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1.1 root 1: /*
2: * Copyright (c) 1980, 1986 Regents of the University of California.
3: * All rights reserved. The Berkeley software License Agreement
4: * specifies the terms and conditions for redistribution.
5: */
6:
7: /* "@(#)htboot.c 7.1 (Berkeley) 6/5/86" */
8:
9:
10: /*
11: * VAX tape boot block for distribution tapes
12: * works on massbus tu10/te16/tu45/tu77
13: *
14: * reads a program from a tp directory on a tape and executes it
15: * program must be stripped of the header and is loaded ``bits as is''
16: * you can return to this loader via ``ret'' as you are called ``calls $0,ent''
17: */
18: .set RELOC,0x70000
19: /* a.out defines */
20: .set HDRSIZ,040 /* size of file header for VAX */
21: .set MAGIC,0410 /* file type id in header */
22: .set TSIZ,4 /* text size */
23: .set DSIZ,8 /* data size */
24: .set BSIZ,12 /* bss size */
25: .set TENT,024 /* task header entry loc */
26: /* tp directory definitions */
27: .set FILSIZ,38 /* tp direc offset for file size */
28: .set BNUM,44 /* tp dir offset for start block no. */
29: .set ENTSIZ,64 /* size of 1 TP dir entry, bytes */
30: .set PTHSIZ,32 /* size of TP path name, bytes */
31: .set BLKSIZ,512 /* tape block size, bytes */
32: .set NUMDIR,24 /* no. of dir blocks on tape */
33: .set ENTBLK,8 /* no. of dir entries per tape block */
34: /* processor registers and bits */
35: .set RXCS,32
36: .set RXDB,33
37: .set TXCS,34
38: .set TXDB,35
39: .set RXCS_DONE,0x80
40: .set TXCS_RDY,0x80
41: .set TXCS_pr,7 /* bit position of TXCS ready bit */
42: .set RXCS_pd,7 /* bit position of RXCS done bit */
43: /* MBA registers */
44: .set MBA_CSR,0 /* configuration and status register */
45: .set MBA_CR,4 /* MBA control reg */
46: .set MBA_SR,8 /* MBA status reg */
47: .set MBA_VAR,12 /* MBA virt addr reg */
48: .set MBA_BCR,16 /* MBA byte count reg */
49: .set MBA_MAP,0x800 /* start of MBA map reg's */
50: .set MRV,0x80000000
51: /* TE16/TU45/TU77 mba registers */
52: .set HTCS1,0 /* HT control 1 reg */
53: .set HTDS,4 /* status reg */
54: .set HTER,8 /* error reg */
55: .set HTAS,16 /* attention summary */
56: .set HTFC,20 /* frame count */
57: .set HTTC,36 /* HT tape control */
58: /* HT commands */
59: .set GO,1 /* GO bit */
60: .set HT_REW,6 /* rewind, on-line */
61: .set HT_DCLR,010 /* drive clear */
62: .set HT_SREV,032 /* space reverse */
63: .set HT_RCOM,070 /* read forward */
64: /* HT bits */
65: .set ERR,040000 /* composite error bit in status reg */
66: .set TCHAR,012300 /* unit 0, odd parity, PDP11, 1600 BPI NRZ, */
67: /* abort on error - for tape controller */
68: .set DRDY,0200 /* HT/drive ready in status reg */
69: .set HT_pd,7 /* bit position of HT DRDY bit */
70: .set HT_pe,14 /* bit position of HT ERROR bit */
71: /* local stack variables */
72: .set tapa,-4 /* desired tape addr */
73: .set mtapa,-8 /* current tape addr */
74: .set name,-8-PTHSIZ /* operator-typed file name */
75: /* register usage */
76: .set rMBA,r10
77: .set rHT,r11
78:
79: /* initialization */
80: init:
81: mull2 $0x80,%rHT
82: addl2 $0x400,%rHT
83: addl2 %rMBA,%rHT
84: movl $RELOC,fp /* core loc to which to move this program */
85: addl3 $name,fp,sp /* set stack pointer, leaving room for locals */
86: clrl r0
87: 1:
88: movc3 $end,(r0),(fp) /* move boot up to relocated position */
89: jmp start+RELOC
90: start:
91: movl $1,MBA_CR(%rMBA) /* MBA init */
92: movl $TCHAR,HTTC(%rHT) /* drive no., etc. */
93: movl $HT_DCLR+GO,HTCS1(%rHT) /* drive clear */
94: bsbw rew /* rewind input tape */
