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Use bitwise test instead of __builtin_popcount

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__builtin_popcount might not be available on all compilers, so using
it requires a configure check and fallback implementation. In fact
on gcc without an -march flag, it gets compiled to a function call to
libgcc. However, we only need to test whether multiple bits are set,
and this can be done easily with a bitwise and.

Signed-off-by: Michael Forney <mforney@mforney.org>
This commit is contained in:
Michael Forney 2019-06-15 14:04:38 -07:00
parent 7160db054a
commit 39c0d633f7
1 changed files with 4 additions and 2 deletions
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6
src/evdev-mt-touchpad.c
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@ -245,10 +245,12 @@ tp_get_touch(struct tp_dispatch *tp, unsigned int slot)
static inline unsigned int
tp_fake_finger_count(struct tp_dispatch *tp)
{
unsigned int fake_touches =
tp->fake_touches & ~(FAKE_FINGER_OVERFLOW|0x1);
/* Only one of BTN_TOOL_DOUBLETAP/TRIPLETAP/... may be set at any
* time */
if (__builtin_popcount(
tp->fake_touches & ~(FAKE_FINGER_OVERFLOW|0x1)) > 1)
if (fake_touches & (fake_touches - 1))
evdev_log_bug_kernel(tp->device,
"Invalid fake finger state %#x\n",
tp->fake_touches);