timeconst.bc
2.72 KB
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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/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 \qkernel/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"
print "\n"
print "#endif /* KERNEL_TIMECONST_H */\n"
}
halt
}
timeconst(hz)