UNIX 6th Ed. - /usr/sys/dmr/tc.c

   1: #
   2: /*
   3:  */
   4: 
   5: /*
   6:  * TC-11 DECtape driver
   7:  */
   8: 
   9: #include "../param.h"
  10: #include "../conf.h"
  11: #include "../buf.h"
  12: #include "../user.h"
  13: 
  14: struct {
  15:     int tccsr;
  16:     int tccm;
  17:     int tcwc;
  18:     int tcba;
  19:     int tcdt;
  20: };
  21: 
  22: struct  devtab  tctab;
  23: char    tcper[8];
  24: 
  25: #define TCADDR  0177340
  26: #define NTCBLK  578
  27: 
  28: #define TAPERR  0100000
  29: #define TREV    04000
  30: #define READY   0200
  31: #define IENABLE 0100
  32: #define UPS 0200
  33: #define ENDZ    0100000
  34: #define BLKM    02000
  35: #define ILGOP   010000
  36: #define SELERR  04000
  37: 
  38: #define SAT 0
  39: #define RNUM    02
  40: #define RDATA   04
  41: #define SST 010
  42: #define WDATA   014
  43: #define GO  01
  44: 
  45: #define SFORW   1
  46: #define SREV    2
  47: #define SIO 3
  48: 
  49: tcclose(dev)
  50: {
  51:     bflush(dev);
  52:     tcper[dev&07] = 0;
  53: }
  54: 
  55: tcstrategy(abp)
  56: struct buf *abp;
  57: {
  58:     register struct buf *bp;
  59: 
  60:     bp = abp;
  61:     if(bp->b_flags&B_PHYS)
  62:         mapalloc(bp);
  63:     if(bp->b_blkno >= NTCBLK || tcper[bp->b_dev&07]) {
  64:         bp->b_flags =| B_ERROR;
  65:         iodone(bp);
  66:         return;
  67:     }
  68:     bp->av_forw = 0;
  69:     spl6();
  70:     if (tctab.d_actf==0)
  71:         tctab.d_actf = bp;
  72:     else
  73:         tctab.d_actl->av_forw = bp;
  74:     tctab.d_actl = bp;
  75:     if (tctab.d_active==0)
  76:         tcstart();
  77:     spl0();
  78: }
  79: 
  80: tcstart()
  81: {
  82:     register struct buf *bp;
  83:     register int *tccmp, com;
  84: 
  85: loop:
  86:     tccmp = &TCADDR->tccm;
  87:     if ((bp = tctab.d_actf) == 0)
  88:         return;
  89:     if(tcper[bp->b_dev&07]) {
  90:         if((tctab.d_actf = bp->av_forw) == 0)
  91:             (*tccmp).lobyte = SAT|GO;
  92:         bp->b_flags =| B_ERROR;
  93:         iodone(bp);
  94:         goto loop;
  95:     }
  96:     if (((*tccmp).hibyte&07) != bp->b_dev.d_minor)
  97:         (*tccmp).lobyte = SAT|GO;
  98:     tctab.d_errcnt = 20;
  99:     tctab.d_active = SFORW;
 100:     com = (bp->b_dev.d_minor<<8) | IENABLE|RNUM|GO;
 101:     if ((TCADDR->tccsr & UPS) == 0) {
 102:         com =| TREV;
 103:         tctab.d_active = SREV;
 104:     }
 105:     *tccmp = com;
 106: }
 107: 
 108: tcintr()
 109: {
 110:     register struct buf *bp;
 111:     register int *tccmp;
 112:     register int *tcdtp;
 113: 
 114:     tccmp = &TCADDR->tccm;
 115:     tcdtp = &TCADDR->tccsr;
 116:     bp = tctab.d_actf;
 117:     if (*tccmp&TAPERR) {
 118:         if((*tcdtp&(ENDZ|BLKM)) == 0)
 119:             deverror(bp, *tcdtp, 0);
 120:         if(*tcdtp & (ILGOP|SELERR)) {
 121:             tcper[bp->b_dev&07]++;
 122:             tctab.d_errcnt = 0;
 123:         }
 124:         *tccmp =& ~TAPERR;
 125:         if (--tctab.d_errcnt  <= 0) {
 126:             bp->b_flags =| B_ERROR;
 127:             goto done;
 128:         }
 129:         if (*tccmp&TREV) {
 130:         setforw:
 131:             tctab.d_active = SFORW;
 132:             *tccmp =& ~TREV;
 133:         } else {
 134:         setback:
 135:             tctab.d_active = SREV;
 136:             *tccmp =| TREV;
 137:         }
 138:         (*tccmp).lobyte = IENABLE|RNUM|GO;
 139:         return;
 140:     }
 141:     tcdtp = &TCADDR->tcdt;
 142:     switch (tctab.d_active) {
 143: 
 144:     case SIO:
 145:     done:
 146:         tctab.d_active = 0;
 147:         if (tctab.d_actf = bp->av_forw)
 148:             tcstart();
 149:         else
 150:             TCADDR->tccm.lobyte = SAT|GO;
 151:         iodone(bp);
 152:         return;
 153: 
 154:     case SFORW:
 155:         if (*tcdtp > bp->b_blkno)
 156:             goto setback;
 157:         if (*tcdtp < bp->b_blkno)
 158:             goto setforw;
 159:         *--tcdtp = bp->b_addr;      /* core address */
 160:         *--tcdtp = bp->b_wcount;
 161:         tccmp->lobyte = ((bp->b_xmem & 03) << 4) | IENABLE|GO
 162:             | (bp->b_flags&B_READ?RDATA:WDATA);
 163:         tctab.d_active = SIO;
 164:         return;
 165: 
 166:     case SREV:
 167:         if (*tcdtp+3 > bp->b_blkno)
 168:             goto setback;
 169:         goto setforw;
 170:     }
 171: }

Defined functions

Defined variables

Defined macros