1 /* mtboot.c 6.1 83/07/29 */ 2 3 /* 4 * VAX tape boot block for distribution tapes 5 * works on massbys tu78 6 * 7 * reads a program from a tp directory on a tape and executes it 8 * program must be stripped of the header and is loaded ``bits as is'' 9 * you can return to this loader via ``ret'' as you are called ``calls $0,ent'' 10 * 11 * Based on similar driver for tm03 formatter. 12 * Local modifications by Jeffrey R. Schwab June, 1982 13 * Purdue University Computing Center 14 */ 15 .set RELOC,0x70000 16 /* a.out defines */ 17 .set HDRSIZ,040 /* size of file header for VAX */ 18 .set MAGIC,0410 /* file type id in header */ 19 .set TSIZ,4 /* text size */ 20 .set DSIZ,8 /* data size */ 21 .set BSIZ,12 /* bss size */ 22 .set TENT,024 /* task header entry loc */ 23 /* tp directory definitions */ 24 .set FILSIZ,38 /* tp direc offset for file size */ 25 .set BNUM,44 /* tp dir offset for start block no. */ 26 .set ENTSIZ,64 /* size of 1 TP dir entry, bytes */ 27 .set PTHSIZ,32 /* size of TP path name, bytes */ 28 .set BLKSIZ,512 /* tape block size, bytes */ 29 .set NUMDIR,24 /* no. of dir blocks on tape */ 30 .set ENTBLK,8 /* no. of dir entries per tape block */ 31 /* processor registers and bits */ 32 .set RXCS,32 33 .set RXDB,33 34 .set TXCS,34 35 .set TXDB,35 36 .set RXCS_DONE,0x80 37 .set TXCS_RDY,0x80 38 .set TXCS_pr,7 /* bit position of TXCS ready bit */ 39 .set RXCS_pd,7 /* bit position of RXCS done bit */ 40 /* MBA registers */ 41 .set MBA_CSR,0 /* configuration and status register */ 42 .set MBA_CR,4 /* MBA control reg */ 43 .set MBA_SR,8 /* MBA status reg */ 44 .set MBA_VAR,12 /* MBA virt addr reg */ 45 .set MBA_BCR,16 /* MBA byte count reg */ 46 .set MBA_MAP,0x800 /* start of MBA map reg's */ 47 .set MRV,0x80000000 48 .set MBA_bsy,31 /* massbus busy */ 49 /* TU78 mba registers */ 50 .set MTCS,0 /* MT data transfer control reg */ 51 .set MTER,4 /* data transfer error status reg */ 52 .set MTRC,8 /* record count */ 53 .set MTAS,16 /* attention summary */ 54 .set MTBC,20 /* byte count */ 55 .set MTNER,44 /* non data transfer error status reg */ 56 .set MTNCS,48 /* non data transfer control reg */ 57 .set MTID,68 /* internal data reg */ 58 /* MT commands */ 59 .set GO,1 /* GO bit */ 60 .set MT_REW,6 /* rewind, on-line */ 61 .set MT_RCOM,070 /* read forward */ 62 /* MT bits */ 63 .set MT_rdy,15 /* controller ready */ 64 .set MT_rec,2 /* bit for single record count */ 65 .set MT_rcnt,4 /* record count for single record (shifted) */ 66 .set MT_erc,0xffffffc0 /* error code mask */ 67 .set MT_done,1 /* proper completion code */ 68 /* local stack variables */ 69 .set tapa,-4 /* desired tape addr */ 70 .set mtapa,-8 /* current tape addr */ 71 .set name,-8-PTHSIZ /* operator-typed file name */ 72 /* register usage */ 73 .set rMBA,r10 74 .set rMT,r11 75 76 /* initialization */ 77 init: 78 mull2 $0x80,%rMT 79 addl2 $0x400,%rMT 80 addl2 %rMBA,%rMT 81 movl $RELOC,fp /* core loc to which to move this program */ 82 addl3 $name,fp,sp /* set stack pointer, leaving room for locals */ 83 clrl r0 84 1: 85 movc3 $end,(r0),(fp) /* move boot up to relocated position */ 86 jmp start+RELOC 87 start: 88 movl $1,MBA_CR(%rMBA) /* MBA init */ 89 1: 90 movl MTID(%rMT),r2 /* wait for tape controller to ready */ 91 bbc $MT_rdy,r2,1b /* after massbus init */ 92 bsbw rew /* rewind input tape */ 93 movab name(fp),r4 /* start of filename storage */ 94 movzbl $'=,r0 /* prompt character */ 95 bsbw putc /* output char to main console */ 96 /* read in a file name */ 97 movl r4,r1 /* loc at which to store file name */ 98 nxtc: 99 bsbw getc /* get input char's in file name */ 100 cmpb r0,$012 /* terminator ? */ 101 beql nullc 102 movb r0,(r1)+ 103 brb nxtc 104 nullc: 105 subl3 r4,r1,r9 /* size of path name */ 106 beql start /* dumb operator */ 107 clrb (r1)+ 108 incl r9 109 /* user-specified TP filename has been stored at name(fp) */ 110 /* read in entire tp directory contents into low core */ 111 dirred: 112 movl $8,tapa(fp) /* tp directory starts at block 8 */ 113 movl $(NUMDIR*BLKSIZ),r6 /* no. bytes in total dir */ 114 bsbw taper /* read no. bytes indicated */ 115 /* search entire directory for user-specified file name */ 116 clrl r5 /* dir buff loc = 0 */ 117 nxtdir: 118 cmpc3 r9,(r5),(r4) /* see if dir entry matches filename */ 119 beql fndfil /* found match */ 120 acbl $NUMDIR*BLKSIZ-1,$ENTSIZ,r5,nxtdir 121 /* see if done with tp dir */ 122 brw start /* entry not in directory; start over */ 123 /* found desired tp dir entry */ 124 fndfil: 125 movzwl BNUM(r5),tapa(fp) /* start block no., 2 bytes */ 126 addl2 $7,tapa(fp) /* skip 7 boot blocks */ 127 movzwl FILSIZ(r5),r6 /* low 2 bytes file size */ 128 insv FILSIZ-1(r5),$16,$8,r6 /* file size, high byte */ 129 cmpl r6,$RELOC-512 /* check if file fits below stack */ 130 blss filok /* file o.k. */ 131 brw start /* file too large */ 132 /* time to read in desired file from tape */ 133 filok: 134 movl r6,r7 /* save r6 */ 135 bsbb taper 136 bsbw rew 137 /* clear core */ 138 subl3 r7,$RELOC-4,r0 /* no. bytes to clear */ 139 1: 140 clrb (r7)+ 141 sobgtr r0,1b 142 /* time to jump to start of file & execute */ 143 addl3 $20,fp,ap 144 clrl r5 145 calls $0,(r5) 146 brw start 147 /* taper: movcTAPE (r6),tapa(fp),0 */ 148 rew2: 149 bsbb rew /* beginning of tape */ 150 taper0: 151 bsbb rrec /* advance 1 block; never want blk0 */ 152 taper: 153 clrl r0 /* page no. */ 154 cmpl mtapa(fp),tapa(fp) /* current position .vs. desired */ 155 bgtr rew2 156 blss taper0 157 1: 158 bsbb rrec 159 acbl $1,$-BLKSIZ,r6,1b 160 rsb 161 /* rew: rewind the tape */ 162 rew: 163 clrl mtapa(fp) /* current position */ 164 movl MTNER(%rMT),r2 /* read non-data status */ 165 movl MTAS(%rMT),MTAS(%rMT) /* and clear any attention bits */ 166 movl $MT_REW+GO,MTNCS(%rMT) /* rewind command and go bit */ 167 1: 168 movl MTAS(%rMT),r2 /* check attention bits */ 169 beql 1b /* loop if attention not yet set */ 170 movl MTNER(%rMT),r2 /* read non-data status */ 171 movl MTAS(%rMT),MTAS(%rMT) /* and clear any attention bits */ 172 bicl2 $MT_erc,r2 /* isolate error condition */ 173 subl2 $MT_done,r2 /* check with completion condition */ 174 bneq 1b /* wait for completion attention */ 175 rsb 176 /* rrec: read 1 block from mag tape into page (r0) */ 177 rrec: 178 /* pushl r0; movzbl $'r,r0; bsbw putc; movl (sp)+,r0; */ 179 movl MTNER(%rMT),r2 /* read non-data status */ 180 movl MTAS(%rMT),MTAS(%rMT) /* and clear any attention bits */ 181 movl $-BLKSIZ,MBA_BCR(%rMBA) 182 bisl3 $MRV,r0,MBA_MAP(%rMBA) 183 clrl MBA_VAR(%rMBA) 184 movl $BLKSIZ,MTBC(%rMT) /* set byte count */ 185 bisl2 $MT_rcnt,MTRC(%rMT) /* set record count */ 186 movl $MT_RCOM+GO,MTCS(%rMT) /* load read command */ 187 1: 188 movl MBA_SR(%rMBA),r2 /* load mba status reg */ 189 bbs $MBA_bsy,r2,1b /* wait for mba to go non-busy */ 190 movl MTRC(%rMT),r2 /* fetch record count */ 191 bbs $MT_rec,r2,rrec /* retry read if we did not read a record */ 192 movl MTER(%rMT),r2 /* load data transfer error status */ 193 bicl2 $MT_erc,r2 /* isolate status value */ 194 subl2 $MT_done,r2 /* compare with successful read */ 195 bneq rrec /* load to try read again */ 196 197 incl r0 /* next page no. */ 198 incl mtapa(fp) /* mag tape block position */ 199 rsb 200 getc: 201 mfpr $RXCS,r0 202 bbc $RXCS_pd,r0,getc /* receiver ready ? */ 203 mfpr $RXDB,r0 204 extzv $0,$7,r0,r0 205 cmpb r0,$015 206 bneq putc 207 bsbb putc 208 movb $0,r0 209 bsbb putc 210 movb $012,r0 211 putc: 212 mfpr $TXCS,r2 213 bbc $TXCS_pr,r2,putc /* transmitter ready ? */ 214 extzv $0,$7,r0,r0 215 mtpr r0,$TXDB 216 rsb 217 end: 218