-- Copyright (C) 1982 by Xerox Corporation. All rights reserved.
-- File: EtherBoot.mesa, Edit: HGM February 2, 1981 11:28 PM
-- Snitched from Taft's EtherBoot.asm with a bit of help from Teco
DIRECTORY
DiskLessDefs USING [];
EtherBoot: PROGRAM EXPORTS DiskLessDefs =
BEGIN
GetPointerToBootLoader: PUBLIC PROCEDURE RETURNS [POINTER] =
BEGIN RETURN[@bootLoaderProgram]; END;
bootLoaderProgram: ARRAY [31B..426B] OF WORD ← [
-- 1
-- 2 ; EtherBoot.asm - Alto Ethernet boot loader
-- 3 ; Implemented (with much blood and sweat) by E. A. Taft / July 1976
-- 4
-- 5 ; Last modified January 2, 1978 1:54 PM
-- 6
-- 7 .ent bootLoaderPacket
-- 8 .ent EtherBoot
-- 9
-- 10 .srel
-- 11
-- 0 31B 12 bootLoaderPacket: .bootLoaderPacket
-- 1 0B 13 EtherBoot: .EtherBoot
-- 14
-- 15 .nrel
-- 16
-- 17 ; Format of an Ethernet-encapsulated Pup
-- 0 18 etherAdr = 0 ; Destination/source bytes
-- 1 19 etherType = 1 ; Ethernet type word
-- 2 20 pupLength = 2 ; Pup length
-- 3 21 pupType = 3 ; Transport control and type
-- 4 22 pupID = 4 ; Pup ID (2 words)
-- 6 23 pupDNetHost = 6 ; Pup destination net/host
-- 7 24 pupDSocket = 7 ; Pup destination socket (2 words)
-- 11 25 pupSNetHost = 11 ; Pup source net/host
-- 12 26 pupSSocket = 12 ; Pup source socket
-- 14 27 pupContents = 14 ; Pup contents start here
-- 28
-- 602 29 typeBreathOfLife = 602 ; Ethernet type for a boot loader packet
-- 1000 30 typePup = 1000 ; Ethernet type for a Pup
-- 244 31 typeMayday = 244 ; Pup type for boot file request
-- 4 32 socketMiscServices = 4 ; Socket to which request should be sent
-- 20 33 socketEFTPReceiver = 20 ; Our EFTP receiver socket
-- 34
-- 3 35 page0origin = 3 ; Where page 0 portion of loader runs
-- 624 36 page1origin = 624 ; Where page 1 portion of loader will run
-- 37
-- 38 ; Ethernet control word addresses
-- 600 39 ePLoc = 600
-- 601 40 eBLoc = 601
-- 602 41 eELoc = 602
-- 603 42 eLLoc = 603
-- 604 43 eICLoc = 604
-- 605 44 eIPLoc = 605
-- 606 45 eOCLoc = 606
-- 607 46 eOPLoc = 607
-- 610 47 eHLoc = 610
-- 48
-- 49 ; Convenient constant for accessing Ethernet control words by
-- 50 ; displacement addressing
-- 777 51 eBase = 777
-- 52
-- 53 ; EtherBoot(bfn, returnOnFail [false], host [0])
-- 54 ; BCPL-callable procedure that copies the boot loader into page 0
-- 55 ; and dives into it. bfn is the desired boot file number and
-- 56 ; host, if specified, is host from which to request the boot file
-- 57 ; (the default is zero, meaning broadcast the request).
-- 58
-- 59 ; If no boot server responds to the request and returnOnFail is true,
-- 60 ; EtherBoot returns to its caller. Pages 0 and 1 are clobbered and
-- 61 ; interrupts are disabled, so it is the caller's responsibility to
-- 62 ; save and restore these pages and reenable interrupts.
-- 63
-- 64 .EtherBoot:
-- 0 61000 65 dir ; Interrupts off
-- 1 50543 66 sta 2 bcplStack ; Save stack pointer for possible return
-- 2 40472 67 sta 0 mayday+pupID+1 ; Put bfn in mayday packet
-- 3 21400 68 lda 0 0 3 ; Get number of args
-- 4 100400 69 neg 0 0
-- 5 101405 70 inc 0 0 snr ; Skip if more than one
-- 6 405 71 jmp eb1
-- 7 175400 72 inc 3 3 ; Where to return to
-- 10 125014 73 mov# 1 1 szr ; returnOnFail true?
