Sync with upstream FreeBSD libm.
Change-Id: I5585f8b4f2a76041e05e997baf83eb98f2fd8dd0
diff --git a/libm/upstream-freebsd/lib/msun/src/e_acosf.c b/libm/upstream-freebsd/lib/msun/src/e_acosf.c
index 42ba126..ede552e 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_acosf.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_acosf.c
@@ -22,11 +22,17 @@
pio2_hi = 1.5707962513e+00; /* 0x3fc90fda */
static volatile float
pio2_lo = 7.5497894159e-08; /* 0x33a22168 */
+
+/*
+ * The coefficients for the rational approximation were generated over
+ * 0x1p-12f <= x <= 0.5f. The maximum error satisfies log2(e) < -30.084.
+ */
static const float
-pS0 = 1.6666586697e-01,
-pS1 = -4.2743422091e-02,
-pS2 = -8.6563630030e-03,
-qS1 = -7.0662963390e-01;
+pS0 = 1.66666672e-01f, /* 0x3e2aaaab */
+pS1 = -1.19510300e-01f, /* 0xbdf4c1d1 */
+pS2 = 5.47002675e-03f, /* 0x3bb33de9 */
+qS1 = -1.16706085e+00f, /* 0xbf956240 */
+qS2 = 2.90115148e-01f; /* 0x3e9489f9 */
float
acosf(float x)
@@ -46,13 +52,13 @@
if(ix<=0x32800000) return pio2_hi+pio2_lo;/*if|x|<2**-26*/
z = x*x;
p = z*(pS0+z*(pS1+z*pS2));
- q = one+z*qS1;
+ q = one+z*(qS1+z*qS2);
r = p/q;
return pio2_hi - (x - (pio2_lo-x*r));
} else if (hx<0) { /* x < -0.5 */
z = (one+x)*(float)0.5;
p = z*(pS0+z*(pS1+z*pS2));
- q = one+z*qS1;
+ q = one+z*(qS1+z*qS2);
s = sqrtf(z);
r = p/q;
w = r*s-pio2_lo;
@@ -66,7 +72,7 @@
SET_FLOAT_WORD(df,idf&0xfffff000);
c = (z-df*df)/(s+df);
p = z*(pS0+z*(pS1+z*pS2));
- q = one+z*qS1;
+ q = one+z*(qS1+z*qS2);
r = p/q;
w = r*s+c;
return (float)2.0*(df+w);