16 12:22:36 -06:00
Gregory Nutt
cf99fb40c9 This commit moves all of the libraries under a common directory called libs/. This most certainly break libcxx and uClibc++ for now.
Squashed commit of the following:

    libs/libxx:  Fix some confusing in naming.  If the directory is called libxx, then the library must be libxx.a (unless perhaps LIBCXX is selected).
    libs/:  Fix paths in moved library directories.
    libs:  Brute force move of libc, libnx, and libxx to libs.  Cannot yet build it in that configuration.
2018-05-29 13:21:26 -06:00