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qbitbits.c
Go to the documentation of this file.00001 #include "f2c.h"
00002
00003 #ifndef LONGBITS
00004 #define LONGBITS 32
00005 #endif
00006
00007 #ifndef LONG8BITS
00008 #define LONG8BITS (2*LONGBITS)
00009 #endif
00010
00011 integer
00012 #ifdef KR_headers
00013 qbit_bits(a, b, len) longint a; integer b, len;
00014 #else
00015 qbit_bits(longint a, integer b, integer len)
00016 #endif
00017 {
00018
00019
00020 ulongint x, y;
00021
00022 x = (ulongint) a;
00023 y = (ulongint)-1L;
00024 x >>= b;
00025 y <<= len;
00026 return (longint)(x & y);
00027 }
00028
00029 longint
00030 #ifdef KR_headers
00031 qbit_cshift(a, b, len) longint a; integer b, len;
00032 #else
00033 qbit_cshift(longint a, integer b, integer len)
00034 #endif
00035 {
00036 ulongint x, y, z;
00037
00038 x = (ulongint)a;
00039 if (len <= 0) {
00040 if (len == 0)
00041 return 0;
00042 goto full_len;
00043 }
00044 if (len >= LONG8BITS) {
00045 full_len:
00046 if (b >= 0) {
00047 b %= LONG8BITS;
00048 return (longint)(x << b | x >> LONG8BITS - b );
00049 }
00050 b = -b;
00051 b %= LONG8BITS;
00052 return (longint)(x << LONG8BITS - b | x >> b);
00053 }
00054 y = z = (unsigned long)-1;
00055 y <<= len;
00056 z &= ~y;
00057 y &= x;
00058 x &= z;
00059 if (b >= 0) {
00060 b %= len;
00061 return (longint)(y | z & (x << b | x >> len - b));
00062 }
00063 b = -b;
00064 b %= len;
00065 return (longint)(y | z & (x >> b | x << len - b));
00066 }
