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!6502Em/Docs/VirtualDFS
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Zipped Apps » 6502em |
| Filename: | !6502Em/Docs/VirtualDFS |
| Read OK: | ✔ |
| File size: | 0CF3 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
6502Em: The Filing System ========================= The emulator provides a full filing system by means of the VDFS ROM. The following commands can be used to select the Virtual DFS ROM as the current filing system: *DISC *DISC *ADFS *FADFS In addition, the following commands are offered: *Quit (Return to the desktop) *Desktop (Return to the desktop) *Shadow (dummy command) *SRLoad (load image into sideways RAM) *SRWrite (copy memory into sideways RAM) ImageDFS and 6502Em ------------------- ImageDFS is available from WSS. Partial emulation of OSWORD &72 and &7F is performed by 6502Em. A much fuller implementation of OSWORD &7F is offered by ImageDFS. Even if ImageDFS is not loaded, *DRIVE assumes that you are running from a DFS disc that has been copied to ADFS. So for example *DRIVE 2 will attempt to change to the directory 'DFSSide2'. However if ImageDFS is loaded, *DRIVE <n> will change directory to access a physical floppy drive unless a DFSImage has been dropped onto 6502Em's icon, in which case it will behave as above. To access a physical floppy drive if ImageDFS is now loaded, *Mount <n> should be used. Changing Directory ------------------ The DFS filing system structure is fully emulated by noticing when an ADFS directory's name is one letter long. eg if your Currently Selected Directory (CSD) is ADFS::HD.$.BBC.Games.J then: *DIR K will attempt to set the CSD to ADFS::HD.$.BBC.Games.K *DIR J will leave the CSD unaltered *DIR $ will set the CSD to ADFS::HD.$.BBC.Games (to change to the "real" root directory, use *DIR :4.$) *DIR ^ will set the CSD to ADFS::HD.$.BBC.Games eg if your CSD is ADFS::HD.$.BBC.Games then: *DIR $ will leave the CSD unchanged *DIR ^ will set the CSD to ADFS::HD.$.BBC ************************************************************* * If your CSD is set to ADFS::HD.$.BBC.G.L then ambiguity * * can arise, so single letter directories should NOT be * * used within each other. * ************************************************************* Drive numbers within filenames (eg :0.E.Jameson) are ignored so that you can save positions of games onto your hard disc. To specify a drive, use ADFS::0.Jameson *Mount is ignored To change drive use *DIR :0, *DIR ADFS::0, *DIR ADFS::HD etc RISC OS's CSD is not changed by the emulator, allowing several incarnations of the emulator to be active. Some filing systems (eg DOSFS) do not support OSGBPB 8, so programs that use it will not work on such filing systems. OSFSC, OSFIND, OSGBPB, OSBPUT, OSBGET, OSARGS, OSFILE are all fully supported. In addition, OSGBPB 9 is partially supported (for the current directory): block?0=number