msvcrt: Use the acos() implementation from the bundled musl library.

dlls/msvcrt/math.c

@@ -444,79 +444,6 @@ float CDECL tanhf( float x )
 #endif
 
 /*********************************************************************
- *		acos (MSVCRT.@)
- *
- * Copied from musl: src/math/acos.c
- */
-static double acos_R(double z)
-{
-    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 acos( double x )
-{
-    static const double pio2_hi = 1.57079632679489655800e+00,
-                 pio2_lo = 6.12323399573676603587e-17;
-
-    double z, w, s, c, df;
-    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) {
-            /* acos(1)=0, acos(-1)=pi */
-            if (hx >> 31)
-                return 2 * pio2_hi + 7.5231638452626401e-37;
-            return 0;
-        }
-        if (isnan(x)) return x;
-        return math_error(_DOMAIN, "acos", x, 0, 0 / (x - x));
-    }
-    /* |x| < 0.5 */
-    if (ix < 0x3fe00000) {
-        if (ix <= 0x3c600000)  /* |x| < 2**-57 */
-            return pio2_hi + 7.5231638452626401e-37;
-        return pio2_hi - (x - (pio2_lo - x * acos_R(x * x)));
-    }
-    /* x < -0.5 */
-    if (hx >> 31) {
-        z = (1.0 + x) * 0.5;
-        s = sqrt(z);
-        w = acos_R(z) * s - pio2_lo;
-        return 2 * (pio2_hi - (s + w));
-    }
-    /* x > 0.5 */
-    z = (1.0 - x) * 0.5;
-    s = sqrt(z);
-    df = s;
-    llx = (*(ULONGLONG*)&df >> 32) << 32;
-    df = *(double*)&llx;
-    c = (z - df * df) / (s + df);
-    w = acos_R(z) * s + c;
-    return 2 * (df + w);
-}
-
-/*********************************************************************
  *		asin (MSVCRT.@)
  *
  * Copied from musl: src/math/asin.c

libs/musl/src/math/acos.c

@@ -75,7 +75,8 @@ double __cdecl acos(double x)
 				return 2*pio2_hi + 0x1p-120f;
 			return 0;
 		}
-		return 0/(x-x);
+		if (isnan(x)) return x;
+		return math_error(_DOMAIN, "acos", x, 0, 0 / (x - x));
 	}
 	/* |x| < 0.5 */
 	if (ix < 0x3fe00000) {