xref: /original-bsd/sys/vax/mdec/mtboot.c (revision 6ef710fc)
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 /* "@(#)mtboot.c	7.1 (Berkeley) 06/05/86" */
8 
9 /*
10  * VAX tape boot block for distribution tapes
11  * works on massbys tu78
12  *
13  * reads a program from a tp directory on a tape and executes it
14  * program must be stripped of the header and is loaded ``bits as is''
15  * you can return to this loader via ``ret'' as you are called ``calls $0,ent''
16  *
17  * Based on similar driver for tm03 formatter.
18  * Local modifications by Jeffrey R. Schwab	June, 1982
19  *				Purdue University Computing Center
20  */
21 	.set	RELOC,0x70000
22 /* a.out defines */
23 	.set	HDRSIZ,040	/* size of file header for VAX */
24 	.set	MAGIC,0410	/* file type id in header */
25 	.set	TSIZ,4		/* text size */
26 	.set	DSIZ,8		/* data size */
27 	.set	BSIZ,12		/* bss size */
28 	.set	TENT,024	/* task header entry loc */
29 /* tp directory definitions */
30 	.set	FILSIZ,38	/* tp direc offset for file size */
31 	.set	BNUM,44		/* tp dir offset for start block no. */
32 	.set	ENTSIZ,64	/* size of 1 TP dir entry, bytes */
33 	.set	PTHSIZ,32	/* size of TP path name, bytes */
34 	.set	BLKSIZ,512	/* tape block size, bytes */
35 	.set	NUMDIR,24	/* no. of dir blocks on tape */
36 	.set	ENTBLK,8	/* no. of dir entries per tape block */
37 /* processor registers and bits */
38 	.set	RXCS,32
39 	.set	RXDB,33
40 	.set	TXCS,34
41 	.set	TXDB,35
42 	.set	RXCS_DONE,0x80
43 	.set	TXCS_RDY,0x80
44 	.set	TXCS_pr,7	/* bit position of TXCS ready bit */
45 	.set	RXCS_pd,7	/* bit position of RXCS done bit */
46 /* MBA registers */
47 	.set	MBA_CSR,0	/* configuration and status register */
48 	.set	MBA_CR,4	/* MBA control reg */
49 	.set	MBA_SR,8	/* MBA status reg */
50 	.set	MBA_VAR,12	/* MBA virt addr reg */
51 	.set	MBA_BCR,16	/* MBA byte count reg */
52 	.set	MBA_MAP,0x800	/* start of MBA map reg's */
53 	.set	MRV,0x80000000
54 	.set	MBA_bsy,31	/* massbus busy */
55 /* TU78 mba registers */
56 	.set	MTCS,0		/* MT data transfer control reg */
57 	.set	MTER,4		/* data transfer error status reg */
58 	.set	MTRC,8		/* record count */
59 	.set	MTAS,16		/* attention summary */
60 	.set	MTBC,20		/* byte count */
61 	.set	MTNER,44	/* non data transfer error status reg */
62 	.set	MTNCS,48	/* non data transfer control reg */
63 	.set	MTID,68		/* internal data reg */
64 /* MT commands */
65 	.set	GO,1		/* GO bit */
66 	.set	MT_REW,6	/* rewind, on-line */
67 	.set	MT_RCOM,070	/* read forward */
68 /* MT bits */
69 	.set	MT_rdy,15	/* controller ready */
70 	.set	MT_rec,2	/* bit for single record count */
71 	.set	MT_rcnt,4	/* record count for single record (shifted) */
72 	.set	MT_erc,0xffffffc0	/* error code mask */
73 	.set	MT_done,1	/* proper completion code */
74 /* local stack variables */
75 	.set	tapa,-4		/* desired tape addr */
76 	.set	mtapa,-8	/* current tape addr */
77 	.set	name,-8-PTHSIZ	/* operator-typed file name */
78 /* register usage */
79 	.set	rMBA,r10
80 	.set	rMT,r11
81 
82 /* initialization */
83 init:
84 	mull2	$0x80,%rMT
85 	addl2	$0x400,%rMT
86 	addl2	%rMBA,%rMT
87 	movl	$RELOC,fp	/* core loc to which to move this program */
88 	addl3	$name,fp,sp	/* set stack pointer, leaving room for locals */
89 	clrl	r0
90 1:
91 	movc3	$end,(r0),(fp)	/* move boot up to relocated position */
92 	jmp	start+RELOC
93 start:
94 	movl	$1,MBA_CR(%rMBA)	/* MBA init */
95 1:
96 	movl	MTID(%rMT),r2		/* wait for tape controller to ready */
97 	bbc	$MT_rdy,r2,1b		/* after massbus init */
98 	bsbw	rew			/* rewind input tape */
99 	movab	name(fp),r4		/* start of filename storage */
100 	movzbl	$'=,r0			/* prompt character */
101 	bsbw	putc			/* output char to main console */
102 /* read in a file name */
103 	movl	r4,r1			/* loc at which to store file name */
104 nxtc:
105 	bsbw	getc			/* get input char's in file name */
106 	cmpb	r0,$012			/* terminator ? */
107 	beql	nullc
108 	movb	r0,(r1)+
109 	brb	nxtc
110 nullc:
