bread.c

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/* 
 * bread.c - 
 * 
 * Author:  Todd W. Fuqua
 *      Computer Science Dept.
 *      University of Utah
 * Date:    Wed Jul 25 1984
 * Copyright (c) 1984 Todd W. Fuqua
 * 
 * $Header: bread.c,v 2.3 86/06/18 11:46:19 thomas Exp $
 * $Log:    bread.c,v $
 * Revision 2.3  86/06/18  11:46:19  thomas
 * Add vax ifdef.
 * 
 * Revision 2.2  85/04/26  15:03:56  thomas
 * Lint and potential bug fixes.
 * 
 * Revision 2.1  85/03/05  16:00:22  thomas
 * *** empty log message ***
 * 
 */
static char rcs_ident[] = "$Header: bread.c,v 2.3 86/06/18 11:46:19 thomas Exp $";


#include "stdio.h"
bread(ptr, size, iop)
unsigned size;
register char *ptr;
register FILE *iop;
{
    register unsigned ndone, s;
    register int c;

    if (!size) return 0;

    ndone = size;
    if ( iop->_cnt >= ndone )
    {
        switch ( ndone )
        {
        /* WARNING -- the first two cases should be
         * "sizeof(short)" and "sizeof(long)", but the compiler
         * doesn't like those.
         */
        case sizeof(short): *(short *)ptr = *(short *)iop->_ptr;
                break;
        case sizeof(long):  *(long *)ptr = *(int *)iop->_ptr;
                break;
        default:        /*bcopy( iop->_ptr, ptr, ndone );*/
#ifdef vax
                asm("   movl  4(r10),r0");
                asm("   movc3 r9,(r0),(r11)");
#else
                bcopy( iop->_ptr, ptr, ndone );
#endif
        }
        iop->_cnt -= ndone;
        iop->_ptr += ndone;
    }
    else
        while ( ndone != 0 )
        {
        if ( iop->_cnt == 0 )
            if ((c = _filbuf(iop)) == EOF)
            return (size - ndone) ;
            else
            {
            *ptr++ = c;
            ndone--;
            }

        if (s = ndone)
        {
            if ( s > iop->_cnt )
            s = iop->_cnt;
            iop->_cnt -= s; /* work-around for CC bug */
/*          bcopy( iop->_ptr, ptr, s );*/
            asm("   movl  4(r10),r0");
            asm("   movc3 r8,(r0),(r11)");
            iop->_ptr += s;
            ndone -= s;
            ptr += s;
        }
        }

    return size;
}