2.9BSD - /usr/src/sys/stand/mtboot.s

   1: / tape boot program to load and transfer
   2: / the next item on the tape.
   3: 
   4: / entry is made by jsr pc,*$0
   5: / so return can be rts pc
   6: 
   7: core = 24.
   8: halt=0
   9: .. = [core*2048.]-512.
  10: start:
  11:         mov     $..,sp
  12:         mov     sp,r1
  13:         cmp     pc,r1
  14:         bhis    2f
  15:         clr     r0
  16:         cmp     (r0),$407
  17:         bne     1f
  18:         mov     $20,r0
  19: 1:
  20:         mov     (r0)+,(r1)+
  21:         cmp     r1,$core*2048.
  22:         blo     1b
  23:         jmp     (sp)
  24: 
  25: 2:
  26:         mov     $1f,*$4
  27:         mov     $340,*$6
  28:         tst     *$htcs1
  29:         mov     $htrew,rew
  30:         mov     $htread,tread
  31:         br      2f
  32: 1:
  33:         mov     $tmread,tread
  34:         mov     $tmrew,rew
  35: 2:
  36:         jsr     pc,*rew
  37:         mov     $2,tapa
  38:         mov     $-256.,wc
  39:         jsr     pc,*tread
  40: 
  41:         mov     *$2,r0
  42:         add     *$4,r0
  43:         sub     $512.,r0
  44:         asr     r0
  45:         neg     r0
  46:         bge     1f
  47: 
  48:         mov     r0,wc
  49:         mov     $3,tapa
  50:         mov     $512.,ba
  51:         jsr     pc,*tread
  52: 1:
  53:         jsr     pc,*rew
  54:         clr     r0
  55:         mov     $20,r1
  56:         mov     sp,r4
  57:         clc
  58:         ror     r4
  59: 1:
  60:         mov     (r1)+,(r0)+
  61:         sob     r4,1b
  62:         jsr     pc,*$0
  63:         br      .
  64: 
  65: htcs1 = 172440
  66: htba  = 172444
  67: htfc  = 172446
  68: htcs2 = 172450
  69: htds  = 172452
  70: httc  = 172472
  71: 
  72: P800 = 1300
  73: P1600 = 2300
  74: PIP = 20000
  75: RESET = 40
  76: MOL = 10000
  77: ERR = 40000
  78: REV = 33
  79: READ = 71
  80: REW = 7
  81: 
  82: htread:
  83: 1:
  84:         mov     ba,mtma
  85:         cmp     mtapa,tapa
  86:         beq     1f
  87:         bhi     2f
  88:         jsr     pc,hrrec
  89:         br      1b
  90: 2:
  91:         jsr     pc,htrew
  92:         br      1b
  93: 1:
  94:         mov     wc,r1
  95: 1:
  96:         jsr     pc,hrrec
  97:         add     $256.,r1
  98:         bmi     1b
  99:         rts     pc
 100: 
 101: hrrec:
 102:         mov     $htds,r0
 103:         tstb    (r0)
 104:         bpl     hrrec
 105:         bit     $PIP,(r0)
 106:         bne     hrrec
 107:         bit     $MOL,(r0)
 108:         beq     hrrec
 109:         mov     $htfc,r0
 110:         mov     $-512.,(r0)
 111:         mov     mtma,-(r0)
 112:         mov     $-256.,-(r0)
 113:         mov     $READ,-(r0)
 114: 1:
 115:         tstb    (r0)
 116:         bpl     1b
 117:         bit     $ERR,(r0)
 118:         bpl     1f
 119:         mov     $RESET,*$htcs2
 120:         mov     $-1,*$htfc
 121:         mov     $REV,(r0)
 122:         br      hrrec
 123: 1:
 124:         add     $512.,mtma
 125:         inc     mtapa
 126:         rts     pc
 127: 
 128: htrew:
 129:         mov     $RESET,*$htcs2
 130:         mov     $P800,*$httc
 131:         mov     $REW,*$htcs1
 132:         clr     mtapa
 133:         rts     pc
 134: 
 135: 
 136: mts = 172520
 137: mtc = 172522
 138: mtbrc = 172524
 139: mtcma = 172526
 140: 
 141: tmread:
 142: 1:
 143:         mov     ba,mtma
 144:         cmp     mtapa,tapa
 145:         beq     1f
 146:         bhi     2f
 147:         jsr     pc,tmrrec
 148:         br      1b
 149: 2:
 150:         jsr     pc,tmrew
 151:         br      1b
 152: 1:
 153:         mov     wc,r1
 154: 1:
 155:         jsr     pc,tmrrec
 156:         add     $256.,r1
 157:         bmi     1b
 158:         rts     pc
 159: 
 160: tmrrec:
 161:         mov     $mts,r0
 162:         bit     $2,(r0)+                / rewind status
 163:         bne     tmrrec
 164:         tstb    (r0)+           / cu ready
 165:         bpl     tmrrec
 166:         inc     r0
 167:         mov     $-512.,(r0)+    / byte count
 168:         mov     mtma,(r0)       / bus address
 169:         mov     $mtc,r0
 170:         mov     $60003,(r0)             / read 800bpi
 171: 1:
 172:         tstb    (r0)
 173:         bpl     1b
 174:         tst     (r0)+
 175:         bpl     1f
 176:         mov     $-1,(r0)
 177:         mov     $60013,-(r0)            / backspace
 178:         br      tmrrec
 179: 1:
 180:         add     $512.,mtma
 181:         inc     mtapa
 182:         rts     pc
 183: 
 184: tmrew:
 185:         mov     $60017,*$mtc
 186:         clr     mtapa
 187:         rts     pc
 188: 
 189: mtapa:  0
 190: mtma:   0
 191: tapa:   0
 192: wc:     0
 193: ba:     0
 194: rew:    0
 195: tread:  0

Defined functions