1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 scale=0
4
5 define gcd(a,b) {
6 auto t;
7 while (b) {
8 t = b;
9 b = a % b;
10 a = t;
11 }
12 return a;
13 }
14
15 /* Division by reciprocal multiplication. */
16 define fmul(b,n,d) {
17 return (2^b*n+d-1)/d;
18 }
19
20 /* Adjustment factor when a ceiling value is used. Use as:
21 (imul * n) + (fmulxx * n + fadjxx) >> xx) */
22 define fadj(b,n,d) {
23 auto v;
24 d = d/gcd(n,d);
25 v = 2^b*(d-1)/d;
26 return v;
27 }
28
29 /* Compute the appropriate mul/adj values as well as a shift count,
30 which brings the mul value into the range 2^b-1 <= x < 2^b. Such
31 a shift value will be correct in the signed integer range and off
32 by at most one in the upper half of the unsigned range. */
33 define fmuls(b,n,d) {
34 auto s, m;
35 for (s = 0; 1; s++) {
36 m = fmul(s,n,d);
37 if (m >= 2^(b-1))
38 return s;
39 }
40 return 0;
41 }
42
43 define timeconst(hz) {
44 print "/* Automatically generated by kernel/time/timeconst.bc */\n"
45 print "/* Time conversion constants for HZ == ", hz, " */\n"
46 print "\n"
47
48 print "#ifndef KERNEL_TIMECONST_H\n"
49 print "#define KERNEL_TIMECONST_H\n\n"
50
51 print "#include <linux/param.h>\n"
52 print "#include <linux/types.h>\n\n"
53
54 print "#if HZ != ", hz, "\n"
55 print "#error \qinclude/generated/timeconst.h has the wrong HZ value!\q\n"
56 print "#endif\n\n"
57
58 if (hz < 2) {
59 print "#error Totally bogus HZ value!\n"
60 } else {
61 s=fmuls(32,1000,hz)
62 obase=16
63 print "#define HZ_TO_MSEC_MUL32\tU64_C(0x", fmul(s,1000,hz), ")\n"
64 print "#define HZ_TO_MSEC_ADJ32\tU64_C(0x", fadj(s,1000,hz), ")\n"
65 obase=10
66 print "#define HZ_TO_MSEC_SHR32\t", s, "\n"
67
68 s=fmuls(32,hz,1000)
69 obase=16
70 print "#define MSEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000), ")\n"
71 print "#define MSEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000), ")\n"
72 obase=10
73 print "#define MSEC_TO_HZ_SHR32\t", s, "\n"
74
75 obase=10
76 cd=gcd(hz,1000)
77 print "#define HZ_TO_MSEC_NUM\t\t", 1000/cd, "\n"
78 print "#define HZ_TO_MSEC_DEN\t\t", hz/cd, "\n"
79 print "#define MSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
80 print "#define MSEC_TO_HZ_DEN\t\t", 1000/cd, "\n"
81 print "\n"
82
83 s=fmuls(32,1000000,hz)
84 obase=16
85 print "#define HZ_TO_USEC_MUL32\tU64_C(0x", fmul(s,1000000,hz), ")\n"
86 print "#define HZ_TO_USEC_ADJ32\tU64_C(0x", fadj(s,1000000,hz), ")\n"
87 obase=10
88 print "#define HZ_TO_USEC_SHR32\t", s, "\n"
89
90 s=fmuls(32,hz,1000000)
91 obase=16
92 print "#define USEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000000), ")\n"
93 print "#define USEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000000), ")\n"
94 obase=10
95 print "#define USEC_TO_HZ_SHR32\t", s, "\n"
96
97 obase=10
98 cd=gcd(hz,1000000)
99 print "#define HZ_TO_USEC_NUM\t\t", 1000000/cd, "\n"
100 print "#define HZ_TO_USEC_DEN\t\t", hz/cd, "\n"
101 print "#define USEC_TO_HZ_NUM\t\t", hz/cd, "\n"
102 print "#define USEC_TO_HZ_DEN\t\t", 1000000/cd, "\n"
103
104 cd=gcd(hz,1000000000)
105 print "#define HZ_TO_NSEC_NUM\t\t", 1000000000/cd, "\n"
106 print "#define HZ_TO_NSEC_DEN\t\t", hz/cd, "\n"
107 print "#define NSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
108 print "#define NSEC_TO_HZ_DEN\t\t", 1000000000/cd, "\n"
109 print "\n"
110
111 print "#endif /* KERNEL_TIMECONST_H */\n"
112 }
113 halt
114 }
115
116 hz = read();
117 timeconst(hz)
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