Upload

Digital Research

CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v102a/libf/ftoa.c

@@ -0,0 +1,73 @@
+/*
+ *	Ftoa routine with rounding
+ */
+#include <portab.h>
+BYTE	*ftoa(x,str,prec)
+FLOAT	 x;					/* Arg to convert	*/
+BYTE	*str;					/* -> Output area	*/
+WORD	 prec;					/* # digits right of dp */
+{
+REG	WORD	ie,i,k,ndig;			/* Temps		*/
+	BYTE	*savstr;			/* Copy	of str to return*/
+	DOUBLE	y;				/* Temp for rounding	*/
+	
+	savstr = str;				/* Preserve for later	*/
+	ndig = (prec <= 0) ? 1 : ((prec > 22) ? 23 : prec+1);
+	ie = 0;
+	if(x < 0)				/* Fix for negative	*/
+	{
+	  *str++ = '-';
+	   x = -x;				/* Negate		*/
+	}
+/*
+ *	Normalize x to the range 0.0 <= x < 10.0
+ */
+	if(x > 0.0)
+	{
+	  while (x < 1.0)
+	  {
+	     x *= 10.0;
+	     ie--;
+	  }
+	}
+	while(x >= 10.0)
+	{
+	  x /= 10.0;
+	  ie++;
+	}
+	ndig += ie;		/* Adjust digit count for size	*/
+/*
+ *	Now round.
+ */
+	for(y=i=1; i < ndig; i++)
+		y = y / 10.0;		/* Compute round amount	*/
+	x += (y / 2.0);			/* Round by 1/2 lsb	*/
+	if(x >= 10.0) 			/* Did we push it over 10? */
+	{
+	  x = 1.0;
+	  ie++;
+	}
+/*
+ *	Now convert result
+ */
+	if(ie < 0)			/* Leading zeros are special */
+	{
+		*str++ = '0';
+		*str++ = '.';
+		if(ndig < 0) ie = ie -ndig;	/* For underflow */
+		for(i = -1; i > ie; i--)	/* Out the zeros */
+			*str++ = '0';
+	}
+
+	for(i=0; i<ndig; i++)
+	{
+		k = x;				/* Truncate	*/
+		*str++ = k + '0';		/* ASCIIfy	*/
+		if(i == ie)			/* Locate decimal point*/
+			*str++ = '.';
+		x -= (y=k);
+		x *= 10.0;
+	}
+	*str++ = '\0';
+	return(savstr);
+}