Initial revision

mach/proto/fp/cif4.c

@@ -0,0 +1,56 @@
+/*
+	CONVERT INTEGER TO FLOAT
+
+	THIS ROUTINE WORKS BY FILLING AN EXTENDED
+	WITH THE INTEGER VALUE IN EXTENDED FORMAT
+	AND USES COMPACT() TO PUT IT INTO THE PROPER
+	FLOATING POINT PRECISION.
+*/
+
+#include "FP_types.h"
+
+_float
+cif4(ss,src)
+int	ss;	/* source size */
+long	src;	/* largest possible integer to convert */
+{
+	EXTEND	buf;
+	short	*ipt;
+	long	i_src;
+	_float	*result;
+
+	zrf_ext(&buf);
+	if (ss == sizeof(long))	{
+		buf.exp = 33;
+		i_src = src;
+		result = (_float *) &src;
+	}
+	else	{
+		ipt = (short *) &src;
+		i_src = (long) *ipt;
+		buf.exp = 17;
+		result = (_float *) &ss;
+	}
+#ifdef	PRT_STDERR
+	fprintf(stderr,"CIF4(ds(%d),ss(%d),src(%D))\n\n",4,ss,i_src);
+#endif
+	if (i_src == 0)	{
+		*result = (_float) 0L;
+		return(0L);
+	}
+			/* ESTABLISHED THAT src != 0	*/
+			/* adjust exponent field	*/
+	buf.sign = (i_src < 0) ? 0x8000 : 0;
+			/* clear sign bit of integer	*/
+			/* move to mantissa field	*/
+	buf.m1 = (i_src < 0) ? -i_src : i_src;
+			/* adjust mantissa field	*/
+	if (ss != sizeof(long))
+		buf.m1 <<= 16;
+	nrm_ext(&buf);		/* adjust mantissa field	*/
+#ifdef	PRT_STDERR
+	fprintf(stderr,"CIF() buf.exp after nrm_ext() == %d\n\n",buf.exp);
+#endif
+	compact(&buf,(_double *) result,4);	/* put on stack */
+	return(*result);
+}