UNIX 7th Ed. - /usr/sys/dev/tc.c

   1: #
   2: 
   3: /*
   4:  * TC-11 DECtape driver
   5:  */
   6: 
   7: #include "../h/param.h"
   8: #include "../h/conf.h"
   9: #include "../h/buf.h"
  10: #include "../h/dir.h"
  11: #include "../h/user.h"
  12: 
  13: struct device {
  14:     int tccsr;
  15:     union wb {
  16:         int w;
  17:         char    b[2];
  18:     } tccm;
  19:     int tcwc;
  20:     int tcba;
  21:     int tcdt;
  22: };
  23: 
  24: struct  buf tctab;
  25: char    tcper[8];
  26: 
  27: #define TCADDR  ((struct device *) 0177340)
  28: #define NTCBLK  578
  29: 
  30: #define TAPERR  0100000
  31: #define TREV    04000
  32: #define READY   0200
  33: #define IENABLE 0100
  34: #define UPS 0200
  35: #define ENDZ    0100000
  36: #define BLKM    02000
  37: #define ILGOP   010000
  38: #define SELERR  04000
  39: 
  40: #define SAT 0
  41: #define RNUM    02
  42: #define RDATA   04
  43: #define SST 010
  44: #define WDATA   014
  45: #define GO  01
  46: 
  47: #define SFORW   1
  48: #define SREV    2
  49: #define SIO 3
  50: 
  51: tcclose(dev)
  52: {
  53:     bflush(dev);
  54:     tcper[dev&07] = 0;
  55: }
  56: 
  57: tcstrategy(bp)
  58: register struct buf *bp;
  59: {
  60: 
  61:     if(bp->b_flags&B_PHYS)
  62:         mapalloc(bp);
  63:     bp->b_resid = 0;
  64:     if(bp->b_blkno >= NTCBLK || tcper[minor(bp->b_dev)&07]) {
  65:         bp->b_flags |= B_ERROR;
  66:         iodone(bp);
  67:         return;
  68:     }
  69:     bp->av_forw = 0;
  70:     spl6();
  71:     if (tctab.b_actf==0)
  72:         tctab.b_actf = bp;
  73:     else
  74:         tctab.b_actl->av_forw = bp;
  75:     tctab.b_actl = bp;
  76:     if (tctab.b_active==0)
  77:         tcstart();
  78:     spl0();
  79: }
  80: 
  81: tcstart()
  82: {
  83:     register struct buf *bp;
  84:     register int com;
  85:     register union wb *tccmp;
  86: 
  87: loop:
  88:     tccmp = &TCADDR->tccm;
  89:     if ((bp = tctab.b_actf) == 0)
  90:         return;
  91:     if(tcper[minor(bp->b_dev)&07]) {
  92:         if((tctab.b_actf = bp->av_forw) == 0)
  93:             tccmp->b[0] = SAT|GO;
  94:         bp->b_flags |= B_ERROR;
  95:         iodone(bp);
  96:         goto loop;
  97:     }
  98:     if ((tccmp->b[1]&07) != minor(bp->b_dev))
  99:         tccmp->b[0] = SAT|GO;
 100:     tctab.b_errcnt = 20;
 101:     tctab.b_active = SFORW;
 102:     com = (minor(bp->b_dev)<<8) | IENABLE|RNUM|GO;
 103:     if ((TCADDR->tccsr & UPS) == 0) {
 104:         com |= TREV;
 105:         tctab.b_active = SREV;
 106:     }
 107:     tccmp->w = com;
 108: }
 109: 
 110: tcintr()
 111: {
 112:     register struct buf *bp;
 113:     register union wb *tccmp;
 114:     register int *tcdtp;
 115: 
 116:     tccmp = &TCADDR->tccm;
 117:     tcdtp = &TCADDR->tccsr;
 118:     bp = tctab.b_actf;
 119:     if (tccmp->w&TAPERR) {
 120:         if((*tcdtp&(ENDZ|BLKM)) == 0)
 121:             deverror(bp, *tcdtp, 0);
 122:         if(*tcdtp & (ILGOP|SELERR)) {
 123:             tcper[bp->b_dev&07]++;
 124:             tctab.b_errcnt = 0;
 125:         }
 126:         tccmp->w &= ~TAPERR;
 127:         if (--tctab.b_errcnt == 0) {
 128:             bp->b_flags |= B_ERROR;
 129:             goto done;
 130:         }
 131:         if (tccmp->w&TREV) {
 132:         setforw:
 133:             tctab.b_active = SFORW;
 134:             tccmp->w &= ~TREV;
 135:         } else {
 136:         setback:
 137:             tctab.b_active = SREV;
 138:             tccmp->w |= TREV;
 139:         }
 140:         tccmp->b[0] = IENABLE|RNUM|GO;
 141:         return;
 142:     }
 143:     tcdtp = &TCADDR->tcdt;
 144:     switch (tctab.b_active) {
 145: 
 146:     case SIO:
 147:     done:
 148:         tctab.b_active = 0;
 149:         if (tctab.b_actf = bp->av_forw)
 150:             tcstart();
 151:         else
 152:             TCADDR->tccm.b[0] = SAT|GO;
 153:         iodone(bp);
 154:         return;
 155: 
 156:     case SFORW:
 157:         if (*tcdtp > bp->b_blkno)
 158:             goto setback;
 159:         if (*tcdtp < bp->b_blkno)
 160:             goto setforw;
 161:         *--tcdtp = (int)bp->b_un.b_addr;    /* core address */
 162:         *--tcdtp = -(bp->b_bcount>>1);
 163:         tccmp->b[0] = ((bp->b_xmem & 03) << 4) | IENABLE|GO
 164:             | (bp->b_flags&B_READ?RDATA:WDATA);
 165:         tctab.b_active = SIO;
 166:         return;
 167: 
 168:     case SREV:
 169:         if (*tcdtp+3 > bp->b_blkno)
 170:             goto setback;
 171:         goto setforw;
 172:     }
 173: }

Defined functions

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Defined macros