1 /* mtboot.c 4.1 83/02/16 */ 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 .set MT_atn,0 /* attention bit for drive 0 */ 69 /* local stack variables */ 70 .set tapa,-4 /* desired tape addr */ 71 .set mtapa,-8 /* current tape addr */ 72 .set name,-8-PTHSIZ /* operator-typed file name */ 73 /* register usage */ 74 .set rMBA,r10 75 .set rMT,r11 76 77 /* initialization */ 78 init: 79 mull2 $0x80,%rMT 80 addl2 $0x400,%rMT 81 addl2 %rMBA,%rMT 82 movl $RELOC,fp /* core loc to which to move this program */ 83 addl3 $name,fp,sp /* set stack pointer, leaving room for locals */ 84 clrl r0 85 1: 86 movc3 $end,(r0),(fp) /* move boot up to relocated position */ 87 jmp start+RELOC 88 start: 89 movl $1,MBA_CR(%rMBA) /* MBA init */ 90 1: 91 movl MTID(%rMT),r2 /* wait for tape controller to ready */ 92 bbc $MT_rdy,r2,1b /* after massbus init */ 93 bsbw rew /* rewind input tape */ 94 movab name(fp),r4 /* start of filename storage */ 95 movzbl $'=,r0 /* prompt character */ 96 bsbw putc /* output char to main console */ 97 /* read in a file name */ 98 movl r4,r1 /* loc at which to store file name */ 99 nxtc: 100 bsbw getc /* get input char's in file name */ 101 cmpb r0,$012 /* terminator ? */ 102 beql nullc 103 movb r0,(r1)+ 104 brb nxtc 105 nullc: 106 subl3 r4,r1,r9 /* size of path name */ 107 beql start /* dumb operator */ 108 clrb (r1)+ 109 incl r9 110 /* user-specified TP filename has been stored at name(fp) */ 111 /* read in entire tp directory contents into low core */ 112 dirred: 113 movl $8,tapa(fp) /* tp directory starts at block 8 */ 114 movl $(NUMDIR*BLKSIZ),r6 /* no. bytes in total dir */ 115 bsbw taper /* read no. bytes indicated */ 116 /* search entire directory for user-specified file name */ 117 clrl r5 /* dir buff loc = 0 */ 118 nxtdir: 119 cmpc3 r9,(r5),(r4) /* see if dir entry matches filename */ 120 beql fndfil /* found match */ 121 acbl $NUMDIR*BLKSIZ-1,$ENTSIZ,r5,nxtdir 122 /* see if done with tp dir */ 123 brw start /* entry not in directory; start over */ 124 /* found desired tp dir entry */ 125 fndfil: 126 movzwl BNUM(r5),tapa(fp) /* start block no., 2 bytes */ 127 addl2 $7,tapa(fp) /* skip 7 boot blocks */ 128 movzwl FILSIZ(r5),r6 /* low 2 bytes file size */ 129 insv FILSIZ-1(r5),$16,$8,r6 /* file size, high byte */ 130 cmpl r6,$RELOC-512 /* check if file fits below stack */ 131 blss filok /* file o.k. */ 132 brw start /* file too large */ 133 /* time to read in desired file from tape */ 134 filok: 135 movl r6,r7 /* save r6 */ 136 bsbb taper 137 bsbw rew 138 /* clear core */ 139 subl3 r7,$RELOC-4,r0 /* no. bytes to clear */ 140 1: 141 clrb (r7)+ 142 sobgtr r0,1b 143 /* time to jump to start of file & execute */ 144 addl3 $20,fp,ap 145 clrl r5 146 calls $0,(r5) 147 brw start 148 /* taper: movcTAPE (r6),tapa(fp),0 */ 149 rew2: 150 bsbb rew /* beginning of tape */ 151 taper0: 152 bsbb rrec /* advance 1 block; never want blk0 */ 153 taper: 154 clrl r0 /* page no. */ 155 cmpl mtapa(fp),tapa(fp) /* current position .vs. desired */ 156 bgtr rew2 157 blss taper0 158 1: 159 bsbb rrec 160 acbl $1,$-BLKSIZ,r6,1b 161 rsb 162 /* rew: rewind the tape */ 163 rew: 164 clrl mtapa(fp) /* current position */ 165 movl MTNER(%rMT),r2 /* read non-data status */ 166 movl MTAS(%rMT),MTAS(%rMT) /* and clear any attention bits */ 167 movl $MT_REW+GO,MTNCS(%rMT) /* rewind command and go bit */ 168 1: 169 movl MTAS(%rMT),r2 /* check attention bits */ 170 bbc $MT_atn,r2,1b /* loop if attention not yet set */ 171 movl MTNER(%rMT),r2 /* read non-data status */ 172 movl MTAS(%rMT),MTAS(%rMT) /* and clear any attention bits */ 173 bicl2 $MT_erc,r2 /* isolate error condition */ 174 subl2 $MT_done,r2 /* check with completion condition */ 175 bneq 1b /* wait for completion attention */ 176 rsb 177 /* rrec: read 1 block from mag tape into page (r0) */ 178 rrec: 179 /* pushl r0; movzbl $'r,r0; bsbw putc; movl (sp)+,r0; */ 180 movl MTNER(%rMT),r2 /* read non-data status */ 181 movl MTAS(%rMT),MTAS(%rMT) /* and clear any attention bits */ 182 movl $-BLKSIZ,MBA_BCR(%rMBA) 183 bisl3 $MRV,r0,MBA_MAP(%rMBA) 184 clrl MBA_VAR(%rMBA) 185 movl $BLKSIZ,MTBC(%rMT) /* set byte count */ 186 bisl2 $MT_rcnt,MTRC(%rMT) /* set record count */ 187 movl $MT_RCOM+GO,MTCS(%rMT) /* load read command */ 188 1: 189 movl MBA_SR(%rMBA),r2 /* load mba status reg */ 190 bbs $MBA_bsy,r2,1b /* wait for mba to go non-busy */ 191 movl MTRC(%rMT),r2 /* fetch record count */ 192 bbs $MT_rec,r2,rrec /* retry read if we did not read a record */ 193 movl MTER(%rMT),r2 /* load data transfer error status */ 194 bicl2 $MT_erc,r2 /* isolate status value */ 195 subl2 $MT_done,r2 /* compare with successful read */ 196 bneq rrec /* load to try read again */ 197 198 incl r0 /* next page no. */ 199 incl mtapa(fp) /* mag tape block position */ 200 rsb 201 getc: 202 mfpr $RXCS,r0 203 bbc $RXCS_pd,r0,getc /* receiver ready ? */ 204 mfpr $RXDB,r0 205 extzv $0,$7,r0,r0 206 cmpb r0,$015 207 bneq putc 208 bsbb putc 209 movb $0,r0 210 bsbb putc 211 movb $012,r0 212 putc: 213 mfpr $TXCS,r2 214 bbc $TXCS_pr,r2,putc /* transmitter ready ? */ 215 extzv $0,$7,r0,r0 216 mtpr r0,$TXDB 217 rsb 218 end: 219