kernel: Replace timeconst.pl with a bc script

[cascardo/linux.git] / kernel / timeconst.bc

diff --git a/kernel/timeconst.bc b/kernel/timeconst.bc
new file mode 100644 (file)
index 0000000..511bdf2
--- /dev/null
+++ b/kernel/timeconst.bc
@@ -0,0 +1,108 @@
+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)