This patch fixes a known bug in bionic libm
due to aliasing issues in gcc 4.2 and 4.4; more
specifically in frexpf.
The function frexpf is used to extract the
mantissa and exponent from a double precision number.
The bug has already been reported here:
https://code.google.com/p/android/issues/detail?id=6697
Change-Id: I2e1f2e0a45906642d2225b9d150ed391d2bf331c
Signed-off-by: Rodrigo Obregon <robregon@ti.com>
Original compiler error:
target arm C: libm <= bionic/libm/src/e_j0f.c
bionic/libm/src/e_j0f.c: In function 'j0f':
bionic/libm/src/e_j0f.c:66: warning: comparison between signed and unsigned integer expressions
bionic/libm/src/e_j0f.c: In function 'y0f':
bionic/libm/src/e_j0f.c:140: warning: comparison between signed and unsigned integer expressions
target arm C: libm <= bionic/libm/src/e_j1.c
It's subtle but ix is masked with 0x7f000000 so it can never ever have a value
greater than 0x80000000. So I switched to using the unmasked hx and added a
cast as a reward to the compiler for being right.
I checked the original routines that e_j0f.c was ported from (in e_j0.c) and
the double's don't use 0x80000000 so this issue didn't exist there.
Let that be a warning to those that just slap on casts to shut up the compiler,
sometimes it's sniffed out a bug for you. :-)
Similar fixes in the other functions.
Change-Id: I7a776e5d4721fc3a9e3bd89179b67e9af3a2ebfa
Warning from compiler:
target arm C: libm <= bionic/libm/src/e_atan2.c
bionic/libm/src/e_atan2.c: In function 'atan2':
bionic/libm/src/e_atan2.c:71: warning: suggest parentheses around arithmetic in operand of '|'
target arm C: libm <= bionic/libm/src/e_atan2f.c