-- 11 54534 74 sta 3 GiveUp ; Yes, set up return pc
-- 12 101405 75 inc 0 0 snr ; Skip if more than two args
-- 13 102461 76 eb1: mkzero 0 0 skp ; No host supplied, use zero
-- 14 21003 77 lda 0 3 2 ; Host supplied, use it
-- 15 40460 78 sta 0 mayday+pupDNetHost ; Set Pup destination host
-- 16 101300 79 movs 0 0 ; Put dest in left half
-- 17 40450 80 sta 0 mayday+etherAdr ; Set Ether destination
-- 20 22406 81 lda 0 @lvBootLoaderPacket ; Get pointer to loader
-- 21 101400 82 inc 0 0 ; Compute page0image-1
-- 22 24405 83 lda 1 k400 ; Last destination address
-- 23 34405 84 lda 3 lblt ; Negative of number of words
-- 24 61005 85 blt ; Move loader into page 0
-- 25 6 86 jmp boot0-page0image+page0origin ; Dive into loader
-- 87
-- 26 0 88 lvBootLoaderPacket: bootLoaderPacket
-- 27 400 89 k400: 400
-- 30 177402 90 lblt: -401+page0origin
-- 91
-- 92 ; The Ethernet Boot Loader.
-- 93 ; The first two words are reserved for the Ethernet header.
-- 94 ; The Alto jumps to the third word of the packet after receipt.
-- 95
-- 96 .bootLoaderPacket: ; Absolute address = 1 at runtime
-- 31-- 0B, -- 97 0 ; Destination/source (filled in at runtime)
-- 32-- 602B, -- 98 typeBreathOfLife
-- 99
-- 100 ; The following code runs only in page 0 and never migrates to page 1.
-- 101 page0image: ; Absolute address = 3 at runtime
-- 102
-- 103 ; Set the parameter that determines the desired boot file
-- 33-- 22574B, -- 104 lda 0 @c177035 ; Get keyboard bits
-- 34-- 100000B, -- 105 com 0 0 ; Turn them right side up
-- 35-- 40437B,
-- 106 sta 0 mayday+pupID+1 ; Use as low 16 bits of Pup ID
-- 107
-- 108 ; Correct all memory parity by reading and writing all words in memory
-- 109 ; (note that interrupts are off, so the parity errors won't cause trouble).
-- 110 ; EtherBoot procedure enters here.
-- 36-- 102000B,
-- 111 boot0: mkminusone 0 0 ; First source adr = 0 (-1)
-- 37-- 34431B, -- 112 lda 3 k1000 ; Count = -177000
-- 40-- 164000B, -- 113 com 3 1 ; Last dest adr = 176777
-- 41-- 61005B, -- 114 blt
-- 115
-- 116 ; Zero selected regions in page 1
-- 42-- 102460B, -- 117 mkzero 0 0
-- 43-- 24567B, -- 118 lda 1 c427 ; Zero 401-427
-- 44-- 34572B, -- 119 lda 3 m27
-- 45-- 61006B, -- 120 blks
-- 46-- 24565B, -- 121 lda 1 c567 ; Zero 431-567
-- 47-- 34570B, -- 122 lda 3 m137
-- 50-- 61006B, -- 123 blks
-- 51-- 24564B, -- 124 lda 1 c777 ; Zero 600-777
-- 52-- 34566B, -- 125 lda 3 m200
-- 53-- 61006B, -- 126 blks
-- 127
-- 128 ; Copy top part of boot loader up to page 1 (note ac1 still contains 777)
-- 54-- 20565B, -- 129 lda 0 pPage1Code
-- 55-- 34565B, -- 130 lda 3 mPage1Count
-- 56-- 61005B, -- 131 blt
-- 132
-- 133 ; Set up a "Mayday" packet to broadcast
-- 57-- 125220B, -- 134 movzr 1 1 ; Make mask = 377
