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Annotation of xinu/sys/ttywrite.c, revision 1.1.1.2

1.1       root        1: /* ttywrite.c - ttywrite, writcopy */
                      2: 
                      3: #include <conf.h>
                      4: #include <kernel.h>
                      5: #include <tty.h>
                      6: #include <io.h>
1.1.1.2 ! root        7: /* set up macros for appropriate SLU as spec. by SLUCHIP:
        !             8:    if SLUCHIP==6850, #include slu6850.h, #define TTYWRITE ttywrite6850, etc.
        !             9:    if SLUCHIP==7201, #include slu7201.h, #define TTYWRITE ttywrite7201, etc.
        !            10:    if SLUCHIP undef.,#include slu.h, #define TTYWRITE ttywrite  (orig. case)
        !            11:    similarly sluaccess.h, other TTY fns */
        !            12: #include <sluinclude.h>
1.1       root       13: 
                     14: /*------------------------------------------------------------------------
                     15:  *  ttywrite - write one or more characters to a tty device
                     16:  *------------------------------------------------------------------------
                     17:  */
1.1.1.2 ! root       18: TTYWRITE(devptr,buff,count)
        !            19:        register struct devsw   *devptr;
        !            20:        register char   *buff;
        !            21:        register int    count;
1.1       root       22: {
1.1.1.2 ! root       23:        register struct csr *cptr;
1.1       root       24:        register struct tty *ttyp;
1.1.1.2 ! root       25:        int avail;
1.1       root       26: 
                     27:        ttyp = &tty[devptr->dvminor];
1.1.1.2 ! root       28:        cptr = (struct csr *)devptr->dvcsr;
        !            29: 
        !            30:        disable();
        !            31:        if ( (avail=scount(ttyp->osem)) > count) {
        !            32:                writcopy(buff, ttyp, count);
        !            33:        } else {
        !            34:                writcopy(buff, ttyp, avail);
        !            35:                buff += avail;
        !            36:                for (count-=avail ; count>0 ; count--)
        !            37:                        TTYPUTC(devptr, *buff++);
        !            38:        }
        !            39:        slutenable(cptr); /* enable transmitter ints */
        !            40:        restore();
1.1       root       41:        return(OK);
                     42: }
                     43: 
                     44: /*------------------------------------------------------------------------
                     45:  *  writcopy - high-speed copy from user's buffer into system buffer
                     46:  *------------------------------------------------------------------------
                     47:  */
                     48: LOCAL writcopy(buff, ttyp, count)
1.1.1.2 ! root       49:        register char   *buff;
        !            50:        register struct tty *ttyp;
        !            51:        register int    count;
1.1       root       52: {
1.1.1.2 ! root       53:        register char   *qhead, *qend, *uend;
1.1       root       54: 
                     55:        qhead = &ttyp->obuff[ttyp->ohead];
                     56:        qend  = &ttyp->obuff[OBUFLEN];
                     57:        uend  = buff + count;
1.1.1.2 ! root       58:        while (buff < uend) {
        !            59:                *qhead++ = *buff++;
1.1       root       60:                if ( qhead >= qend )
                     61:                        qhead = ttyp->obuff;
1.1.1.2 ! root       62:        }
        !            63:        ttyp->ohead = qhead - ttyp->obuff;
        !            64:        sreset(ttyp->osem, scount(ttyp->osem)-count);
1.1       root       65: }

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