[libm] bring over implementations of scalbnf and copysignf

lib/libm/rules.mk

@@ -21,7 +21,9 @@ MODULE_SRCS += \
 	$(LOCAL_DIR)/k_rem_pio2.c \
 	$(LOCAL_DIR)/s_floor.c \
 	$(LOCAL_DIR)/s_scalbn.c \
+	$(LOCAL_DIR)/s_scalbnf.c \
 	$(LOCAL_DIR)/s_copysign.c \
+	$(LOCAL_DIR)/s_copysignf.c \
 	$(LOCAL_DIR)/e_acos.c \
 	$(LOCAL_DIR)/e_acosf.c \
 	$(LOCAL_DIR)/e_asin.c \

lib/libm/s_copysignf.c

@@ -0,0 +1,35 @@
+/* s_copysignf.c -- float version of s_copysign.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 <sys/cdefs.h>
+
+/*
+ * copysignf(float x, float y)
+ * copysignf(x,y) returns a value with the magnitude of x and
+ * with the sign bit of y.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+float
+copysignf(float x, float y)
+{
+        u_int32_t ix,iy;
+        GET_FLOAT_WORD(ix,x);
+        GET_FLOAT_WORD(iy,y);
+        SET_FLOAT_WORD(x,(ix&0x7fffffff)|(iy&0x80000000));
+        return x;
+}

lib/libm/s_scalbnf.c

@@ -0,0 +1,55 @@
+/* s_scalbnf.c -- float version of s_scalbn.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 <sys/cdefs.h>
+
+#include "math.h"
+#include "math_private.h"
+
+static const float
+two25   =  3.355443200e+07,     /* 0x4c000000 */
+twom25  =  2.9802322388e-08,    /* 0x33000000 */
+huge   = 1.0e+30,
+tiny   = 1.0e-30;
+
+float
+scalbnf (float x, int n)
+{
+        int32_t k,ix;
+        GET_FLOAT_WORD(ix,x);
+        k = (ix&0x7f800000)>>23;                /* extract exponent */
+        if (k==0) {                             /* 0 or subnormal x */
+            if ((ix&0x7fffffff)==0) return x; /* +-0 */
+            x *= two25;
+            GET_FLOAT_WORD(ix,x);
+            k = ((ix&0x7f800000)>>23) - 25;
+            if (n< -50000) return tiny*x;       /*underflow*/
+            }
+        if (k==0xff) return x+x;                /* NaN or Inf */
+        k = k+n;
+        if (k >  0xfe) return huge*copysignf(huge,x); /* overflow  */
+        if (k > 0)                              /* normal result */
+            {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
+        if (k <= -25) {
+            if (n > 50000)      /* in case integer overflow in n+k */
+                return huge*copysignf(huge,x);  /*overflow*/
+            else return tiny*copysignf(tiny,x); /*underflow*/
+        }
+        k += 25;                                /* subnormal result */
+        SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
+        return x*twom25;
+}
+
+//__strong_reference(scalbnf, ldexpf);