Piotr Caban : msvcrt: Import asin from musl.
Alexandre Julliard
julliard at winehq.org
Thu Aug 6 16:33:46 CDT 2020
Module: wine
Branch: master
Commit: 2cb6a1780c37ad8f3a261600c3b187a192486b22
URL: https://source.winehq.org/git/wine.git/?a=commit;h=2cb6a1780c37ad8f3a261600c3b187a192486b22
Author: Piotr Caban <piotr at codeweavers.com>
Date: Thu Aug 6 16:59:17 2020 +0200
msvcrt: Import asin from musl.
Signed-off-by: Piotr Caban <piotr at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>
---
dlls/msvcrt/math.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 66 insertions(+), 4 deletions(-)
diff --git a/dlls/msvcrt/math.c b/dlls/msvcrt/math.c
index daa94c6f7c..723c341c65 100644
--- a/dlls/msvcrt/math.c
+++ b/dlls/msvcrt/math.c
@@ -654,13 +654,75 @@ double CDECL MSVCRT_acos( double x )
/*********************************************************************
* MSVCRT_asin (MSVCRT.@)
+ *
+ * Copied from musl: src/math/asin.c
*/
+static double asin_R(double z)
+{
+ /* coefficients for R(x^2) */
+ static const double pS0 = 1.66666666666666657415e-01,
+ pS1 = -3.25565818622400915405e-01,
+ pS2 = 2.01212532134862925881e-01,
+ pS3 = -4.00555345006794114027e-02,
+ pS4 = 7.91534994289814532176e-04,
+ pS5 = 3.47933107596021167570e-05,
+ qS1 = -2.40339491173441421878e+00,
+ qS2 = 2.02094576023350569471e+00,
+ qS3 = -6.88283971605453293030e-01,
+ qS4 = 7.70381505559019352791e-02;
+
+ double p, q;
+ p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * pS5)))));
+ q = 1.0 + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
+ return p / q;
+}
+
double CDECL MSVCRT_asin( double x )
{
- double ret = atan2(x, sqrt((1 - x) * (1 + x)));
- if (x < -1.0 || x > 1.0 || !isfinite(x))
- return math_error(_DOMAIN, "asin", x, 0, ret);
- return ret;
+ static const double pio2_hi = 1.57079632679489655800e+00,
+ pio2_lo = 6.12323399573676603587e-17;
+
+ double z, r, s;
+ unsigned int hx, ix;
+ ULONGLONG llx;
+
+ hx = *(ULONGLONG*)&x >> 32;
+ ix = hx & 0x7fffffff;
+ /* |x| >= 1 or nan */
+ if (ix >= 0x3ff00000) {
+ unsigned int lx;
+ lx = *(ULONGLONG*)&x;
+ if (((ix - 0x3ff00000) | lx) == 0)
+ /* asin(1) = +-pi/2 with inexact */
+ return x * pio2_hi + 7.5231638452626401e-37;
+ if (isnan(x)) return x;
+ return math_error(_DOMAIN, "asin", x, 0, 0 / (x - x));
+ }
+ /* |x| < 0.5 */
+ if (ix < 0x3fe00000) {
+ /* if 0x1p-1022 <= |x| < 0x1p-26, avoid raising underflow */
+ if (ix < 0x3e500000 && ix >= 0x00100000)
+ return x;
+ return x + x * asin_R(x * x);
+ }
+ /* 1 > |x| >= 0.5 */
+ z = (1 - fabs(x)) * 0.5;
+ s = sqrt(z);
+ r = asin_R(z);
+ if (ix >= 0x3fef3333) { /* if |x| > 0.975 */
+ x = pio2_hi - (2 * (s + s * r) - pio2_lo);
+ } else {
+ double f, c;
+ /* f+c = sqrt(z) */
+ f = s;
+ llx = (*(ULONGLONG*)&f >> 32) << 32;
+ f = *(double*)&llx;
+ c = (z - f * f) / (s + f);
+ x = 0.5 * pio2_hi - (2 * s * r - (pio2_lo - 2 * c) - (0.5 * pio2_hi - 2 * f));
+ }
+ if (hx >> 31)
+ return -x;
+ return x;
}
/*********************************************************************
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