of files to read (number of files read) block!1=address in memory of data block!5=length of data block block!9=sequential pointer (0 for first call, -1 when finished) RISC OS errors are passed back into the emulator via BRK. Filing system operations appear instantaneous to the emulator (ie do not run filing system benchmarks within the emulator!) Although the operating system normally appears to be ROM, it can be overwritten by filing system calls (eg *Load) Files that will extend beyond &FFFF will generate an error if you try to load them. (normally files might wrap round back to &0000)
00000000 36 35 30 32 45 6d 3a 20 54 68 65 20 46 69 6c 69 |6502Em: The Fili| 00000010 6e 67 20 53 79 73 74 65 6d 0a 3d 3d 3d 3d 3d 3d |ng System.======| 00000020 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000030 3d 3d 3d 0a 0a 54 68 65 20 65 6d 75 6c 61 74 6f |===..The emulato| 00000040 72 20 70 72 6f 76 69 64 65 73 20 61 20 66 75 6c |r provides a ful| 00000050 6c 20 66 69 6c 69 6e 67 20 73 79 73 74 65 6d 20 |l filing system | 00000060 62 79 20 6d 65 61 6e 73 20 6f 66 20 74 68 65 0a |by means of the.| 00000070 56 44 46 53 20 52 4f 4d 2e 0a 54 68 65 20 66 6f |VDFS ROM..The fo| 00000080 6c 6c 6f 77 69 6e 67 20 63 6f 6d 6d 61 6e 64 73 |llowing commands| 00000090 20 63 61 6e 20 62 65 20 75 73 65 64 20 74 6f 20 | can be used to | 000000a0 73 65 6c 65 63 74 20 74 68 65 20 56 69 72 74 75 |select the Virtu| 000000b0 61 6c 20 44 46 53 0a 52 4f 4d 20 61 73 20 74 68 |al DFS.ROM as th| 000000c0 65 20 63 75 72 72 65 6e 74 20 66 69 6c 69 6e 67 |e current filing| 000000d0 20 73 79 73 74 65 6d 3a 0a 0a 2a 44 49 53 43 0a | system:..*DISC.| 000000e0 2a 44 49 53 43 0a 2a 41 44 46 53 0a 2a 46 41 44 |*DISC.*ADFS.*FAD| 000000f0 46 53 0a 0a 49 6e 20 61 64 64 69 74 69 6f 6e 2c |FS..In addition,| 00000100 20 74 68 65 20 66 6f 6c 6c 6f 77 69 6e 67 20 63 | the following c| 00000110 6f 6d 6d 61 6e 64 73 20 61 72 65 20 6f 66 66 65 |ommands are offe| 00000120 72 65 64 3a 0a 0a 2a 51 75 69 74 20 20 20 20 20 |red:..*Quit | 00000130 20 28 52 65 74 75 72 6e 20 74 6f 20 74 68 65 20 | (Return to the | 00000140 64 65 73 6b 74 6f 70 29 0a 2a 44 65 73 6b 74 6f |desktop).*Deskto| 00000150 70 20 20 20 28 52 65 74 75 72 6e 20 74 6f 20 74 |p (Return to t| 00000160 68 65 20 64 65 73 6b 74 6f 70 29 0a 2a 53 68 61 |he desktop).*Sha| 00000170 64 6f 77 20 20 20 20 28 64 75 6d 6d 79 20 63 6f |dow (dummy co| 00000180 6d 6d 61 6e 64 29 0a 2a 53 52 4c 6f 61 64 20 20 |mmand).*SRLoad | 00000190 20 20 28 6c 6f 61 64 20 69 6d 61 67 65 20 69 6e | (load image in| 000001a0 74 6f 20 73 69 64 65 77 61 79 73 20 52 41 4d 29 |to sideways RAM)| 000001b0 0a 2a 53 52 57 72 69 74 65 20 20 20 28 63 6f 70 |.*SRWrite (cop| 000001c0 79 20 6d 65 6d 6f 72 79 20 69 6e 74 6f 20 73 69 |y memory into si| 000001d0 64 65 77 61 79 73 20 52 41 4d 29 0a 0a 49 6d 61 |deways RAM)..Ima| 000001e0 67 65 44 46 53 20 61 6e 64 20 36 35 30 32 45 6d |geDFS and 6502Em| 000001f0 0a 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |.