BSD 4_3 release

[unix-history] / usr / src / bin / as / asio.c

/*
* Copyright (c) 1982 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#ifndef lint
static char sccsid[] = "@(#)asio.c      5.1 (Berkeley) 4/30/85";
#endif not lint

#include <stdio.h>
#include "as.h"
/*
*      Block I/O routines for logical I/O concurrently in
*      more than one place in the same file.
*/
int     biofd;                  /* file descriptor for block I/O file */
int     biobufsize;             /* optimal block size for I/O */
off_t   boffset;                /* physical position in logical file */
BFILE   *biobufs;               /* the block I/O buffers */

#define error(severity, message) \
       {yyerror(message); if (severity) delexit();}

Flushfield(n)
       register int n;
{
       while (n>0) {
               outb(bitfield);
               bitfield >>= 8;
               n -= 8;
       }
       bitoff=0;
       bitfield=0;
}

/*
*      Block I/O Routines
*/
bopen(bp, off)
       struct biobuf *bp;
       off_t   off;
{

       bp->b_ptr = bp->b_buf = Calloc(1, biobufsize);
       bp->b_nleft = biobufsize - (off % biobufsize);
       bp->b_off = off;
       bp->b_link = biobufs;
       biobufs = bp;
}

int     bwrerror;

bwrite(p, cnt, bp)
       register char *p;
       register int cnt;
       register struct biobuf *bp;
{
       register int put;
       register char *to;

top:
       if (cnt == 0)
               return;
       if (bp->b_nleft) {
               put = bp->b_nleft;
               if (put > cnt)
                       put = cnt;
               bp->b_nleft -= put;
               to = bp->b_ptr;
#ifdef lint
               *to = *to;
#endif lint
               asm("movc3 r8,(r11),(r7)");
               bp->b_ptr += put;
               p += put;
               cnt -= put;
               goto top;
       }
       if (cnt >= biobufsize) {
               if (bp->b_ptr != bp->b_buf)
                       bflush1(bp);
               put = cnt - cnt % biobufsize;
               if (boffset != bp->b_off)
                       (void)lseek(biofd, (long)bp->b_off, 0);
               if (write(biofd, p, put) != put) {
                       bwrerror = 1;
                       error(1, "Output write error");
               }
               bp->b_off += put;
               boffset = bp->b_off;
               p += put;
               cnt -= put;
               goto top;
       }
       bflush1(bp);
       goto top;
}

bflush()
{
       register struct biobuf *bp;

       if (bwrerror)
               return;
       for (bp = biobufs; bp; bp = bp->b_link)
               bflush1(bp);
}

bflush1(bp)
       register struct biobuf *bp;
{
       register int cnt = bp->b_ptr - bp->b_buf;

       if (cnt == 0)
               return;
       if (boffset != bp->b_off)
               (void)lseek(biofd, (long)bp->b_off, 0);
       if (write(biofd, bp->b_buf, cnt) != cnt) {
               bwrerror = 1;
               error(1, "Output write error");
       }
       bp->b_off += cnt;
       boffset = bp->b_off;
       bp->b_ptr = bp->b_buf;
       bp->b_nleft = biobufsize;
}

bflushc(bp, c)
       register struct biobuf *bp;
       char    c;
{
       bflush1(bp);
       bputc(c, bp);
}