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Last change
on this file since 3033 was 1392, checked in by bird, 22 years ago |
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This commit was generated by cvs2svn to compensate for changes in r1391,
which included commits to RCS files with non-trunk default branches.
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Property cvs2svn:cvs-rev
set to
1.1.1.2
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Property svn:eol-style
set to
native
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Property svn:executable
set to
*
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File size:
974 bytes
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| 1 | #include "f2c.h"
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| 2 |
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| 3 | #ifndef LONGBITS
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| 4 | #define LONGBITS 32
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| 5 | #endif
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| 6 |
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| 7 | integer
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| 8 | lbit_bits (integer a, integer b, integer len)
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| 9 | {
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| 10 | /* Assume 2's complement arithmetic */
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| 11 |
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| 12 | unsigned long x, y;
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| 13 |
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| 14 | x = (unsigned long) a;
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| 15 | y = (unsigned long) -1L;
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| 16 | x >>= b;
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| 17 | y <<= len;
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| 18 | return (integer) (x & ~y);
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| 19 | }
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| 20 |
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| 21 | integer
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| 22 | lbit_cshift (integer a, integer b, integer len)
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| 23 | {
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| 24 | unsigned long x, y, z;
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| 25 |
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| 26 | x = (unsigned long) a;
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| 27 | if (len <= 0)
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| 28 | {
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| 29 | if (len == 0)
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| 30 | return 0;
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| 31 | goto full_len;
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| 32 | }
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| 33 | if (len >= LONGBITS)
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| 34 | {
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| 35 | full_len:
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| 36 | if (b >= 0)
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| 37 | {
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| 38 | b %= LONGBITS;
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| 39 | return (integer) (x << b | x >> (LONGBITS - b));
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| 40 | }
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| 41 | b = -b;
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| 42 | b %= LONGBITS;
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| 43 | return (integer) (x << (LONGBITS - b) | x >> b);
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| 44 | }
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| 45 | y = z = (unsigned long) -1;
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| 46 | y <<= len;
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| 47 | z &= ~y;
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| 48 | y &= x;
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| 49 | x &= z;
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| 50 | if (b >= 0)
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| 51 | {
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| 52 | b %= len;
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| 53 | return (integer) (y | (z & (x << b | x >> (len - b))));
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| 54 | }
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| 55 | b = -b;
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| 56 | b %= len;
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| 57 | return (integer) (y | (z & (x >> b | x << (len - b))));
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| 58 | }
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