shithub: wl3d

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unfuck nanosec()

--- a/nanosec.c

+++ b/nanosec.c

@@ -2,6 +2,10 @@

 #include <libc.h>

 #include <tos.h>

+enum {

+	Nsec = 1000000000ULL,

+};

+

 /*

  * nsec() is wallclock and can be adjusted by timesync

  * so need to use cycles() instead, but fall back to

@@ -11,7 +15,7 @@

 nanosec(void)

 {

 	static u64int fasthz, xstart;

-	u64int x, div;

+	u64int x;

 	if(fasthz == ~0ULL)

 		return nsec() - xstart;

@@ -29,8 +33,8 @@

 	cycles(&x);

 	x -= xstart;

-	/* this is ugly */

-	for(div = 1000000000ULL; x < 0x1999999999999999ULL && div > 1 ; div /= 10ULL, x *= 10ULL);

+	u64int q = x / fasthz;

+	u64int r = x % fasthz;

-	return x / (fasthz / div);

+	return q*Nsec + r*Nsec/fasthz;

 }