linux/kernel/time/timeconst.bc
Thomas Gleixner 35728b8209 time: Add SPDX license identifiers
Update the time(r) core files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of the
full boiler plate text.

This work is based on a script and data from Philippe Ombredanne, Kate
Stewart and myself. The data has been created with two independent license
scanners and manual inspection.

The following files do not contain any direct license information and have
been omitted from the big initial SPDX changes:

  timeconst.bc: The .bc files were not touched
  time.c, timer.c, timekeeping.c: Licence was deduced from EXPORT_SYMBOL_GPL

As those files do not contain direct license references they fall under the
project license, i.e. GPL V2 only.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: David Riley <davidriley@chromium.org>
Cc: Colin Cross <ccross@android.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: https://lkml.kernel.org/r/20181031182252.879109557@linutronix.de
2018-11-23 11:51:20 +01:00

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/* SPDX-License-Identifier: GPL-2.0 */
scale=0
define gcd(a,b) {
auto t;
while (b) {
t = b;
b = a % b;
a = t;
}
return a;
}
/* Division by reciprocal multiplication. */
define fmul(b,n,d) {
return (2^b*n+d-1)/d;
}
/* Adjustment factor when a ceiling value is used. Use as:
(imul * n) + (fmulxx * n + fadjxx) >> xx) */
define fadj(b,n,d) {
auto v;
d = d/gcd(n,d);
v = 2^b*(d-1)/d;
return v;
}
/* Compute the appropriate mul/adj values as well as a shift count,
which brings the mul value into the range 2^b-1 <= x < 2^b. Such
a shift value will be correct in the signed integer range and off
by at most one in the upper half of the unsigned range. */
define fmuls(b,n,d) {
auto s, m;
for (s = 0; 1; s++) {
m = fmul(s,n,d);
if (m >= 2^(b-1))
return s;
}
return 0;
}
define timeconst(hz) {
print "/* Automatically generated by kernel/time/timeconst.bc */\n"
print "/* Time conversion constants for HZ == ", hz, " */\n"
print "\n"
print "#ifndef KERNEL_TIMECONST_H\n"
print "#define KERNEL_TIMECONST_H\n\n"
print "#include <linux/param.h>\n"
print "#include <linux/types.h>\n\n"
print "#if HZ != ", hz, "\n"
print "#error \qinclude/generated/timeconst.h has the wrong HZ value!\q\n"
print "#endif\n\n"
if (hz < 2) {
print "#error Totally bogus HZ value!\n"
} else {
s=fmuls(32,1000,hz)
obase=16
print "#define HZ_TO_MSEC_MUL32\tU64_C(0x", fmul(s,1000,hz), ")\n"
print "#define HZ_TO_MSEC_ADJ32\tU64_C(0x", fadj(s,1000,hz), ")\n"
obase=10
print "#define HZ_TO_MSEC_SHR32\t", s, "\n"
s=fmuls(32,hz,1000)
obase=16
print "#define MSEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000), ")\n"
print "#define MSEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000), ")\n"
obase=10
print "#define MSEC_TO_HZ_SHR32\t", s, "\n"
obase=10
cd=gcd(hz,1000)
print "#define HZ_TO_MSEC_NUM\t\t", 1000/cd, "\n"
print "#define HZ_TO_MSEC_DEN\t\t", hz/cd, "\n"
print "#define MSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
print "#define MSEC_TO_HZ_DEN\t\t", 1000/cd, "\n"
print "\n"
s=fmuls(32,1000000,hz)
obase=16
print "#define HZ_TO_USEC_MUL32\tU64_C(0x", fmul(s,1000000,hz), ")\n"
print "#define HZ_TO_USEC_ADJ32\tU64_C(0x", fadj(s,1000000,hz), ")\n"
obase=10
print "#define HZ_TO_USEC_SHR32\t", s, "\n"
s=fmuls(32,hz,1000000)
obase=16
print "#define USEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000000), ")\n"
print "#define USEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000000), ")\n"
obase=10
print "#define USEC_TO_HZ_SHR32\t", s, "\n"
obase=10
cd=gcd(hz,1000000)
print "#define HZ_TO_USEC_NUM\t\t", 1000000/cd, "\n"
print "#define HZ_TO_USEC_DEN\t\t", hz/cd, "\n"
print "#define USEC_TO_HZ_NUM\t\t", hz/cd, "\n"
print "#define USEC_TO_HZ_DEN\t\t", 1000000/cd, "\n"
cd=gcd(hz,1000000000)
print "#define HZ_TO_NSEC_NUM\t\t", 1000000000/cd, "\n"
print "#define HZ_TO_NSEC_DEN\t\t", hz/cd, "\n"
print "#define NSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
print "#define NSEC_TO_HZ_DEN\t\t", 1000000000/cd, "\n"
print "\n"
print "#endif /* KERNEL_TIMECONST_H */\n"
}
halt
}
hz = read();
timeconst(hz)