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Annotation of researchv10no/sys/io/drbit.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  *  DR-11C interface
                      3:  *  The routines in this driver are not called through the normal
                      4:  *  device interface.  Instead, they are available for other device
                      5:  *  drivers to use to send arbitrary information out on a DR-11C.
                      6:  */
                      7: 
                      8: #include "sys/param.h"
                      9: #include "sys/ubaddr.h"
                     10: 
                     11: /* number of output bits available in a DR -- must be a power of 2 */
                     12: #define DRWIDTH 16
                     13: 
                     14: /* DRWIDTH is 2**DRSHIFT */
                     15: #define DRSHIFT 4
                     16: 
                     17: extern int drcnt;
                     18: extern struct ubaddr draddr[];
                     19: extern caddr_t drreg[];
                     20: 
                     21: struct drreg {
                     22:        u_short drcsr, drout, drin;
                     23: };
                     24: 
                     25: /* set bit n of the dr-11 complex to v */
                     26: drsetbit (n, v)
                     27:        register int n;
                     28:        register int v;
                     29: {
                     30:        register struct drreg *drptr;
                     31:        register int i;
                     32: 
                     33:        i = n>>DRSHIFT;
                     34:        if (i < 0 || i >= drcnt)
                     35:                return;
                     36:        if ((drptr = (struct drreg *)drreg[i]) == NULL) {
                     37:                if ((drptr = (struct drreg *)ubaddr(&draddr[i])) == NULL
                     38:                ||   ubbadaddr(draddr[i].ubno, &drptr->drout, sizeof(short))) {
                     39:                        printf("drbit dr11 %d absent\n", i);
                     40:                        return;
                     41:                }
                     42:                drreg[i] = (caddr_t)drptr;
                     43:        }
                     44:        i = 1 << (n & (DRWIDTH - 1));
                     45:        if (v)
                     46:                drptr->drout |= i;
                     47:        else
                     48:                drptr->drout &= ~i;
                     49: }

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