Index: fusl/src/math/atan2.c |
diff --git a/fusl/src/math/atan2.c b/fusl/src/math/atan2.c |
index 5a1903c6240821b70e6993f3769563c5eb1ba18f..11427d76b482c77f61785c577ab1b1a2716c94e1 100644 |
--- a/fusl/src/math/atan2.c |
+++ b/fusl/src/math/atan2.c |
@@ -39,69 +39,81 @@ |
#include "libm.h" |
-static const double |
-pi = 3.1415926535897931160E+00, /* 0x400921FB, 0x54442D18 */ |
-pi_lo = 1.2246467991473531772E-16; /* 0x3CA1A626, 0x33145C07 */ |
+static const double pi = 3.1415926535897931160E+00, /* 0x400921FB, 0x54442D18 */ |
+ pi_lo = 1.2246467991473531772E-16; /* 0x3CA1A626, 0x33145C07 */ |
-double atan2(double y, double x) |
-{ |
- double z; |
- uint32_t m,lx,ly,ix,iy; |
+double atan2(double y, double x) { |
+ double z; |
+ uint32_t m, lx, ly, ix, iy; |
- if (isnan(x) || isnan(y)) |
- return x+y; |
- EXTRACT_WORDS(ix, lx, x); |
- EXTRACT_WORDS(iy, ly, y); |
- if ((ix-0x3ff00000 | lx) == 0) /* x = 1.0 */ |
- return atan(y); |
- m = ((iy>>31)&1) | ((ix>>30)&2); /* 2*sign(x)+sign(y) */ |
- ix = ix & 0x7fffffff; |
- iy = iy & 0x7fffffff; |
+ if (isnan(x) || isnan(y)) |
+ return x + y; |
+ EXTRACT_WORDS(ix, lx, x); |
+ EXTRACT_WORDS(iy, ly, y); |
+ if ((ix - 0x3ff00000 | lx) == 0) /* x = 1.0 */ |
+ return atan(y); |
+ m = ((iy >> 31) & 1) | ((ix >> 30) & 2); /* 2*sign(x)+sign(y) */ |
+ ix = ix & 0x7fffffff; |
+ iy = iy & 0x7fffffff; |
- /* when y = 0 */ |
- if ((iy|ly) == 0) { |
- switch(m) { |
- case 0: |
- case 1: return y; /* atan(+-0,+anything)=+-0 */ |
- case 2: return pi; /* atan(+0,-anything) = pi */ |
- case 3: return -pi; /* atan(-0,-anything) =-pi */ |
- } |
- } |
- /* when x = 0 */ |
- if ((ix|lx) == 0) |
- return m&1 ? -pi/2 : pi/2; |
- /* when x is INF */ |
- if (ix == 0x7ff00000) { |
- if (iy == 0x7ff00000) { |
- switch(m) { |
- case 0: return pi/4; /* atan(+INF,+INF) */ |
- case 1: return -pi/4; /* atan(-INF,+INF) */ |
- case 2: return 3*pi/4; /* atan(+INF,-INF) */ |
- case 3: return -3*pi/4; /* atan(-INF,-INF) */ |
- } |
- } else { |
- switch(m) { |
- case 0: return 0.0; /* atan(+...,+INF) */ |
- case 1: return -0.0; /* atan(-...,+INF) */ |
- case 2: return pi; /* atan(+...,-INF) */ |
- case 3: return -pi; /* atan(-...,-INF) */ |
- } |
- } |
- } |
- /* |y/x| > 0x1p64 */ |
- if (ix+(64<<20) < iy || iy == 0x7ff00000) |
- return m&1 ? -pi/2 : pi/2; |
+ /* when y = 0 */ |
+ if ((iy | ly) == 0) { |
+ switch (m) { |
+ case 0: |
+ case 1: |
+ return y; /* atan(+-0,+anything)=+-0 */ |
+ case 2: |
+ return pi; /* atan(+0,-anything) = pi */ |
+ case 3: |
+ return -pi; /* atan(-0,-anything) =-pi */ |
+ } |
+ } |
+ /* when x = 0 */ |
+ if ((ix | lx) == 0) |
+ return m & 1 ? -pi / 2 : pi / 2; |
+ /* when x is INF */ |
+ if (ix == 0x7ff00000) { |
+ if (iy == 0x7ff00000) { |
+ switch (m) { |
+ case 0: |
+ return pi / 4; /* atan(+INF,+INF) */ |
+ case 1: |
+ return -pi / 4; /* atan(-INF,+INF) */ |
+ case 2: |
+ return 3 * pi / 4; /* atan(+INF,-INF) */ |
+ case 3: |
+ return -3 * pi / 4; /* atan(-INF,-INF) */ |
+ } |
+ } else { |
+ switch (m) { |
+ case 0: |
+ return 0.0; /* atan(+...,+INF) */ |
+ case 1: |
+ return -0.0; /* atan(-...,+INF) */ |
+ case 2: |
+ return pi; /* atan(+...,-INF) */ |
+ case 3: |
+ return -pi; /* atan(-...,-INF) */ |
+ } |
+ } |
+ } |
+ /* |y/x| > 0x1p64 */ |
+ if (ix + (64 << 20) < iy || iy == 0x7ff00000) |
+ return m & 1 ? -pi / 2 : pi / 2; |
- /* z = atan(|y/x|) without spurious underflow */ |
- if ((m&2) && iy+(64<<20) < ix) /* |y/x| < 0x1p-64, x<0 */ |
- z = 0; |
- else |
- z = atan(fabs(y/x)); |
- switch (m) { |
- case 0: return z; /* atan(+,+) */ |
- case 1: return -z; /* atan(-,+) */ |
- case 2: return pi - (z-pi_lo); /* atan(+,-) */ |
- default: /* case 3 */ |
- return (z-pi_lo) - pi; /* atan(-,-) */ |
- } |
+ /* z = atan(|y/x|) without spurious underflow */ |
+ if ((m & 2) && iy + (64 << 20) < ix) /* |y/x| < 0x1p-64, x<0 */ |
+ z = 0; |
+ else |
+ z = atan(fabs(y / x)); |
+ switch (m) { |
+ case 0: |
+ return z; /* atan(+,+) */ |
+ case 1: |
+ return -z; /* atan(-,+) */ |
+ case 2: |
+ return pi - (z - pi_lo); /* atan(+,-) */ |
+ default: /* case 3 */ |
+ return (z - pi_lo) - pi; /* atan(-,-) */ |
+ } |
} |