1 /* htboot.c 6.1 83/07/29 */ 2 3 /* 4 * VAX tape boot block for distribution tapes 5 * works on massbus tu10/te16/tu45/tu77 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 .set RELOC,0x70000 12 /* a.out defines */ 13 .set HDRSIZ,040 /* size of file header for VAX */ 14 .set MAGIC,0410 /* file type id in header */ 15 .set TSIZ,4 /* text size */ 16 .set DSIZ,8 /* data size */ 17 .set BSIZ,12 /* bss size */ 18 .set TENT,024 /* task header entry loc */ 19 /* tp directory definitions */ 20 .set FILSIZ,38 /* tp direc offset for file size */ 21 .set BNUM,44 /* tp dir offset for start block no. */ 22 .set ENTSIZ,64 /* size of 1 TP dir entry, bytes */ 23 .set PTHSIZ,32 /* size of TP path name, bytes */ 24 .set BLKSIZ,512 /* tape block size, bytes */ 25 .set NUMDIR,24 /* no. of dir blocks on tape */ 26 .set ENTBLK,8 /* no. of dir entries per tape block */ 27 /* processor registers and bits */ 28 .set RXCS,32 29 .set RXDB,33 30 .set TXCS,34 31 .set TXDB,35 32 .set RXCS_DONE,0x80 33 .set TXCS_RDY,0x80 34 .set TXCS_pr,7 /* bit position of TXCS ready bit */ 35 .set RXCS_pd,7 /* bit position of RXCS done bit */ 36 /* MBA registers */ 37 .set MBA_CSR,0 /* configuration and status register */ 38 .set MBA_CR,4 /* MBA control reg */ 39 .set MBA_SR,8 /* MBA status reg */ 40 .set MBA_VAR,12 /* MBA virt addr reg */ 41 .set MBA_BCR,16 /* MBA byte count reg */ 42 .set MBA_MAP,0x800 /* start of MBA map reg's */ 43 .set MRV,0x80000000 44 /* TE16/TU45/TU77 mba registers */ 45 .set HTCS1,0 /* HT control 1 reg */ 46 .set HTDS,4 /* status reg */ 47 .set HTER,8 /* error reg */ 48 .set HTAS,16 /* attention summary */ 49 .set HTFC,20 /* frame count */ 50 .set HTTC,36 /* HT tape control */ 51 /* HT commands */ 52 .set GO,1 /* GO bit */ 53 .set HT_REW,6 /* rewind, on-line */ 54 .set HT_DCLR,010 /* drive clear */ 55 .set HT_SREV,032 /* space reverse */ 56 .set HT_RCOM,070 /* read forward */ 57 /* HT bits */ 58 .set ERR,040000 /* composite error bit in status reg */ 59 .set TCHAR,012300 /* unit 0, odd parity, PDP11, 1600 BPI NRZ, */ 60 /* abort on error - for tape controller */ 61 .set DRDY,0200 /* HT/drive ready in status reg */ 62 .set HT_pd,7 /* bit position of HT DRDY bit */ 63 .set HT_pe,14 /* bit position of HT ERROR bit */ 64 /* local stack variables */ 65 .set tapa,-4 /* desired tape addr */ 66 .set mtapa,-8 /* current tape addr */ 67 .set name,-8-PTHSIZ /* operator-typed file name */ 68 /* register usage */ 69 .set rMBA,r10 70 .set rHT,r11 71 72 /* initialization */ 73 init: 74 mull2 $0x80,%rHT 75 addl2 $0x400,%rHT 76 addl2 %rMBA,%rHT 77 movl $RELOC,fp /* core loc to which to move this program */ 78 addl3 $name,fp,sp /* set stack pointer, leaving room for locals */ 79 clrl r0 80 1: 81 movc3 $end,(r0),(fp) /* move boot up to relocated position */ 82 jmp start+RELOC 83 start: 84 movl $1,MBA_CR(%rMBA) /* MBA init */ 85 movl $TCHAR,HTTC(%rHT) /* drive no., etc. */ 86 movl $HT_DCLR+GO,HTCS1(%rHT) /* drive clear */ 87 bsbw rew /* rewind input tape */ 88 movab name(fp),r4 /* start of filename storage */ 89 movzbl $'=,r0 /* prompt character */ 90 bsbw putc /* output char to main console */ 91 /* read in a file name */ 92 movl r4,r1 /* loc at which to store file