-- 60-- 46573B,
-- 135 sta 1 @.errcnt ; Max allowable output errors = 377
-- 61-- 20576B, -- 136 lda 0 c3 ; Reset Ethernet
-- 62-- 61004B, -- 137 sio
-- 63-- 123400B, -- 138 and 1 0 ; Mask local ethernet address
-- 64-- 30551B, -- 139 lda 2 .eBase
-- 65-- 41211B, -- 140 sta 0 eHLoc-eBase 2 ; Store for microcode
-- 66-- 4416B, -- 141 jsr boot1 ; Make pointer to output packet
-- 142
-- 143 ; The "Mayday" packet that we broadcast
-- 67-- 0B, -- 144 mayday: 0 ; Destination/source (filled in)
-- 70-- 1000B, -- 145 k1000: 1000 ; Ethernet packet type = typePup
-- 71-- 26B, -- 146 22. ; Pup length
-- 72-- 244B, -- 147 typeMayday ; Transport control/type
-- 73-- 0B, -- 148 timeout: 0 ; Pup ID
-- 74-- 0B, -- 149 0 ;
-- 75-- 0B,
-- 150 0 ; Destination net/host (broadcast or filled in)
-- 76-- 0B, -- 151 0 ; Destination socket
-- 77-- 4B, -- 152 socketMiscServices
-- 100-- 0B, -- 153 0 ; Source net/host (filled in at runtime)
-- 101-- 0B, -- 154 0 ; Source socket (EFTP receiver)
-- 102-- 20B, -- 155 socketEFTPReceiver
-- 103-- 177777B, -- 156 -1 ; Nil checksum
-- 157
-- 104-- 55210B,
-- 158 boot1: sta 3 eOPLoc-eBase 2 ; Set pointer to packet
-- 105-- 25400B, -- 159 lda 1 etherAdr 3 ; Get dest host from packet
-- 106-- 107000B, -- 160 add 0 1 ; Set source = me
-- 107-- 45400B, -- 161 sta 1 etherAdr 3
-- 110-- 41411B,
-- 162 sta 0 pupSNetHost 3 ; Set Pup source net = 0, host = me
-- 111-- 20547B, -- 163 lda 0 d13 ; Size of packet
-- 112-- 41207B, -- 164 sta 0 eOCLoc-eBase 2
-- 165
-- 166 ; Page 0 portion of boot loader (cont'd)
-- 167
-- 168 ; Loop here for each retransmission of broadcast request
-- 113-- 20544B, -- 169 boot2: lda 0 c3 ; Reset Ethernet
-- 114-- 61004B, -- 170 sio
-- 115-- 6531B, -- 171 jsr @.DoEtherOutput ; Send packet off
-- 172
-- 173 ; Set up to receive reply
-- 116-- 34517B,
-- 174 boot3: lda 3 .eBase ; For accessing Ethernet control words
-- 117-- 30544B, -- 175 lda 2 c1000 ; Where to put reply (page 2)
-- 120-- 51606B, -- 176 sta 2 eIPLoc-eBase 3
-- 121-- 20510B, -- 177 lda 0 d269 ; Max length
-- 122-- 41605B, -- 178 sta 0 eICLoc-eBase 3
-- 123-- 42526B, -- 179 sta 0 @.maxLength
-- 124-- 102460B, -- 180 mkzero 0 0 ; Zero post location
-- 125-- 41601B, -- 181 sta 0 ePLoc-eBase 3
-- 126-- 20530B, -- 182 lda 0 c2 ; etherInputCommand
-- 127-- 61004B, -- 183 sio ; Fire up receiver
-- 184
-- 185 ; Await reply
-- 130-- 21601B,
-- 186 boot4: lda 0 ePLoc-eBase 3 ; Anything happened?
-- 131-- 101014B, -- 187 sz 0 0
-- 132-- 414B, -- 188 jmp boot6 ; Yes
-- 133-- 61020B, -- 189 mul ; No, waste time
-- 134-- 14737B, -- 190 dsz timeout ; Timed out (about 1 second)?
-- 135-- 773B, -- 191 jmp boot4 ; No, keep waiting
-- 136-- 14517B, -- 192 dsz retries ; Yes, too many retries?
