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Diffstat (limited to 'src/base/math/atan2.c')
-rw-r--r-- | src/base/math/atan2.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/base/math/atan2.c b/src/base/math/atan2.c new file mode 100644 index 0000000..a681a80 --- /dev/null +++ b/src/base/math/atan2.c @@ -0,0 +1,24 @@ +#include <u.h> +#include <base.h> +/* + atan2 discovers what quadrant the angle + is in and calls atan. +*/ + +double +math·atan2(double arg1, double arg2) +{ + + if(arg1+arg2 == arg1) { + if(arg1 >= 0) + return math·PIO2; + return -math·PIO2; + } + arg1 = math·atan(arg1/arg2); + if(arg2 < 0) { + if(arg1 <= 0) + return arg1 + math·PI; + return arg1 - math·PI; + } + return arg1; +} |