diff --git a/liba/Makefile b/liba/Makefile
index e3659c1a2..676fa88d0 100644
--- a/liba/Makefile
+++ b/liba/Makefile
@@ -57,6 +57,7 @@ liba_src += $(addprefix liba/src/external/openbsd/, \
   s_copysignf.c \
   s_cosf.c \
   s_erf.c \
+  s_erff.c \
   s_expm1f.o\
   s_fabsf.c \
   s_fmaxf.c \
diff --git a/liba/src/external/openbsd/s_erff.c b/liba/src/external/openbsd/s_erff.c
new file mode 100644
index 000000000..d2d6b7b5d
--- /dev/null
+++ b/liba/src/external/openbsd/s_erff.c
@@ -0,0 +1,185 @@
+/* s_erff.c -- float version of s_erf.c.
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ * Taken from openlibm at 5b0e7e981321687ac0abe711fdeb30adcd9da932 and
+ * modified for Numworks Epsilon by Neven Sajko <nsajko@gmail.com>
+ */
+
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+//__FBSDID("$FreeBSD: src/lib/msun/src/s_erff.c,v 1.8 2008/02/22 02:30:35 das Exp $");
+
+#include "math.h"
+
+#include "math_private.h"
+
+static const float
+tiny	    = 1e-30,
+half=  5.0000000000e-01, /* 0x3F000000 */
+one =  1.0000000000e+00, /* 0x3F800000 */
+two =  2.0000000000e+00, /* 0x40000000 */
+/*
+ * Coefficients for approximation to erf on [0,0.84375]
+ */
+efx =  1.2837916613e-01, /* 0x3e0375d4 */
+efx8=  1.0270333290e+00, /* 0x3f8375d4 */
+/*
+ *  Domain [0, 0.84375], range ~[-5.4446e-10,5.5197e-10]:
+ *  |(erf(x) - x)/x - p(x)/q(x)| < 2**-31.
+ */
+pp0  =  1.28379166e-01F, /*  0x1.06eba8p-3 */
+pp1  = -3.36030394e-01F, /* -0x1.58185ap-2 */
+pp2  = -1.86260219e-03F, /* -0x1.e8451ep-10 */
+qq1  =  3.12324286e-01F, /*  0x1.3fd1f0p-2 */
+qq2  =  2.16070302e-02F, /*  0x1.620274p-6 */
+qq3  = -1.98859419e-03F, /* -0x1.04a626p-9 */
+/*
+ * Domain [0.84375, 1.25], range ~[-1.953e-11,1.940e-11]:
+ * |(erf(x) - erx) - p(x)/q(x)| < 2**-36.
+ */
+erx  =  8.42697144e-01F, /*  0x1.af7600p-1.  erf(1) rounded to 16 bits. */
+pa0  =  3.64939137e-06F, /*  0x1.e9d022p-19 */
+pa1  =  4.15109694e-01F, /*  0x1.a91284p-2 */
+pa2  = -1.65179938e-01F, /* -0x1.5249dcp-3 */
+pa3  =  1.10914491e-01F, /*  0x1.c64e46p-4 */
+qa1  =  6.02074385e-01F, /*  0x1.344318p-1 */
+qa2  =  5.35934687e-01F, /*  0x1.126608p-1 */
+qa3  =  1.68576106e-01F, /*  0x1.593e6ep-3 */
+qa4  =  5.62181212e-02F, /*  0x1.cc89f2p-5 */
+/*
+ * Domain [1.25,1/0.35], range ~[-7.043e-10,7.457e-10]:
+ * |log(x*erfc(x)) + x**2 + 0.5625 - r(x)/s(x)| < 2**-30
+ */
+ra0  = -9.87132732e-03F, /* -0x1.4376b2p-7 */
+ra1  = -5.53605914e-01F, /* -0x1.1b723cp-1 */
+ra2  = -2.17589188e+00F, /* -0x1.1683a0p+1 */
+ra3  = -1.43268085e+00F, /* -0x1.6ec42cp+0 */
+sa1  =  5.45995426e+00F, /*  0x1.5d6fe4p+2 */
+sa2  =  6.69798088e+00F, /*  0x1.acabb8p+2 */
+sa3  =  1.43113089e+00F, /*  0x1.6e5e98p+0 */
+sa4  = -5.77397496e-02F, /* -0x1.d90108p-5 */
+/*
+ * Domain [1/0.35, 11], range ~[-2.264e-13,2.336e-13]:
+ * |log(x*erfc(x)) + x**2 + 0.5625 - r(x)/s(x)| < 2**-42
+ */
+rb0  = -9.86494310e-03F, /* -0x1.434124p-7 */
+rb1  = -6.25171244e-01F, /* -0x1.401672p-1 */
+rb2  = -6.16498327e+00F, /* -0x1.8a8f16p+2 */
+rb3  = -1.66696873e+01F, /* -0x1.0ab70ap+4 */
+rb4  = -9.53764343e+00F, /* -0x1.313460p+3 */
+sb1  =  1.26884899e+01F, /*  0x1.96081cp+3 */
+sb2  =  4.51839523e+01F, /*  0x1.6978bcp+5 */
+sb3  =  4.72810211e+01F, /*  0x1.7a3f88p+5 */
+sb4  =  8.93033314e+00F; /*  0x1.1dc54ap+3 */
+
+
+float
+erff(float x)
+{
+	int32_t hx,ix,i;
+	float R,S,P,Q,s,y,z,r;
+	GET_FLOAT_WORD(hx,x);
+	ix = hx&0x7fffffff;
+	if(ix>=0x7f800000) {		/* erf(nan)=nan */
+	    i = ((u_int32_t)hx>>31)<<1;
+	    return (float)(1-i)+one/x;	/* erf(+-inf)=+-1 */
+	}
+
+	if(ix < 0x3f580000) {		/* |x|<0.84375 */
