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| author | Martin Sandiford <ms@mcdev.com.au> | 2017-08-15 03:08:29 +0200 |
|---|---|---|
| committer | Jack Humbert <jack.humb@gmail.com> | 2017-08-16 01:51:06 +0200 |
| commit | c6224236682c2ac40ccfe752c57fd3ec4905757f (patch) | |
| tree | a688270bccc38e5f9cde1be025fb4e68b6320315 /tmk_core | |
| parent | b7d43ee25371604929ee87dd7bc17430ff0f7a8c (diff) | |
| download | qmk_firmware-c6224236682c2ac40ccfe752c57fd3ec4905757f.tar.gz qmk_firmware-c6224236682c2ac40ccfe752c57fd3ec4905757f.tar.xz | |
Remove floating point calculation in mouse move. Saves approx 650 bytes if no other floating point used.
Diffstat (limited to 'tmk_core')
| -rw-r--r-- | tmk_core/common/mousekey.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/tmk_core/common/mousekey.c b/tmk_core/common/mousekey.c index 23469476e..aa128f0e8 100644 --- a/tmk_core/common/mousekey.c +++ b/tmk_core/common/mousekey.c @@ -55,6 +55,14 @@ uint8_t mk_wheel_time_to_max = MOUSEKEY_WHEEL_TIME_TO_MAX; static uint16_t last_timer = 0; +inline int8_t times_inv_sqrt2(int8_t x) +{ + // 181/256 is pretty close to 1/sqrt(2) + // 0.70703125 0.707106781 + // 1 too small for x=99 and x=198 + // This ends up being a mult and discard lower 8 bits + return (x * 181) >> 8; +} static uint8_t move_unit(void) { @@ -111,10 +119,10 @@ void mousekey_task(void) if (mouse_report.y > 0) mouse_report.y = move_unit(); if (mouse_report.y < 0) mouse_report.y = move_unit() * -1; - /* diagonal move [1/sqrt(2) = 0.7] */ + /* diagonal move [1/sqrt(2)] */ if (mouse_report.x && mouse_report.y) { - mouse_report.x *= 0.7; - mouse_report.y *= 0.7; + mouse_report.x = times_inv_sqrt2(mouse_report.x); + mouse_report.y = times_inv_sqrt2(mouse_report.y); } if (mouse_report.v > 0) mouse_report.v = wheel_unit(); |