---------------| 00000200 2d 2d 2d 2d 0a 0a 49 6d 61 67 65 44 46 53 20 69 |----..ImageDFS i| 00000210 73 20 61 76 61 69 6c 61 62 6c 65 20 66 72 6f 6d |s available from| 00000220 20 57 53 53 2e 0a 0a 50 61 72 74 69 61 6c 20 65 | WSS...Partial e| 00000230 6d 75 6c 61 74 69 6f 6e 20 6f 66 20 4f 53 57 4f |mulation of OSWO| 00000240 52 44 20 26 37 32 20 61 6e 64 20 26 37 46 20 69 |RD &72 and &7F i| 00000250 73 20 70 65 72 66 6f 72 6d 65 64 20 62 79 20 36 |s performed by 6| 00000260 35 30 32 45 6d 2e 0a 41 20 6d 75 63 68 20 66 75 |502Em..A much fu| 00000270 6c 6c 65 72 20 69 6d 70 6c 65 6d 65 6e 74 61 74 |ller implementat| 00000280 69 6f 6e 20 6f 66 20 4f 53 57 4f 52 44 20 26 37 |ion of OSWORD &7| 00000290 46 20 69 73 20 6f 66 66 65 72 65 64 20 62 79 20 |F is offered by | 000002a0 49 6d 61 67 65 44 46 53 2e 0a 0a 45 76 65 6e 20 |ImageDFS...Even | 000002b0 69 66 20 49 6d 61 67 65 44 46 53 20 69 73 20 6e |if ImageDFS is n| 000002c0 6f 74 20 6c 6f 61 64 65 64 2c 20 2a 44 52 49 56 |ot loaded, *DRIV| 000002d0 45 20 61 73 73 75 6d 65 73 20 74 68 61 74 20 79 |E assumes that y| 000002e0 6f 75 20 61 72 65 20 72 75 6e 6e 69 6e 67 0a 66 |ou are running.f| 000002f0 72 6f 6d 20 61 20 44 46 53 20 64 69 73 63 20 74 |rom a DFS disc t| 00000300 68 61 74 20 68 61 73 20 62 65 65 6e 20 63 6f 70 |hat has been cop| 00000310 69 65 64 20 74 6f 20 41 44 46 53 2e 20 53 6f 20 |ied to ADFS. So | 00000320 66 6f 72 20 65 78 61 6d 70 6c 65 0a 2a 44 52 49 |for example.*DRI| 00000330 56 45 20 32 20 77 69 6c 6c 20 61 74 74 65 6d 70 |VE 2 will attemp| 00000340 74 20 74 6f 20 63 68 61 6e 67 65 20 74 6f 20 74 |t to change to t| 00000350 68 65 20 64 69 72 65 63 74 6f 72 79 20 27 44 46 |he directory 'DF| 00000360 53 53 69 64 65 32 27 2e 0a 0a 48 6f 77 65 76 65 |SSide2'...Howeve| 00000370 72 20 69 66 20 49 6d 61 67 65 44 46 53 20 69 73 |r if ImageDFS is| 00000380 20 6c 6f 61 64 65 64 2c 20 2a 44 52 49 56 45 20 | loaded, *DRIVE | 00000390 3c 6e 3e 20 77 69 6c 6c 20 63 68 61 6e 67 65 20 |<n> will change | 000003a0 64 69 72 65 63 74 6f 72 79 0a 74 6f 20 61 63 63 |directory.to acc| 000003b0 65 73 73 20 61 20 70 68 79 73 69 63 61 6c 20 66 |ess a physical f| 000003c0 6c 6f 70 70 79 20 64 72 69 76 65 20 75 6e 6c 65 |loppy drive unle| 000003d0 73 73 20 61 20 44 46 53 49 6d 61 67 65 20 68 61 |ss a DFSImage ha| 000003e0 73 20 62 65 65 6e 0a 64 72 6f 70 70 65 64 20 6f |s been.dropped o| 000003f0 6e 74 6f 20 36 35 30 32 45 6d 27 73 20 69 63 6f |nto 6502Em's ico| 00000400 6e 2c 20 69 6e 20 77 68 69 63 68 20 63 61 73 65 |n, in which case| 00000410 20 69 74 20 77 69 6c 6c 20 62 65 68 61 76 65 20 | it will behave | 00000420 61 73 20 61 62 6f 76 65 2e 0a 0a 54 6f 20 61 63 |as above...To ac| 00000430 63 65 73 73 20 61 20 70 68 79 73 69 63 61 6c 20 |cess a physical | 00000440 66 6c 6f 70 70 79 20 64 72 69 76 65 20 69 66 20 |floppy drive if | 00000450 49 6d 61 67 65 44 46 53 20 69 73 20 6e 6f 77 20 |ImageDFS is now | 00000460 6c 6f 61 64 65 64 2c 0a 2a 4d 6f 75 6e 74 20 3c |loaded,.