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Annotation of coherent/f/usr/include.78/sys/fun.h, revision 1.1.1.1

1.1       root        1: /* (-lgl
                      2:  *     COHERENT 386 Device Driver Kit release 2.0
                      3:  *     Copyright (c) 1982, 1992 by Mark Williams Company.
                      4:  *     All rights reserved. May not be copied without permission.
                      5:  -lgl) */
                      6: /*
                      7:  * Coherent.  Some useful functions.
                      8:  */
                      9: 
                     10: #ifndef        __SYS_FUN_H__
                     11: #define        __SYS_FUN_H__
                     12: 
                     13: /*
                     14:  * Number of elements in a structure.
                     15:  */
                     16: #define nel(a)         (sizeof(a)/sizeof((a)[0]))
                     17: 
                     18: /*
                     19:  * Character pointer to integer.
                     20:  */
                     21: #define cpi(p)         ((char *)(p) - (char *)0)
                     22: 
                     23: /*
                     24:  * Round a number upwards to be a multiple of another.
                     25:  */
                     26: #define        roundu(n1, n2)  (((n1)+(n2)-1)/n2*n2)
                     27: 
                     28: /*
                     29:  * Offset in bytes of `m' in the structure `s'.
                     30:  */
                     31: #define offset(s, m)   ((int) &(((struct s *) 0)->m))
                     32: 
                     33: /*
                     34:  * Add an unsigned number without overflow.
                     35:  */
                     36: #define        addu(v, n) {                                                    \
                     37:        unsigned x;                                                     \
                     38:                                                                        \
                     39:        x = v + (n);                                                    \
                     40:        v = x>=v ? x : MAXU;                                            \
                     41: }
                     42: 
                     43: /*
                     44:  * Subtract an unsigned number without overflow.
                     45:  */
                     46: #define        subu(v, n) {                                                    \
                     47:        unsigned x;                                                     \
                     48:                                                                        \
                     49:        x = v - (n);                                                    \
                     50:        v = x<=v ? x : 0;                                               \
                     51: };
                     52: 
                     53: #endif

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