111 	subl3	r4,r1,r9		/* size of path name */
112 	beql	start			/* dumb operator */
113 	clrb	(r1)+
114 	incl	r9
115 /* user-specified TP filename has been stored at name(fp) */
116 /* read in entire tp directory contents into low core */
117 dirred:
118 	movl	$8,tapa(fp)		/* tp directory starts at block 8 */
119 	movl	$(NUMDIR*BLKSIZ),r6	/* no. bytes in total dir */
120 	bsbw	taper			/* read no. bytes indicated */
121 /* search entire directory for user-specified file name */
122 	clrl	r5			/* dir buff loc = 0 */
123 nxtdir:
124 	cmpc3	r9,(r5),(r4)		/* see if dir entry matches filename */
125 	beql	fndfil			/* found match */
126 	acbl	$NUMDIR*BLKSIZ-1,$ENTSIZ,r5,nxtdir
127 					/* see if done with tp dir */
128 	brw	start			/* entry not in directory; start over */
129 /* found desired tp dir entry */
130 fndfil:
131 	movzwl	BNUM(r5),tapa(fp)	/* start block no., 2 bytes */
132 	addl2	$7,tapa(fp)		/* skip 7 boot blocks */
133 	movzwl	FILSIZ(r5),r6		/* low 2 bytes file size */
134 	insv	FILSIZ-1(r5),$16,$8,r6  /* file size, high byte */
135 	cmpl	r6,$RELOC-512		/* check if file fits below stack */
136 	blss	filok 			/* file o.k. */
137 	brw	start			/* file too large */
138 /* time to read in desired file from tape */
139 filok:
140 	movl	r6,r7			/* save r6 */
141 	bsbb	taper
142 	bsbw	rew
143 /* clear core */
144 	subl3	r7,$RELOC-4,r0		/* no. bytes to clear */
145 1:
146 	clrb	(r7)+
147 	sobgtr	r0,1b
148 /* time to jump to start of file & execute */
149 	addl3	$20,fp,ap
150 	clrl	r5
151 	calls	$0,(r5)
152 	brw	start
153 /* taper: movcTAPE (r6),tapa(fp),0 */
154 rew2:
155 	bsbb	rew			/* beginning of tape */
156 taper0:
157 	bsbb	rrec			/* advance 1 block; never want blk0 */
158 taper:
159 	clrl	r0			/* page no. */
160 	cmpl	mtapa(fp),tapa(fp)	/* current position .vs. desired */
161 	bgtr	rew2
162 	blss	taper0
163 1:
164 	bsbb	rrec
165 	acbl	$1,$-BLKSIZ,r6,1b
166 	rsb
167 /* rew: rewind the tape */
168 rew:
169 	clrl	mtapa(fp)		/* current position */
170 	movl	MTNER(%rMT),r2		/* read non-data status */
171  	movl	MTAS(%rMT),MTAS(%rMT)	/* and clear any attention bits */
172 	movl	$MT_REW+GO,MTNCS(%rMT)	/* rewind command and go bit */
173 1:
174 	movl	MTAS(%rMT),r2		/* check attention bits */
175 	beql	1b			/* loop if attention not yet set */
176 	movl	MTNER(%rMT),r2		/* read non-data status */
177 	movl	MTAS(%rMT),MTAS(%rMT)	/* and clear any attention bits */
178 	bicl2	$MT_erc,r2		/* isolate error condition */
179 	subl2	$MT_done,r2		/* check with completion condition */
180 	bneq	1b			/* wait for completion attention */
181 	rsb
182 /* rrec: read 1 block from mag tape into page (r0) */
183 rrec:
184 	/* pushl r0; movzbl $'r,r0; bsbw putc; movl (sp)+,r0; */
185 	movl	MTNER(%rMT),r2		/* read non-data status */
186 	movl	MTAS(%rMT),MTAS(%rMT)	/* and clear any attention bits */
187 	movl	$-BLKSIZ,MBA_BCR(%rMBA)
188 	bisl3	$MRV,r0,MBA_MAP(%rMBA)
189 	clrl	MBA_VAR(%rMBA)
190 	movl	$BLKSIZ,MTBC(%rMT)	/* set byte count */
191 	bisl2	$MT_rcnt,MTRC(%rMT)	/* set record count */
192 	movl	$MT_RCOM+GO,MTCS(%rMT)	/* load read command */
193 1:
194 	movl	MBA_SR(%rMBA),r2	/* load mba status reg */
195 	bbs	$MBA_bsy,r2,1b		/* wait for mba to go non-busy */
196 	movl	MTRC(%rMT),r2		/* fetch record count */
197 	bbs	$MT_rec,r2,rrec		/* retry read if we did not read a record */
198 	movl	MTER(%rMT),r2		/* load data transfer error status */
199 	bicl2	$MT_erc,r2		/* isolate status value */
200 	subl2	$MT_done,r2		/* compare with successful read */
201 	bneq	rrec			/* load to try read again */
202 
203 	incl	r0			/* next page no. */
204 	incl	mtapa(fp)		/* mag tape block position */
205 	rsb
206 getc:
207 	mfpr	$RXCS,r0
208 	bbc	$RXCS_pd,r0,getc	/* receiver ready ? */
209 	mfpr	$RXDB,r0
210 	extzv	$0,$7,r0,r0
211 	cmpb	r0,$015
212 	bneq	putc
213 	bsbb	putc
214 	movb	$0,r0
215 	bsbb	putc
216 	movb	$012,r0
217 putc:
218 	mfpr	$TXCS,r2
219 	bbc	$TXCS_pr,r2,putc	/* transmitter ready ? */
220 	extzv	$0,$7,r0,r0
221 	mtpr	r0,$TXDB
222 	rsb
223 end:
224