95: movab name(fp),r4 /* start of filename storage */
96: movzbl $'=,r0 /* prompt character */
97: bsbw putc /* output char to main console */
98: /* read in a file name */
99: movl r4,r1 /* loc at which to store file name */
100: nxtc:
101: bsbw getc /* get input char's in file name */
102: cmpb r0,$012 /* terminator ? */
103: beql nullc
104: movb r0,(r1)+
105: brb nxtc
106: nullc:
107: subl3 r4,r1,r9 /* size of path name */
108: beql start /* dumb operator */
109: clrb (r1)+
110: incl r9
111: /* user-specified TP filename has been stored at name(fp) */
112: /* read in entire tp directory contents into low core */
113: dirred:
114: movl $8,tapa(fp) /* tp directory starts at block 8 */
115: movl $(NUMDIR*BLKSIZ),r6 /* no. bytes in total dir */
116: bsbw taper /* read no. bytes indicated */
117: /* search entire directory for user-specified file name */
118: clrl r5 /* dir buff loc = 0 */
119: nxtdir:
120: cmpc3 r9,(r5),(r4) /* see if dir entry matches filename */
121: beql fndfil /* found match */
122: acbl $NUMDIR*BLKSIZ-1,$ENTSIZ,r5,nxtdir
123: /* see if done with tp dir */
124: brw start /* entry not in directory; start over */
125: /* found desired tp dir entry */
126: fndfil:
127: movzwl BNUM(r5),tapa(fp) /* start block no., 2 bytes */
128: addl2 $7,tapa(fp) /* skip 7 boot blocks */
129: movzwl FILSIZ(r5),r6 /* low 2 bytes file size */
130: insv FILSIZ-1(r5),$16,$8,r6 /* file size, high byte */
131: cmpl r6,$RELOC-512 /* check if file fits below stack */
132: blss filok /* file o.k. */
133: brw start /* file too large */
134: /* time to read in desired file from tape */
135: filok:
136: movl r6,r7 /* save r6 */
137: bsbb taper
138: bsbw rew
139: /* clear core */
140: subl3 r7,$RELOC-4,r0 /* no. bytes to clear */
141: 1:
142: clrb (r7)+
143: sobgtr r0,1b
144: /* time to jump to start of file & execute */
145: addl3 $20,fp,ap
146: clrl r5
147: calls $0,(r5)
148: brw start
149: /* taper: movcTAPE (r6),tapa(fp),0 */
150: rew2:
151: bsbb rew /* beginning of tape */
152: taper0:
153: bsbb rrec /* advance 1 block; never want blk0 */
154: taper:
155: clrl r0 /* page no. */
156: cmpl mtapa(fp),tapa(fp) /* current position .vs. desired */
157: bgtr rew2
158: blss taper0
159: 1:
160: bsbb rrec
161: acbl $1,$-BLKSIZ,r6,1b
162: rsb
163: /* rew: rewind the tape */
164: rew:
165: clrl mtapa(fp) /* current position */
166: movl $HT_REW+GO,HTCS1(%rHT) /* rewind */
167: rsb
168: /* rrec: read 1 block from mag tape into page (r0) */
169: rrec:
170: /* pushl r0; movzbl $'r,r0; bsbw putc; movl (sp)+,r0; */
171: movl HTDS(%rHT),r2
172: bbc $HT_pd,r2,rrec /* HT & drive ready ? */
173: movl $-BLKSIZ,MBA_BCR(%rMBA)
174: bisl3 $MRV,r0,MBA_MAP(%rMBA)
175: clrl MBA_VAR(%rMBA)
176: movl $HT_RCOM+GO,HTCS1(%rHT) /* read forward */
177: 1:
178: movl HTDS(%rHT),r2
179: bbc $HT_pd,r2,1b
180: movl HTER(%rHT),r2
181: bbc $HT_pe,r2,2f /* any read errors ? */
182: clrl HTDS(%rHT) /* clear status - try to recover */
183: mnegl $1,HTFC(%rHT) /* frame count for backspace */
184: movl $HT_SREV+GO,HTCS1(%rHT) /* space reverse */
185: brb rrec
186: 2:
187: incl r0 /* next page no. */
188: incl mtapa(fp) /* mag tape block position */
189: rsb
190: getc:
191: mfpr $RXCS,r0
192: bbc $RXCS_pd,r0,getc /* receiver ready ? */
193: mfpr $RXDB,r0
194: extzv $0,$7,r0,r0
195: cmpb r0,$015
196: bneq putc
197: bsbb putc
198: movb $0,r0
199: bsbb putc
200: movb $012,r0
201: putc:
202: mfpr $TXCS,r2
203: bbc $TXCS_pr,r2,putc /* transmitter ready ? */
204: extzv $0,$7,r0,r0
205: mtpr r0,$TXDB
206: rsb
207: end:
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