-- 137-- 754B, -- 193 jmp boot2 ; No, send another request
-- 140-- 20517B, -- 194 lda 0 c3 ; Yes, reset interface and give up
-- 141-- 61004B, -- 195 sio
-- 142-- 30402B, -- 196 lda 2 bcplStack
-- 143-- 2402B, -- 197 jmp @GiveUp ; Return to caller or loop
-- 198
-- 144-- 0B, -- 199 bcplStack: 0
-- 145-- 732B,
-- 200 GiveUp: Bomb-D ; Overwritten by EtherBoot if returnOnFail
-- 201
-- 202 ; Here when have possible reply
-- 146-- 34514B, -- 203 boot6: lda 3 c377 ; Good input done status?
-- 147-- 162414B, -- 204 se 3 0
-- 150-- 746B, -- 205 jmp boot3 ; No, ignore
-- 151-- 21001B, -- 206 lda 0 etherType 2 ; Yes, is it a Pup?
-- 152-- 24511B, -- 207 lda 1 c1000
-- 153-- 106414B, -- 208 se 0 1
-- 154-- 742B, -- 209 jmp boot3 ; No, ignore
-- 155-- 21003B, -- 210 lda 0 pupType 2 ; Yes, get Pup type
-- 156-- 163400B, -- 211 and 3 0
-- 157-- 35005B, -- 212 lda 3 pupID+1 2 ; Get sequence number
-- 160-- 24501B, -- 213 lda 1 c30 ; EFTP data?
-- 161-- 106415B, -- 214 sne 0 1
-- 162-- 175014B, -- 215 sz 3 3 ; Sequence number zero?
-- 163-- 733B, -- 216 jmp boot3 ; No, ignore
-- 217
-- 218 ; Page 0 portion of boot loader (cont'd)
-- 219
-- 220 ; We got a good packet, set up for transfer.
-- 164-- 21000B, -- 221 lda 0 etherAdr 2 ; Get dest/source word
-- 165-- 42465B, -- 222 sta 0 @.goodDestSource ; Save it
-- 166-- 34457B,
-- 223 lda 3 .ackPacket ; Where we will build the Ack
-- 167-- 56445B,
-- 224 sta 3 @.eOPLoc ; Set pointer (count already ok)
-- 170-- 55775B,
-- 225 sta 3 426-ackPacket+D 3 ; Cursor coordinates = (531,531)
-- 171-- 55776B, -- 226 sta 3 427-ackPacket+D 3
-- 172-- 101300B, -- 227 movs 0 0 ; Swap source and destination
-- 173-- 41400B, -- 228 sta 0 etherAdr 3 ; Store in Ack
-- 174-- 20467B, -- 229 lda 0 c1000 ; Type = Pup
-- 175-- 41401B, -- 230 sta 0 etherType 3
-- 176-- 20432B, -- 231 lda 0 d22 ; Pup length = 22
-- 177-- 41402B, -- 232 sta 0 pupLength 3
-- 200-- 121400B, -- 233 inc 1 0 ; Pup type = Ack = 31
-- 201-- 41403B, -- 234 sta 0 pupType 3
-- 202-- 21006B,
-- 235 lda 0 pupDNetHost 2 ; Copy and exchange source and
-- 203-- 41411B, -- 236 sta 0 pupSNetHost 3 ; destination ports
-- 204-- 21007B, -- 237 lda 0 pupDSocket 2
-- 205-- 41412B, -- 238 sta 0 pupSSocket 3
-- 206-- 21010B, -- 239 lda 0 pupDSocket+1 2
-- 207-- 41413B, -- 240 sta 0 pupSSocket+1 3
-- 210-- 21011B, -- 241 lda 0 pupSNetHost 2
-- 211-- 41406B, -- 242 sta 0 pupDNetHost 3
-- 212-- 21012B, -- 243 lda 0 pupSSocket 2
-- 213-- 41407B, -- 244 sta 0 pupDSocket 3
-- 214-- 21013B, -- 245 lda 0 pupSSocket+1 2
-- 215-- 41410B, -- 246 sta 0 pupDSocket+1 3
-- 216-- 15414B, -- 247 dsz pupContents 3 ; Pup checksum = nil (-1)
-- 248
-- 249 ; Now read and discard packet 0 (which has the disk boot loader)
-- 250 ; and read packet 1, which contains the data destined for page 0.
