first usable version of kernel and commands

After an year of hard work, this is a first "usable" version of Jehanne.

qa/lib/c/sqrt.c

@@ -0,0 +1,83 @@
+/*
+ * This file is part of the UCB release of Plan 9. It is subject to the license
+ * terms in the LICENSE file found in the top-level directory of this
+ * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
+ * part of the UCB release of Plan 9, including this file, may be copied,
+ * modified, propagated, or distributed except according to the terms contained
+ * in the LICENSE file.
+ */
+
+#include <u.h>
+#include <libc.h>
+
+/*
+	sqrtC returns the square root of its floating
+	point argument. Newton's method.
+
+	calls frexp
+*/
+double
+sqrtC(double arg)
+{
+	double x, temp;
+	int exp, i;
+
+	if(arg <= 0) {
+		if(arg < 0)
+			return NaN();
+		return 0;
+	}
+	if(isInf(arg, 1))
+		return arg;
+	x = frexp(arg, &exp);
+	while(x < 0.5) {
+		x *= 2;
+		exp--;
+	}
+	/*
+	 * NOTE
+	 * this wont work on 1's comp
+	 */
+	if(exp & 1) {
+		x *= 2;
+		exp--;
+	}
+	temp = 0.5 * (1.0+x);
+
+	while(exp > 60) {
+		temp *= (1L<<30);
+		exp -= 60;
+	}
+	while(exp < -60) {
+		temp /= (1L<<30);
+		exp += 60;
+	}
+	if(exp >= 0)
+		temp *= 1L << (exp/2);
+	else
+		temp /= 1L << (-exp/2);
+	for(i=0; i<=4; i++)
+		temp = 0.5*(temp + arg/temp);
+	return temp;
+}
+
+void
+main(void)
+{
+	double v;
+	char *a, *b;
+	
+	for(v = 4; v < 65536; v += v + 1) {
+		a = smprint("%f", sqrtC(v));
+		b = smprint("%f", sqrt(v));
+		if(strcmp(a, b)){
+			print("FAIL\n");
+			exits("FAIL");
+		}
+		free(a);
+		free(b);
+	}
+	
+	print("PASS\n");
+	exits("PASS");
+}