[liba] add the method ceilf in math library

Change-Id: I339c6e51b5b89d6d18ee5dc55f069919697aea3a

liba/Makefile

@@ -27,6 +27,7 @@ objs += $(addprefix liba/src/external/openbsd/, \
   k_rem_pio2f.o \
   k_sinf.o \
   k_tanf.o \
+  s_ceilf.o \
   s_copysignf.o \
   s_cosf.o \
   s_fabsf.o \

liba/include/math.h

@@ -18,6 +18,7 @@ int isinff(float x);
 int isnanf(float x);
 #define isnan(x) isnanf(x)
 
+float ceilf(float x);
 float copysignf(float x, float y);
 float cosf(float x);
 float fabsf(float x);

liba/src/external/openbsd/s_ceilf.c

@@ -0,0 +1,49 @@
+/* s_ceilf.c -- float version of s_ceil.c.
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.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.
+ * ====================================================
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+static const float huge = 1.0e30;
+
+float
+ceilf(float x)
+{
+	int32_t i0,jj0;
+	u_int32_t i;
+
+	GET_FLOAT_WORD(i0,x);
+	jj0 = ((i0>>23)&0xff)-0x7f;
+	if(jj0<23) {
+	    if(jj0<0) { 	/* raise inexact if x != 0 */
+		if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */
+		    if(i0<0) {i0=0x80000000;} 
+		    else if(i0!=0) { i0=0x3f800000;}
+		}
+	    } else {
+		i = (0x007fffff)>>jj0;
+		if((i0&i)==0) return x; /* x is integral */
+		if(huge+x>(float)0.0) {	/* raise inexact flag */
+		    if(i0>0) i0 += (0x00800000)>>jj0;
+		    i0 &= (~i);
+		}
+	    }
+	} else {
+	    if(jj0==0x80) return x+x;	/* inf or NaN */
+	    else return x;		/* x is integral */
+	}
+	SET_FLOAT_WORD(x,i0);
+	return x;
+}