-- 217-- 6427B,
-- 251 jsr @.DoEtherOutput ; Ack the packet we just got
-- 220-- 12434B, -- 252 isz @.seqNum ; Advance to sequence number 1
-- 221-- 6426B, -- 253 jsr @.ReceiveEFTPPacket ; Read packet 1
-- 254
-- 255 ; Set up to transfer packet data into page 0 and jump to remaining
-- 256 ; boot code in page 1
-- 222-- 20421B, -- 257 lda 0 pPage2Data ; First source adr -1
-- 223-- 24437B, -- 258 lda 1 c377 ; Last dest adr
-- 224-- 134000B, -- 259 com 1 3 ; - number of words (400)
-- 225-- 30417B,
-- 260 lda 2 pPage2Packet ; Where to start reading packet 2
-- 226-- 2422B, -- 261 jmp @.ContinueBoot ; Jump to code in page 1
-- 262
-- 263
-- 227-- 177035B, -- 264 c177035: 177035
-- 230-- 26B, -- 265 d22: 22.
-- 231-- 415B, -- 266 d269: 269.
-- 232-- 427B, -- 267 c427: 427
-- 233-- 567B, -- 268 c567: 567
-- 234-- 607B, -- 269 .eOPLoc: eOPLoc
-- 270 .eBase:
-- 235-- 777B, -- 271 c777: 777
-- 236-- 177751B, -- 272 m27: -27
-- 237-- 177641B, -- 273 m137: -137
-- 240-- 177600B, -- 274 m200: -200
-- 241-- 225B, -- 275 pPage1Code: page1image-page0image+page0origin-1
-- 242-- 177624B, -- 276 mPage1Count: page1origin-1000
-- 243-- 1013B,
-- 277 pPage2Data: 1000+12.-1 ; Where page 0 data sits when in page 2
-- 244-- 764B,
-- 278 pPage2Packet: 1000-12. ; Where to start reading packet 2
-- 245-- 431B,
-- 279 .ackPacket: ackPacket-D ; Where Ack packet is built
-- 246-- 712B, -- 280 .DoEtherOutput: DoEtherOutput-D
-- 247-- 634B, -- 281 .ReceiveEFTPPacket: ReceiveEFTPPacket-D
-- 250-- 735B, -- 282 .ContinueBoot: ContinueBoot-D
-- 251-- 611B, -- 283 .maxLength: maxLength-D
-- 252-- 567B, -- 284 .goodDestSource: goodDestSource-D
-- 253-- 564B, -- 285 .errcnt: errcnt-D
-- 254-- 566B, -- 286 .seqNum: seqNum-D
-- 255-- 36B, -- 287 retries: 30. ; Max number of broadcast retries
-- 288
-- 289 ; Page 1 portion of boot program
-- 290
-- 291 page1image:
-- 292
-- 293
-- 294 ; Assemble variables and constants here so they can be reached
-- 295 ; from the page 0 code also.
-- 296
-- 297
-- 298 ; Constants
-- 256-- 2B, -- 299 c2: 2
-- 257-- 3B, -- 300 c3: 3
-- 260-- 15B, -- 301 d13: 13.
-- 261-- 30B, -- 302 c30: 30 ; typeEFTPData
-- 262-- 377B, -- 303 c377: 377
-- 263-- 1000B, -- 304 c1000: 1000
-- 264-- 177764B, -- 305 md12: -12.
-- 306
-- 177432 307 D = page1image-page1origin ; Load - runtime displacement
-- 308 ; Note -
-- 309 ; To generate a page 1 pc-relative address for absolute address "X"
-- 310 ; write "X+D".
-- 311 ; To generate an absolute (runtime) page 1 address for label "X"
-- 312 ; write "X-D".
-- 313
-- 314 ; Ethernet control words addresses, for referencing relative
-- 315 ; to the page 1 portion of the boot loader.
-- 232 316 rEPLoc = ePLoc+D
-- 233 317 rEBLoc = eBLoc+D
-- 234 318 rEELoc = eELoc+D
-- 235 319 rELLoc = eLLoc+D
-- 236 320 rEICLoc = eICLoc+D
-- 237 321 rEIPLoc = eIPLoc+D
-- 240 322 rEOCLoc = eOCLoc+D
-- 241 323 rEOPLoc = eOPLoc+D
-- 242 324 rEHLoc = eHLoc+D
-- 325
-- 326 ; Random page 1 words we use as temporaries.