*Mount <| 00000470 6e 3e 20 73 68 6f 75 6c 64 20 62 65 20 75 73 65 |n> should be use| 00000480 64 2e 0a 0a 43 68 61 6e 67 69 6e 67 20 44 69 72 |d...Changing Dir| 00000490 65 63 74 6f 72 79 0a 2d 2d 2d 2d 2d 2d 2d 2d 2d |ectory.---------| 000004a0 2d 2d 2d 2d 2d 2d 2d 2d 2d 0a 0a 54 68 65 20 44 |---------..The D| 000004b0 46 53 20 66 69 6c 69 6e 67 20 73 79 73 74 65 6d |FS filing system| 000004c0 20 73 74 72 75 63 74 75 72 65 20 69 73 20 66 75 | structure is fu| 000004d0 6c 6c 79 20 65 6d 75 6c 61 74 65 64 0a 62 79 20 |lly emulated.by | 000004e0 6e 6f 74 69 63 69 6e 67 20 77 68 65 6e 20 61 6e |noticing when an| 000004f0 20 41 44 46 53 20 64 69 72 65 63 74 6f 72 79 27 | ADFS directory'| 00000500 73 20 6e 61 6d 65 20 69 73 20 6f 6e 65 0a 6c 65 |s name is one.le| 00000510 74 74 65 72 20 6c 6f 6e 67 2e 0a 0a 65 67 20 69 |tter long...eg i| 00000520 66 20 79 6f 75 72 20 43 75 72 72 65 6e 74 6c 79 |f your Currently| 00000530 20 53 65 6c 65 63 74 65 64 20 44 69 72 65 63 74 | Selected Direct| 00000540 6f 72 79 20 28 43 53 44 29 0a 69 73 20 41 44 46 |ory (CSD).is ADF| 00000550 53 3a 3a 48 44 2e 24 2e 42 42 43 2e 47 61 6d 65 |S::HD.$.BBC.Game| 00000560 73 2e 4a 20 74 68 65 6e 3a 0a 0a 2a 44 49 52 20 |s.J then:..*DIR | 00000570 4b 20 77 69 6c 6c 20 61 74 74 65 6d 70 74 20 74 |K will attempt t| 00000580 6f 20 73 65 74 20 74 68 65 20 43 53 44 20 74 6f |o set the CSD to| 00000590 20 41 44 46 53 3a 3a 48 44 2e 24 2e 42 42 43 2e | ADFS::HD.$.BBC.| 000005a0 47 61 6d 65 73 2e 4b 0a 0a 2a 44 49 52 20 4a 20 |Games.K..*DIR J | 000005b0 77 69 6c 6c 20 6c 65 61 76 65 20 74 68 65 20 43 |will leave the C| 000005c0 53 44 20 75 6e 61 6c 74 65 72 65 64 0a 0a 2a 44 |SD unaltered..*D| 000005d0 49 52 20 24 20 77 69 6c 6c 20 73 65 74 20 74 68 |IR $ will set th| 000005e0 65 20 43 53 44 20 74 6f 20 41 44 46 53 3a 3a 48 |e CSD to ADFS::H| 000005f0 44 2e 24 2e 42 42 43 2e 47 61 6d 65 73 0a 28 74 |D.$.BBC.Games.(t| 00000600 6f 20 63 68 61 6e 67 65 20 74 6f 20 74 68 65 20 |o change to the | 00000610 22 72 65 61 6c 22 20 72 6f 6f 74 20 64 69 72 65 |"real" root dire| 00000620 63 74 6f 72 79 2c 20 75 73 65 20 2a 44 49 52 20 |ctory, use *DIR | 00000630 3a 34 2e 24 29 0a 0a 2a 44 49 52 20 5e 20 77 69 |:4.$)..*DIR ^ wi| 00000640 6c 6c 20 73 65 74 20 74 68 65 20 43 53 44 20 74 |ll set the CSD t| 00000650 6f 20 41 44 46 53 3a 3a 48 44 2e 24 2e 42 42 43 |o ADFS::HD.$.BBC| 00000660 2e 47 61 6d 65 73 0a 0a 65 67 20 69 66 20 79 6f |.Games..eg if yo| 00000670 75 72 20 43 53 44 20 69 73 20 41 44 46 53 3a 3a |ur CSD is ADFS::| 00000680 48 44 2e 24 2e 42 42 43 2e 47 61 6d 65 73 20 74 |HD.$.BBC.Games t| 00000690 68 65 6e 3a 0a 0a 2a 44 49 52 20 24 20 77 69 6c |hen:..*DIR $ wil| 000006a0 6c 20 6c 65 61 76 65 20 74 68 65 20 43 53 44 20 |l leave the CSD | 000006b0 75 6e 63 68 61 6e 67 65 64 0a 0a 2a 44 49 52 20 |unchanged..