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Text File | 1991-02-26 | 8.1 KB | 324 lines

MODE 7 *TAPE PAGE = &E00 REM REM BBC end of !BBCTape application REM REM (C) S. Burke, 26/2/91 REM REM The next few lines define where the buffers are, where the REM code goes and where the file loads to. REM : name = &0B00 name_high = &0B name_low = &00 block = &0B10 block_high = &0B block_low = &10 code_start = &0B30 load_page = &0E : osfind = &FFCE osbget = &FFD7 osfile = &FFDD :REM Page 335 of the Advanced User Guide is wrong! osbyte = &FFF4 : FOR opt%=0 TO 3 STEP 3 P% = code_start [OPT opt% .go LDX #0 LDA #2 JSR osbyte \ disable RS423 LDX #0 LDA #15 JSR osbyte \ flush all buffers LDX #2 TXA JSR osbyte \ enable RS423 receive .mainloop LDA #&0D STA name \ null name JSR handshake : JSR get \ get command CPY #&C0 BEQ end \ quit : CPY #&30 BNE load JSR put_ok \ confirm command JSR get_name \ get filename JSR handshake JSR get .load CPY #&0C BNE load_byte JSR put_ok \ confirm command JSR load_file JSR send_file JMP mainloop .load_byte CPY #&03 BNE command_error JSR put_ok \ confirm command JSR load_bget JSR send_file JMP mainloop .command_error LDA #0 JSR put \ command error JMP mainloop .end RTS .load_file LDA #name_low \ set up parameter block STA block LDA #name_high STA block+1 LDA #0 STA block+2 STA block+6 LDA #load_page STA block+3 LDA #&FF STA block+4 STA block+5 LDX #block_low LDY #block_high JSR osfile \ load file LDA block+10 STA &71 LDA block+11 STA &72 \ put file length in &71, &72 JSR read_load_exec JMP read_name \ get load/exec address and name .load_bget LDA #0 STA &71:STA &72 \ file length in &71, &72 STA &73 LDA #load_page STA &74 \ load address in &73, &74 : LDX #name_low LDY #name_high LDA #&40 JSR osfind \ open file CMP #0 BEQ end \ open failed? STA &70 \ file handle LDY #0 .loop JSR escape \ check for escape TYA:TAX \ no TYX instruction! LDY &70 JSR osbget \ get byte PHA:TXA:TAY:PLA \ just TXY! BCS eof \ end of file? STA (&73),Y \ can't use X register INY BNE loop \ done 256 bytes? INC &72:INC &74 \ increment high bytes of counters BPL loop \ should always be taken .eof STY &71:STY &73 \ set low bytes of counters JSR read_load_exec JSR read_name \ get load/exec address and name LDY &70 LDA #0 JMP osfind \ close file .read_name LDX #&FF .nameloop INX CPX #&C BEQ too_far LDA &3B2,X \ pull filename out of cassette workspace STA name,X \ see AUG p. 279 BNE nameloop .too_far LDA #&0D STA name,X RTS .get_name LDX #&FF STX &81 \ "get" corrupts registers .get_char CPX #&B BEQ too_far JSR get \ get filename from Arc TYA INC &81 LDX &81 STA name,X CMP #&0D BNE get_char RTS .read_load_exec LDX #8 .load_exec_loop LDA &3BD,X \ load/exec address from cassette workspace STA &81,X DEX BNE load_exec_loop RTS .handshake LDA #ASC("S") JSR put LDA #ASC("B") JSR put \ send "SB" ... JSR get CPY #ASC("s") BNE handshake JSR get CPY #ASC("b") BNE handshake \ ... and receive "sb" to handshake RTS .send_file LDA &71 JSR put LDA &72 JSR put \ send file length : LDA #load_page STA &74 LDA #0 STA &73 \ reset load address DEC &72 \ need this for test below BMI last_block \ file length < 256 bytes? STA &80 \ block length = 0 ( = 256) .send_block JSR put_ok \ not eof LDA #3 \ send length 3 times STA &76 \ use CRC low byte as counter .lenout LDA &80 JSR put \ output block length DEC &76 BNE lenout \ CRC low byte zero at exit LDY #0 STY &75 \ initialise CRC high byte .send_byte STY &70 \ save offset LDA (&73),Y \ load next byte ... PHA JSR put PLA \ get character back JSR crc \ update crc LDY &70 INY \ increment offset CPY &80 BNE send_byte \ end of block? : LDA &75 JSR put \ output CRC high byte LDA &76 JSR put \ output CRC low byte : JSR get \ look for confirmation TYA BEQ send_block \ zero means error, so do again : INC &74 \ increment address high byte DEC &72 \ decrement length high byte BPL send_block \ are we finished? .last_block LDY #0 LDA &71 \ length of last block STY &71 \ set length to zero STA &80 BNE send_block \ output if non-zero LDA #0 JSR put \ zero marks eof JSR put_load_exec \ send the load/exec adress .put_name \ fall through to put_name ... LDX #&FF STX &81 \ "put" corrupts registers .put_char \ output file name INC &81 LDX &81 LDA name,X PHA JSR put PLA CMP #&0D BNE put_char RTS .put_load_exec \ put out load/exec address LDX #0 STX &81 \ "put" corrupts registers .put_load_exec_loop LDA &82,X JSR put INC &81 LDX &81 CPX #8 BNE put_load_exec_loop RTS .put_ok LDA #&FF .put PHA \ save value to output JSR escape LDX #&FD LDA #&80 JSR osbyte \ get # empty bytes in RS423 output buffer CPX #9 PLA BCC put \ if < 9 bytes remain, wait ... : LDX #2 TAY LDA #&8A JMP osbyte \ ... and send it .get JSR escape LDX #1 LDA #&91 JSR osbyte \ read a byte BCS get RTS .crc EOR &75 \ calculate CRC in &75, &76 STA &75 \ algorithm from Advanced User Guide LDX #8 \ I hope it's right! .crc_loop LDA &75 ROL A BCC b7z LDA &75 EOR #8 STA &75 LDA &76 EOR #&10 STA &76 .b7z ROL &76 ROL &75 DEX BNE crc_loop RTS .escape LDA &FF BMI error RTS .error LDA #&7E JSR osbyte \ acknowledge escape LDX #0 LDA #&0F JSR osbyte \ flush buffers (just in case) LDY #0 LDA #0 JSR &FFCE \ close all files BRK ] ?P% = &11 P% = P% + 1 $P% = "Escape" + CHR$0 NEXT opt% *OPT 1,2 RUN CALL go