-- 327 ; All are assumed to be initialized to zero.
-- 328
-- 329 ; 400-414 are used for scratch
-- 330
-- 63 331 ackPacket = 431+D ; 13. words in which Ack packet is built.
-- 332 ; This is the cursor bitmap!
-- 216 333 errcnt = 564+D ; Output error countdown
-- 217 334 recret = 565+D ; Return from ReceiveEFTPPacket
-- 220 335 seqNum = 566+D ; Current EFTP sequence number
-- 221 336 goodDestSource = 567+D ; Ethernet address of me/partner
-- 243 337 maxLength = 611+D ; Max input packet length (269 or 12)
-- 244 338 dallyTimeout = 612+D ; Timeout for end dally if nonzero
-- 245 339 endFlag = 613+D ; Zero if packet was Data, nonzero if End
-- 340
-- 341
-- 265-- 436B,
-- 342 .ackID1: ackPacket-D+pupID+1 ; Pointer to Ack's sequence number
-- 343
-- 344 ; Page 1 portion of boot loader (cont'd)
-- 345 ; Subroutines called from both page 0 and page 1
-- 346
-- 347 ; Receive EFTP packet
-- 348 ; 2/ where to put it in memory
-- 349 ; Ac2 is unchanged upon return.
-- 350 ; endFlag will be zero if a Data was received, nonzero if End.
-- 351 ; If dallyTimeout is nonzero, it will be counted down and the
-- 352 ; routine will return if it reaches zero.
-- 353
-- 354 ReceiveEFTPPacket:
-- 266-- 54731B, -- 355 sta 3 recret ; Save return
-- 267-- 50750B, -- 356 sta 2 rEIPLoc ; Set input pointer
-- 357
-- 358 ; Await a new packet
-- 270-- 20753B, -- 359 rec1: lda 0 maxLength ; Set count
-- 271-- 40745B, -- 360 sta 0 rEICLoc
-- 272-- 102460B, -- 361 mkzero 0 0 ; Zero post location
-- 273-- 40737B, -- 362 sta 0 rEPLoc
-- 274-- 20762B, -- 363 lda 0 c2 ; etherInputCommand = 2
-- 275-- 61004B, -- 364 sio ; Fire up receiver
-- 276-- 20734B,
-- 365 rec1a: lda 0 rEPLoc ; Wait for something to happen
-- 277-- 105304B, -- 366 movs 0 1 szr
-- 300-- 406B, -- 367 jmp rec1b ; Something happened, check it
-- 301-- 20743B,
-- 368 lda 0 dallyTimeout ; No activity yet, check timeout
-- 302-- 101014B, -- 369 sz 0 0
-- 303-- 14741B,
-- 370 dsz dallyTimeout ; One is set, count it down
-- 304-- 772B, -- 371 jmp rec1a ; Not set or not yet timed out
-- 305-- 2712B, -- 372 jmp @recret ; Timed out, return now
-- 373
-- 374 ; A packet has arrived. Accept if good input or buffer overrun.
-- 375 ; This code is a bit mysterious because the way it works is to
-- 376 ; set ac1 = 1000 iff the status is acceptable. This then gets
-- 377 ; compared with the incoming Ethernet type which should be 1000.
-- 306-- 34754B, -- 378 rec1b: lda 3 c377
-- 307-- 167700B, -- 379 ands 3 1 ; Ac1 ← 1000 iff post code = 2
-- 310-- 116415B, -- 380 sne 0 3 ; Good normal input done status?
-- 311-- 24752B,
-- 381 lda 1 c1000 ; Yes, make it look like post 2
-- 382
-- 383 ; Ensure that it is an EFTP Data or End from the correct partner
-- 312-- 21001B, -- 384 lda 0 etherType 2 ; Get ethernet type word
-- 313-- 106414B, -- 385 se 0 1 ; Is it a Pup? (1000)
-- 314-- 754B, -- 386 jmp rec1 ; No, ignore
-- 315-- 21000B,
-- 387 lda 0 etherAdr 2 ; Get destination/source word
-- 316-- 24703B, -- 388 lda 1 goodDestSource ; Correct partner?