*DIR | 000006c0 5e 20 77 69 6c 6c 20 73 65 74 20 74 68 65 20 43 |^ will set the C| 000006d0 53 44 20 74 6f 20 41 44 46 53 3a 3a 48 44 2e 24 |SD to ADFS::HD.$| 000006e0 2e 42 42 43 0a 0a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a |.BBC..**********| 000006f0 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a |****************| * 00000720 2a 2a 2a 0a 2a 20 20 49 66 20 79 6f 75 72 20 43 |***.* If your C| 00000730 53 44 20 69 73 20 73 65 74 20 74 6f 20 41 44 46 |SD is set to ADF| 00000740 53 3a 3a 48 44 2e 24 2e 42 42 43 2e 47 2e 4c 20 |S::HD.$.BBC.G.L | 00000750 74 68 65 6e 20 61 6d 62 69 67 75 69 74 79 20 20 |then ambiguity | 00000760 2a 0a 2a 20 20 63 61 6e 20 61 72 69 73 65 2c 20 |*.* can arise, | 00000770 73 6f 20 73 69 6e 67 6c 65 20 6c 65 74 74 65 72 |so single letter| 00000780 20 64 69 72 65 63 74 6f 72 69 65 73 20 73 68 6f | directories sho| 00000790 75 6c 64 20 4e 4f 54 20 62 65 20 20 20 20 2a 0a |uld NOT be *.| 000007a0 2a 20 20 75 73 65 64 20 77 69 74 68 69 6e 20 65 |* used within e| 000007b0 61 63 68 20 6f 74 68 65 72 2e 20 20 20 20 20 20 |ach other. | 000007c0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000007d0 20 20 20 20 20 20 20 20 20 20 20 20 2a 0a 2a 2a | *.**| 000007e0 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a |****************| * 00000810 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 0a 0a 44 72 69 |***********..Dri| 00000820 76 65 20 6e 75 6d 62 65 72 73 20 77 69 74 68 69 |ve numbers withi| 00000830 6e 20 66 69 6c 65 6e 61 6d 65 73 20 28 65 67 20 |n filenames (eg | 00000840 3a 30 2e 45 2e 4a 61 6d 65 73 6f 6e 29 20 61 72 |:0.E.Jameson) ar| 00000850 65 20 69 67 6e 6f 72 65 64 0a 73 6f 20 74 68 61 |e ignored.so tha| 00000860 74 20 79 6f 75 20 63 61 6e 20 73 61 76 65 20 70 |t you can save p| 00000870 6f 73 69 74 69 6f 6e 73 20 6f 66 20 67 61 6d 65 |ositions of game| 00000880 73 20 6f 6e 74 6f 20 79 6f 75 72 20 68 61 72 64 |s onto your hard| 00000890 20 64 69 73 63 2e 0a 54 6f 20 73 70 65 63 69 66 | disc..To specif| 000008a0 79 20 61 20 64 72 69 76 65 2c 20 75 73 65 20 41 |y a drive, use A| 000008b0 44 46 53 3a 3a 30 2e 4a 61 6d 65 73 6f 6e 0a 0a |DFS::0.Jameson..| 000008c0 2a 4d 6f 75 6e 74 20 69 73 20 69 67 6e 6f 72 65 |*Mount is ignore| 000008d0 64 0a 54 6f 20 63 68 61 6e 67 65 20 64 72 69 76 |d.To change driv| 000008e0 65 20 75 73 65 20 2a 44 49 52 20 3a 30 2c 20 2a |e use *DIR :0, *| 000008f0 44 49 52 20 41 44 46 53 3a 3a 30 2c 20 2a 44 49 |DIR ADFS::0, *DI| 00000900 52 20 41 44 46 53 3a 3a 48 44 20 65 74 63 0a 0a |R ADFS::HD etc..