ref: b597cdf52dfe14c9835a9543b46e34356384e3c9
parent: 3db49bf5553d1e91a66dd43e37b6a77957600ca5
author: qwx <qwx@sciops.net>
date: Sat Mar 15 09:16:34 EDT 2025
add nanosec; mk: fix rule for external files
--- a/fns.h
+++ b/fns.h
@@ -7,3 +7,4 @@
void redraw(void);
void initimg(void);
void quit(void);
+u64int nanosec(void);
--- a/mkfile
+++ b/mkfile
@@ -1,13 +1,15 @@
</$objtype/mkfile
BIN=$home/bin/$objtype
TARG=gm4s
+HFILES= dat.h fns.h /sys/src/games/eui.h
OFILES=\
game.$O\
gm4s.$O\
+ nanosec.$O\
piece.$O\
- eui.$O\
+ /sys/src/games/eui.$O\
-HFILES= dat.h fns.h
</sys/src/cmd/mkone
-eui.$O: /sys/src/games/eui.c
- $CC $CFLAGS $prereq
+
+%.$O: %.c
+ $CC $CFLAGS -o $target $stem.c
--- /dev/null
+++ b/nanosec.c
@@ -1,0 +1,40 @@
+#include <u.h>
+#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
+ * nsec() in case we can't
+ */
+u64int
+nanosec(void)
+{+ static u64int fasthz, xstart;
+ u64int x;
+
+ if(fasthz == ~0ULL)
+ return nsec() - xstart;
+
+ if(fasthz == 0){+ if(_tos->cyclefreq){+ fasthz = _tos->cyclefreq;
+ cycles(&xstart);
+ } else {+ fasthz = ~0ULL;
+ xstart = nsec();
+ }
+ return 0;
+ }
+ cycles(&x);
+ x -= xstart;
+
+ u64int q = x / fasthz;
+ u64int r = x % fasthz;
+
+ return q*Nsec + r*Nsec/fasthz;
+}