-- 317-- 106414B, -- 389 se 0 1
-- 320-- 750B, -- 390 jmp rec1 ; No, ignore (should really abort)
-- 321-- 21003B, -- 391 lda 0 pupType 2 ; Get Pup type
-- 322-- 163400B, -- 392 and 3 0
-- 323-- 24736B, -- 393 lda 1 c30 ; Switch on it
-- 324-- 106405B, -- 394 sub 0 1 snr
-- 325-- 404B, -- 395 jmp rec3 ; Got Data packet
-- 326-- 121400B, -- 396 inc 1 0
-- 327-- 101404B, -- 397 inc 0 0 szr ; Skip if End
-- 330-- 740B, -- 398 jmp rec1 ; Neither Data nor End, ignore
-- 331-- 44714B,
-- 399 rec3: sta 1 endFlag ; Set nonzero if this is an End
-- 400
-- 401 ; Got an EFTP Data or end packet.
-- 402 ; Now check sequence number and send Ack
-- 332-- 21005B,
-- 403 lda 0 pupID+1 2 ; Get packet sequence number
-- 333-- 42732B, -- 404 sta 0 @.ackID1 ; Set it for possible Ack
-- 334-- 24664B, -- 405 lda 1 seqNum ; Get expected sequence number
-- 335-- 122405B, -- 406 sub 1 0 snr ; Is it the right one?
-- 336-- 404B, -- 407 jmp rec4 ; Yes
-- 337-- 101405B,
-- 408 inc 0 0 snr ; No, retransmission of last one?
-- 340-- 4404B, -- 409 jsr DoEtherOutput ; Yes, ack it
-- 341-- 727B, -- 410 jmp rec1 ; Ignore it and look for next
-- 411
-- 412 ; Here when got a new packet
-- 342-- 10656B, -- 413 rec4: isz seqNum ; Advance sequence number
-- 343-- 34654B, -- 414 lda 3 recret ; Restore return pc
-- 415 ; Fall into DoEtherOutput
-- 416
-- 417 ; Page 1 portion of boot loader (cont'd)
-- 418
-- 419 ; Do Ethernet output
-- 420 ; Assumes the packet and eOPLoc and eOCLoc are set up
-- 421 ; Does not clobber ac2
-- 422
-- 423 DoEtherOutput:
-- 344-- 24403B, -- 424 lda 1 k777
-- 345-- 120500B, -- 425 negl 1 0 ; Delay about 2 ms to ensure that
-- 346-- 101404B, -- 426 inc 0 0 szr ; our ack is heard
-- 347-- 777B, -- 427 k777: 777 ; (Otherwise known as "jmp .-1")
-- 350-- 40662B, -- 428 sta 0 rEPLoc ; Zero post location
-- 351-- 40664B, -- 429 sta 0 rELLoc ; Zero load location
-- 352-- 40664B, -- 430 sta 0 rEICLoc ; Zero input count location
-- 353-- 102520B, -- 431 mkone 0 0 ; etherOutputCommand = 1
-- 354-- 61004B, -- 432 sio ; Start output
-- 355-- 20655B, -- 433 lda 0 rEPLoc ; Wait for something to happen
-- 356-- 101015B, -- 434 snz 0 0
-- 357-- 776B, -- 435 jmp .-2
-- 360-- 106415B, -- 436 sne 0 1 ; Good output done? ( = 777)
-- 361-- 1400B, -- 437 jmp 0 3 ; Yes, done, return
-- 362-- 14634B, -- 438 dsz errcnt ; No, check error counter
-- 363-- 761B, -- 439 jmp DoEtherOutput ; Retry
-- 440
-- 441 ; If we get too many errors, probably the Ethernet interface
-- 442 ; is broken, so we should reset and give up lest we pollute
-- 443 ; the Ethernet indefinitely
-- 364-- 20673B, -- 444 Bomb: lda 0 c3 ; etherResetCommand
-- 365-- 61004B, -- 445 sio
-- 366-- 400B, -- 446 c400: 400 ; (Otherwise known as "jmp .")
-- 447
-- 448 ; ** Main page 1 program **
-- 449 ; Control resumes here when the page 0 code is finished.
