- Implemented fmin()/fminf(), fmax()/fmaxf(), fdim()/fdimf() for C99.

- Ported acosf(), asinf(), atan2f(), atanf(), ceilf(), expf(), floorf(),
  fmodf(), frexpf(), ldexpf(), log10f(), logbf(), logf(), modff(), powf(), sqrtf(),
  scalbn() and scalbnf() for C99.

- Ported cbrt(), cbrtf(), erf(), erff(), erfc(), erfcf(), expm1(),
  expm1f(), ilogb(), ilogbf(), log1p() and log1pf() for C99.


git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@14963 87f5fb63-7c3d-0410-a384-fd976d0f7a62

library/math_log10f.c

@@ -1,5 +1,5 @@
 /*
- * $Id: math_log10f.c,v 1.1 2005-05-29 11:19:01 obarthel Exp $
+ * $Id: math_log10f.c,v 1.2 2005-05-29 14:45:32 obarthel Exp $
  *
  * :ts=4
  *
@@ -29,6 +29,18 @@
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * PowerPC math library based in part on work by Sun Microsystems
+ * 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.
+ *
+ *
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
  */
 
 #ifndef _MATH_HEADERS_H
@@ -41,11 +53,38 @@
 
 /****************************************************************************/
 
+static const float
+two25      =  3.3554432000e+07, /* 0x4c000000 */
+ivln10     =  4.3429449201e-01, /* 0x3ede5bd9 */
+log10_2hi  =  3.0102920532e-01, /* 0x3e9a2080 */
+log10_2lo  =  7.9034151668e-07; /* 0x355427db */
+
+static const float zero   =  0.0;
+
 float
 log10f(float x)
 {
-	/* ZZZ unimplemented */
-	return(0);
+	float y,z;
+	LONG i,k,hx;
+
+	GET_FLOAT_WORD(hx,x);
+
+        k=0;
+        if (hx < 0x00800000) {                  /* x < 2**-126  */
+            if ((hx&0x7fffffff)==0)
+                return -two25/zero;             /* log(+-0)=-inf */
+            if (hx<0) return (x-x)/zero;        /* log(-#) = NaN */
+            k -= 25; x *= two25; /* subnormal number, scale up x */
+	    GET_FLOAT_WORD(hx,x);
+        }
+	if (hx >= 0x7f800000) return x+x;
+	k += (hx>>23)-127;
+	i  = ((ULONG)k&0x80000000U)>>31;
+        hx = (hx&0x007fffff)|((0x7f-i)<<23);
+        y  = (float)(k+i);
+	SET_FLOAT_WORD(x,hx);
+	z  = y*log10_2lo + ivln10*logf(x);
+	return  z+y*log10_2hi;
 }
 
 /****************************************************************************/