1 .title M9312 'MM' BOOT prom for TU45/TU77/TE16 controllers 2 3 ; This source code is an exact copy of the DEC M9312 23-757A9 boot PROM. 4 ; 5 ; This boot PROM is for the TU45/TU77/TE16 MASSBUS tape controllers. 6 ; 7 ; Multiple units and/or CSR addresses are supported via different entry points. 8 ; 9 ; Standard devices are 82S131, Am27S13, 74S571 or other compatible bipolar 10 ; PROMs with a 512x4 TriState 16pin DIP architecture. This code resides in 11 ; the low half of the device; the top half is blank and unused. 12 ; 13 ; Alternatively, 82S129 compatible 256x4 TriState 16pin DIP devices can be 14 ; used, as the uppermost address line (hardwired low) is an active low chip 15 ; select (and will be correctly asserted low). 16 17 172440 tucsr =172440 ; std TU45 csrbase 18 19 000000 tucs =+0 ; control/status 20 000002 tuwc =+2 ; word count 21 000004 tuba =+4 ; bus address 22 000006 tufc =+6 ; frame count 23 000012 tuds =+12 ; drive status 24 000014 tuer =+14 ; error register 25 000016 tuas =+16 ; attention summary 26 000032 tutc =+32 ; tape control 27 28 165564 diags =165564 ; console diags phase2 entry 29 30 .asect 31 173000 .=173000 32 33 ; -------------------------------------------------- 34 35 173000 115 115 start: .ascii "MM" ; device code (reversed) 36 37 173002 000176 .word last-. ; offset to next boot header 38 39 173004 000261 mm0n: sec ; boot std csr, unit zero, no diags 40 173006 012700 000000 mm0d: mov #0,r0 ; boot std csr, unit zero, with diags 41 173012 012701 172440 mmNr: mov #tucsr,r1 ; boot std csr, unit 42 173016 010704 mmNb: mov pc,r4 ; boot csr , unit 43 173020 103064 bcc diag ; br if diags requested 44 173022 000402 br go ; return to (R4)+2 from diags 45 ; then skip over pseudo reboot vector 46 47 ; -------------------------------------------------- 48 49 173024 173000 .word 173000 ; prom start addess @ 24 50 173026 000340 .word 340 ; and priority level @ 26 51 52 ; -------------------------------------------------- 53 54 173030 000005 go: reset ; reset the world 55 56 173032 010003 mov r0,r3 ; copy unit number 57 173034 052703 001300 bis #001300,r3 ; set density 800NRZ, format 14 58 173040 010361 000032 mov r3,tutc(r1) ; execute 59 173044 032761 010000 000012 2$: bit #010000,tuds(r1) ; check medium is online 60 173052 001774 beq 2$ ; br if not yet 61 62 173054 112711 000007 movb #007,(r1) ; REWIND+GO command 63 173060 105761 000012 3$: tstb tuds(r1) ; check drive is ready 64 173064 100375 bpl 3$ ; br if not yet 65 66 173066 112711 000011 movb #011,(r1) ; DRIVE_CLEAR+GO command 67 173072 105761 000012 4$: tstb tuds(r1) ; check drive is ready 68 173076 100375 bpl 4$ ; br if not yet 69 70 173100 012761 177777 000006 mov #-1,tufc(r1) ; set frame count 71 173106 112711 000031 movb #031,(r1) ; SPACE_FORWARD+GO command 72 173112 105761 000012 5$: tstb tuds(r1) ; check drive is ready 73 173116 100375 bpl 5$ ; br if not yet 74 75 173120 016161 000016 000016 mov tuas(r1),tuas(r1) ; clear all attn summary bits 76 173126 012761 177000 000002 mov #-512.,tuwc(r1) ; set word count 77 173134 011103 mov (r1),r3 ; get current csr 78 173136 042703 000377 bic #377,r3 ; clear function code 79 173142 152703 000071 bisb #071,r3 ; READ_FORWARD+GO command 80 173146 010311 mov r3,(r1) ; execute 81 173150 105711 6$: tstb (r1) ; test ready 82 173152 100376 bpl 6$ ; loop until complete 83 84 173154 005711 tst (r1) ; test error 85 173156 100004 bpl 7$ ; br if OK 86 173160 022761 001000 000014 cmp #1000,tuer(r1) ; check only error bit is frame count 87 173166 001320 bne go ; nope, failed, back to start 88 89 173170 005007 7$: clr pc ; jmp to bootstrap location zero 90 91 ; -------------------------------------------------- 92 93 173172 000137 165564 diag: jmp @#diags ; jump to console diags 94 95 ; -------------------------------------------------- 96 97 173176 .=start+176 98 173176 162556 crc16: .word <162556> ; CRC-16 will go here 99 100 last: ; next boot prom starts here 101 102 .end 102