-- 450 ; When we get here, the second data packet of the transfer has
-- 451 ; been received (the one destined for page 0) and now resides
-- 452 ; in page 2, and the ac's are set up such that blt will move
-- 453 ; the data to page 0. This code's responsibility is to receive
-- 454 ; the remaining pages of the transfer and store them starting at
-- 455 ; page 2. The following variables are already set up:
-- 456 ; goodDestSource expected Ethernet dest/source word
-- 457 ; seqNum the next expected EFTP sequence number (2)
-- 458 ; ac2 points to place to store next packet
-- 459 ; (1000 minus the offset pupContents)
-- 460 ; Also, an Ack packet has already been built at ackPacket.
-- 461
-- 462 ContinueBoot:
-- 367-- 61005B, -- 463 blt ; Copy data to page 0
-- 464
-- 465 ; The main loop of the EFTP boot load sequence.
-- 466 ; First, save away the stuff at the end of the previous page
-- 467 ; that will get clobbered by the new Pup's header.
-- 468 ; Locations 400-413 are used for scratch.
-- 370-- 102000B,
-- 469 bootlp: mkminusone 0 0 ; Compute first source adr -1
-- 371-- 143000B, -- 470 add 2 0
-- 372-- 34672B, -- 471 lda 3 md12 ; -12. (number of words)
-- 373-- 24667B,
-- 472 lda 1 c377 ; Compute pointer to last word of
-- 374-- 166400B, -- 473 sub 3 1 ; save area
-- 375-- 61005B, -- 474 blt ; Save the data
-- 475
-- 476 ; Now receive the next Data (or End) packet
-- 376-- 4670B, -- 477 jsr ReceiveEFTPPacket
-- 478
-- 479 ; Now restore the clobbered region
-- 377-- 20663B,
-- 480 lda 0 c377 ; Pointer to start of save area -1
-- 400-- 34664B, -- 481 lda 3 md12 ; -12. (number of words)
-- 401-- 164000B, -- 482 com 3 1 ; Compute pointer to last word of
-- 402-- 147000B, -- 483 add 2 1 ; clobbered region
-- 403-- 61005B, -- 484 blt ; Move the data back
-- 485
-- 486 ; Unless memory is now full, advance the pointer and repeat.
-- 487 ; If we just read into the last page of memory, set the pointer to
-- 488 ; a scratch region at 400 and set the count so that only a minimum-
-- 489 ; length Pup (e.g., the End that we are expecting) will be
-- 490 ; accepted.
-- 404-- 24762B, -- 491 lda 1 c400 ; Amount to advance pointer by
-- 405-- 132414B,
-- 492 se 1 2 ; Skip if already at scratch region
-- 406-- 133000B, -- 493 add 1 2 ; Normally, advance pointer
-- 407-- 20636B, -- 494 lda 0 endFlag
-- 410-- 34416B, -- 495 lda 3 memOverflow
-- 411-- 101015B, -- 496 snz 0 0 ; Was an End received?
-- 412-- 156415B, -- 497 sne 2 3 ; Or beyond end of memory?
-- 413-- 131001B, -- 498 mov 1 2 skp ; Yes, set pointer to 400
-- 414-- 754B, -- 499 jmp bootlp ; No, continue normally
-- 415-- 24643B, -- 500 lda 1 d13 ; Limit packet length to minimum
-- 416-- 44625B, -- 501 sta 1 maxLength
-- 417-- 101015B, -- 502 snz 0 0 ; Received End?
-- 420-- 750B, -- 503 jmp bootlp ; No, continue
-- 421-- 14623B,
-- 504 dsz dallyTimeout ; Yes, enable timeout (set to -1)
-- 422-- 4644B,
-- 505 jsr ReceiveEFTPPacket ; Await second End or timeout
-- 423-- 20634B, -- 506 lda 0 c3 ; Reset the Ethernet
-- 424-- 61004B, -- 507 sio
-- 425-- 2000B, -- 508 jmp @0 ; Jump into the bootload!
-- 509
-- 426-- 176764B
-- 510 memOverflow: 177000-12. ; Where ac2 will point when memory is full
-- 511
-- 512
-- 513 ; ** Warning **
-- 514 ; The last 12 words of page 1 get clobbered during the act of
-- 515 ; receiving page 2. This is ok since those 12 words are saved
-- 516 ; and restored. However, the stuff in those words must not be
-- 517 ; executed or referenced while in the clobbered state!
-- 518
-- 519 .end
];
END..