name */ 93 nxtc: 94 bsbw getc /* get input char's in file name */ 95 cmpb r0,$012 /* terminator ? */ 96 beql nullc 97 movb r0,(r1)+ 98 brb nxtc 99 nullc: 100 subl3 r4,r1,r9 /* size of path name */ 101 beql start /* dumb operator */ 102 clrb (r1)+ 103 incl r9 104 /* user-specified TP filename has been stored at name(fp) */ 105 /* read in entire tp directory contents into low core */ 106 dirred: 107 movl $8,tapa(fp) /* tp directory starts at block 8 */ 108 movl $(NUMDIR*BLKSIZ),r6 /* no. bytes in total dir */ 109 bsbw taper /* read no. bytes indicated */ 110 /* search entire directory for user-specified file name */ 111 clrl r5 /* dir buff loc = 0 */ 112 nxtdir: 113 cmpc3 r9,(r5),(r4) /* see if dir entry matches filename */ 114 beql fndfil /* found match */ 115 acbl $NUMDIR*BLKSIZ-1,$ENTSIZ,r5,nxtdir 116 /* see if done with tp dir */ 117 brw start /* entry not in directory; start over */ 118 /* found desired tp dir entry */ 119 fndfil: 120 movzwl BNUM(r5),tapa(fp) /* start block no., 2 bytes */ 121 addl2 $7,tapa(fp) /* skip 7 boot blocks */ 122 movzwl FILSIZ(r5),r6 /* low 2 bytes file size */ 123 insv FILSIZ-1(r5),$16,$8,r6 /* file size, high byte */ 124 cmpl r6,$RELOC-512 /* check if file fits below stack */ 125 blss filok /* file o.k. */ 126 brw start /* file too large */ 127 /* time to read in desired file from tape */ 128 filok: 129 movl r6,r7 /* save r6 */ 130 bsbb taper 131 bsbw rew 132 /* clear core */ 133 subl3 r7,$RELOC-4,r0 /* no. bytes to clear */ 134 1: 135 clrb (r7)+ 136 sobgtr r0,1b 137 /* time to jump to start of file & execute */ 138 addl3 $20,fp,ap 139 clrl r5 140 calls $0,(r5) 141 brw start 142 /* taper: movcTAPE (r6),tapa(fp),0 */ 143 rew2: 144 bsbb rew /* beginning of tape */ 145 taper0: 146 bsbb rrec /* advance 1 block; never want blk0 */ 147 taper: 148 clrl r0 /* page no. */ 149 cmpl mtapa(fp),tapa(fp) /* current position .vs. desired */ 150 bgtr rew2 151 blss taper0 152 1: 153 bsbb rrec 154 acbl $1,$-BLKSIZ,r6,1b 155 rsb 156 /* rew: rewind the tape */ 157 rew: 158 clrl mtapa(fp) /* current position */ 159 movl $HT_REW+GO,HTCS1(%rHT) /* rewind */ 160 rsb 161 /* rrec: read 1 block from mag tape into page (r0) */ 162 rrec: 163 /* pushl r0; movzbl $'r,r0; bsbw putc; movl (sp)+,r0; */ 164 movl HTDS(%rHT),r2 165 bbc $HT_pd,r2,rrec /* HT & drive ready ? */ 166 movl $-BLKSIZ,MBA_BCR(%rMBA) 167 bisl3 $MRV,r0,MBA_MAP(%rMBA) 168 clrl MBA_VAR(%rMBA) 169 movl $HT_RCOM+GO,HTCS1(%rHT) /* read forward */ 170 1: 171 movl HTDS(%rHT),r2 172 bbc $HT_pd,r2,1b 173 movl HTER(%rHT),r2 174 bbc $HT_pe,r2,2f /* any read errors ? */ 175 clrl HTDS(%rHT) /* clear status - try to recover */ 176 mnegl $1,HTFC(%rHT) /* frame count for backspace */ 177 movl $HT_SREV+GO,HTCS1(%rHT) /* space reverse */ 178 brb rrec 179 2: 180 incl r0 /* next page no. */ 181 incl mtapa(fp) /* mag tape block position */ 182 rsb 183 getc: 184 mfpr $RXCS,r0 185 bbc $RXCS_pd,r0,getc /* receiver ready ? */ 186 mfpr $RXDB,r0 187 extzv $0,$7,r0,r0 188 cmpb r0,$015 189 bneq putc 190 bsbb putc 191 movb $0,r0 192 bsbb putc 193 movb $012,r0 194 putc: 195 mfpr $TXCS,r2 196 bbc $TXCS_pr,r2,putc /* transmitter ready ? */ 197 extzv $0,$7,r0,r0 198 mtpr r0,$TXDB 199 rsb 200 end: 201