lbitbits.c File Reference

#include "f2c.h"

Include dependency graph for lbitbits.c:

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Defines
#define	LONGBITS   32
Functions
integer	lbit_bits (integer a, integer b, integer len)
integer	lbit_cshift (integer a, integer b, integer len)

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Define Documentation

#define LONGBITS   32

Definition at line 7 of file lbitbits.c.

Referenced by lbit_cshift().

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Function Documentation

integer lbit_bits	(	integer	a,
		integer	b,
		integer	len
	)

Definition at line 14 of file lbitbits.c.

References L, long, x, and y.

{
        /* Assume 2's complement arithmetic */

        unsigned long x, y;

        x = (unsigned long) a;
        y = (unsigned long)-1L;
        x >>= b;
        y <<= len;
        return (integer)(x & ~y);
        }

integer lbit_cshift	(	integer	a,
		integer	b,
		integer	len
	)

Definition at line 32 of file lbitbits.c.

References long, LONGBITS, x, y, and z.

{
        unsigned long x, y, z;

        x = (unsigned long)a;
        if (len <= 0) {
                if (len == 0)
                        return 0;
                goto full_len;
                }
        if (len >= LONGBITS) {
 full_len:
                if (b >= 0) {
                        b %= LONGBITS;
                        return (integer)(x << b | x >> (LONGBITS -b) );
                        }
                b = -b;
                b %= LONGBITS;
                return (integer)(x << (LONGBITS - b) | x >> b);
                }
        y = z = (unsigned long)-1;
        y <<= len;
        z &= ~y;
        y &= x;
        x &= z;
        if (b >= 0) {
                b %= len;
                return (integer)(y | z & (x << b | x >> (len - b)));
                }
        b = -b;
        b %= len;
        return (integer)(y | z & (x >> b | x << (len - b)));
        }

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