Upload

Digital Research

CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v101/c/libe/etoa.c

@@ -0,0 +1,81 @@
+/*
+	Copyright 1982
+	Alcyon Corporation
+	8716 Production Ave.
+	San Diego, Ca.  92121
+*/
+
+/*char *version "@(#) etoa - jan 24, 1982"; */
+
+/*
+ *	IEEE Floating Point to Ascii String Conversion Routine :
+ *		IEEE Standard Single Precision Representation Floating Point
+ *
+ *	char *
+ *	etoa(f,buf,prec)
+ *	float f;
+ *	char *buf;
+ *	int prec;
+ *
+ *	No more than 9 decimal digits are allowed in single precision.
+ *	Largest positive number is 3.4 * 10^33 and the smallest positive
+ *	number is 1.2 * 10^-38.
+ *	Rely's on the fact that a long and a float are both 32 bits.
+ */
+
+#define BIAS	127L
+
+float _ieeetof();
+
+char *
+etoa(fl,buf,prec)
+long fl;	/* ieee formatted float */
+char *buf;
+int prec;
+{
+	register char *bp;
+	register int exp, digit;
+	float f;
+
+	prec = (prec <= 0) ? 1 : (prec <= 9) ? prec : 9;
+	bp = buf;
+	f = _ieeetof(fl);	/* get floating point value */
+	if (f < 0.0) {		/* negative float */
+		*bp++ = '-';
+		f = -f;		/* make it positive */
+	}
+	if (f == 0.0) {
+		*bp++ = '0';	*bp++ = '.';
+		while (prec--)
+			*bp++ = '0';
+		*bp++ = 'e';	*bp++ = '0';	*bp++ = '0';	*bp = 0;
+		return(buf);
+	}
+	for (exp=0; f < 1.0; f = f * 10.0)	/* get negative exp */
+		exp--;
+	for ( ; f >= 1.0; f = f / 10.0)		/* 0.XXXXXXE00 * 10^exp */
+		exp++;
+
+	exp--;	/* for one explicit digit */
+	f = f * 10.0;
+	digit = f;	/* get one digit */
+	f = f - digit;
+	*bp++ = digit + '0';
+	*bp++ = '.';
+	while(prec-- > 0) {	/* get prec. decimal places */
+		f = f * 10.0;
+		digit = f;
+		f = f - digit;
+		*bp++ = digit + '0';
+	}
+	*bp++ = 'e';
+	if (exp < 0) {
+		exp = -exp;
+		*bp++ = '-';
+	}
+	*bp++ = (exp / 10) + '0';
+	*bp++ = (exp % 10) + '0';
+	*bp = 0;
+	return(buf);
+}
+