+            if(ix < 0x38800000) {       /* |x|<2**-14 */
+                if (ix < 0x04000000)    /* |x|<0x1p-119 */
+                    return (8*x+efx8*x)/8;      /* avoid spurious underflow */
+		return x + efx*x;
+	    }
+	    z = x*x;
+            r = pp0+z*(pp1+z*pp2);
+            s = one+z*(qq1+z*(qq2+z*qq3));
+	    y = r/s;
+	    return x + x*y;
+	}
+	if(ix < 0x3fa00000) {		/* 0.84375 <= |x| < 1.25 */
+	    s = fabsf(x)-one;
+            P = pa0+s*(pa1+s*(pa2+s*pa3));
+            Q = one+s*(qa1+s*(qa2+s*(qa3+s*qa4)));
+	    if(hx>=0) return erx + P/Q; else return -erx - P/Q;
+	}
+	if (ix >= 0x40800000) {		/* inf>|x|>=4 */
+	    if(hx>=0) return one-tiny; else return tiny-one;
+	}
+	x = fabsf(x);
+ 	s = one/(x*x);
+	if(ix< 0x4036DB6E) {	/* |x| < 1/0.35 */
+            R=ra0+s*(ra1+s*(ra2+s*ra3));
+            S=one+s*(sa1+s*(sa2+s*(sa3+s*sa4)));
+	} else {	/* |x| >= 1/0.35 */
+            R=rb0+s*(rb1+s*(rb2+s*(rb3+s*rb4)));
+            S=one+s*(sb1+s*(sb2+s*(sb3+s*sb4)));
+        }
+        SET_FLOAT_WORD(z,hx&0xffffe000);
+        r  = expf(-z*z-0.5625F)*expf((z-x)*(z+x)+R/S);
+	if(hx>=0) return one-r/x; else return  r/x-one;
+}
+
+float
+erfcf(float x)
+{
+	int32_t hx,ix;
+	float R,S,P,Q,s,y,z,r;
+	GET_FLOAT_WORD(hx,x);
+	ix = hx&0x7fffffff;
+	if(ix>=0x7f800000) {			/* erfc(nan)=nan */
+						/* erfc(+-inf)=0,2 */
+	    return (float)(((u_int32_t)hx>>31)<<1)+one/x;
+	}
+
+	if(ix < 0x3f580000) {		/* |x|<0.84375 */
+	    if(ix < 0x33800000)  	/* |x|<2**-56 */
+		return one-x;
+	    z = x*x;
+            r = pp0+z*(pp1+z*pp2);
+            s = one+z*(qq1+z*(qq2+z*qq3));
+	    y = r/s;
+	    if(hx < 0x3e800000) {  	/* x<1/4 */
+		return one-(x+x*y);
+	    } else {
+		r = x*y;
+		r += (x-half);
+	        return half - r ;
+	    }
+	}
+	if(ix < 0x3fa00000) {		/* 0.84375 <= |x| < 1.25 */
+	    s = fabsf(x)-one;
+            P = pa0+s*(pa1+s*(pa2+s*pa3));
+            Q = one+s*(qa1+s*(qa2+s*(qa3+s*qa4)));
+	    if(hx>=0) {
+	        z  = one-erx; return z - P/Q;
+	    } else {
+		z = erx+P/Q; return one+z;
+	    }
+	}
+	if (ix < 0x41300000) {		/* |x|<28 */
+	    x = fabsf(x);
+ 	    s = one/(x*x);
+	    if(ix< 0x4036DB6D) {	/* |x| < 1/.35 ~ 2.857143*/
+                R=ra0+s*(ra1+s*(ra2+s*ra3));
+                S=one+s*(sa1+s*(sa2+s*(sa3+s*sa4)));
+	    } else {			/* |x| >= 1/.35 ~ 2.857143 */
+                if(hx<0&&ix>=0x40a00000) return two-tiny;/* x < -5 */
+                R=rb0+s*(rb1+s*(rb2+s*(rb3+s*rb4)));
+                S=one+s*(sb1+s*(sb2+s*(sb3+s*sb4)));
+	    }
+            SET_FLOAT_WORD(z,hx&0xffffe000);
+            r  = expf(-z*z-0.5625F)*expf((z-x)*(z+x)+R/S);
+	    if(hx>0) return r/x; else return two-r/x;
+	} else {
+	    if(hx>0) return tiny*tiny; else return two-tiny;
+	}
+}
diff --git a/libaxx/include/cmath b/libaxx/include/cmath
index 5bcfbfa7b..9fdad6b7a 100644
--- a/libaxx/include/cmath
+++ b/libaxx/include/cmath
@@ -114,6 +114,8 @@ inline constexpr float ceil(float x) { return __builtin_ceilf(x); }
 inline constexpr float copysign(float x, float y) { return __builtin_copysignf(x, y); }
 inline constexpr float cos(float x) { return __builtin_cosf(x); }
 inline constexpr float cosh(float x) { return __builtin_coshf(x); }
+inline constexpr float erf(float x) { return __builtin_erff(x); }
+inline constexpr float erfc(float x) { return __builtin_erfcf(x); }
 inline constexpr float exp(float x) { return __builtin_expf(x); }
 inline constexpr float expm1(float x) { return __builtin_expm1f(x); }
 inline constexpr float fabs(float x) { return __builtin_fabsf(x); }