| 00000910 52 49 53 43 20 4f 53 27 73 20 43 53 44 20 69 73 |RISC OS's CSD is| 00000920 20 6e 6f 74 20 63 68 61 6e 67 65 64 20 62 79 20 | not changed by | 00000930 74 68 65 20 65 6d 75 6c 61 74 6f 72 2c 20 61 6c |the emulator, al| 00000940 6c 6f 77 69 6e 67 0a 73 65 76 65 72 61 6c 20 69 |lowing.several i| 00000950 6e 63 61 72 6e 61 74 69 6f 6e 73 20 6f 66 20 74 |ncarnations of t| 00000960 68 65 20 65 6d 75 6c 61 74 6f 72 20 74 6f 20 62 |he emulator to b| 00000970 65 20 61 63 74 69 76 65 2e 0a 0a 53 6f 6d 65 20 |e active...Some | 00000980 66 69 6c 69 6e 67 20 73 79 73 74 65 6d 73 20 28 |filing systems (| 00000990 65 67 20 44 4f 53 46 53 29 20 64 6f 20 6e 6f 74 |eg DOSFS) do not| 000009a0 20 73 75 70 70 6f 72 74 20 4f 53 47 42 50 42 20 | support OSGBPB | 000009b0 38 2c 0a 73 6f 20 70 72 6f 67 72 61 6d 73 20 74 |8,.so programs t| 000009c0 68 61 74 20 75 73 65 20 69 74 20 77 69 6c 6c 20 |hat use it will | 000009d0 6e 6f 74 20 77 6f 72 6b 20 6f 6e 20 73 75 63 68 |not work on such| 000009e0 20 66 69 6c 69 6e 67 20 73 79 73 74 65 6d 73 2e | filing systems.| 000009f0 0a 0a 4f 53 46 53 43 2c 20 4f 53 46 49 4e 44 2c |..OSFSC, OSFIND,| 00000a00 20 4f 53 47 42 50 42 2c 20 4f 53 42 50 55 54 2c | OSGBPB, OSBPUT,| 00000a10 20 4f 53 42 47 45 54 2c 20 4f 53 41 52 47 53 2c | OSBGET, OSARGS,| 00000a20 20 4f 53 46 49 4c 45 0a 61 72 65 20 61 6c 6c 20 | OSFILE.are all | 00000a30 66 75 6c 6c 79 20 73 75 70 70 6f 72 74 65 64 2e |fully supported.| 00000a40 0a 0a 49 6e 20 61 64 64 69 74 69 6f 6e 2c 20 4f |..In addition, O| 00000a50 53 47 42 50 42 20 39 20 69 73 20 70 61 72 74 69 |SGBPB 9 is parti| 00000a60 61 6c 6c 79 20 73 75 70 70 6f 72 74 65 64 20 28 |ally supported (| 00000a70 66 6f 72 20 74 68 65 0a 63 75 72 72 65 6e 74 20 |for the.current | 00000a80 64 69 72 65 63 74 6f 72 79 29 3a 0a 0a 62 6c 6f |directory):..blo| 00000a90 63 6b 3f 30 3d 6e 75 6d 62 65 72 20 6f 66 20 66 |ck?0=number of f| 00000aa0 69 6c 65 73 20 74 6f 20 72 65 61 64 20 28 6e 75 |iles to read (nu| 00000ab0 6d 62 65 72 20 6f 66 20 66 69 6c 65 73 20 72 65 |mber of files re| 00000ac0 61 64 29 0a 62 6c 6f 63 6b 21 31 3d 61 64 64 72 |ad).block!1=addr| 00000ad0 65 73 73 20 69 6e 20 6d 65 6d 6f 72 79 20 6f 66 |ess in memory of| 00000ae0 20 64 61 74 61 0a 62 6c 6f 63 6b 21 35 3d 6c 65 | data.block!5=le| 00000af0 6e 67 74 68 20 6f 66 20 64 61 74 61 20 62 6c 6f |ngth of data blo| 00000b00 63 6b 0a 62 6c 6f 63 6b 21 39 3d 73 65 71 75 65 |ck.block!9=seque| 00000b10 6e 74 69 61 6c 20 70 6f 69 6e 74 65 72 20 28 30 |ntial pointer (0| 00000b20 20 66 6f 72 20 66 69 72 73 74 20 63 61 6c 6c 2c | for first call,| 00000b30 20 2d 31 20 77 68 65 6e 20 66 69 6e 69 73 68 65 | -1 when finishe| 00000b40 64 29 0a 0a 52 49 53 43 20 4f 53 20 65 72 72 6f |d)..RISC OS erro| 00000b50 72 73 20 61 72 65 20 70 61 73 73 65 64 20 62 61 |rs are passed ba| 00000b60 63 6b 20 69 6e 74 6f 20 74 68 65 20 65 6d 75 6c |ck into the emul| 00000b70 61 74 6f 72 20 76 69 61 20 42 52 4b 2e 0a 0a 46 |ator via BRK...F| 00000b80 69 6c 69 6e 67 20 73 79 73 74 65 6d 20 6f 70 65 |iling system ope| 00000b90 72 61 74 69 6f 6e 73 20 61 70 70 65 61 72 20 69 |rations appear i| 00000ba0 6e 73 74 61 6e 74 61 6e 65 6f 75 73 20 74 6f 20 |nstantaneous to | 00000bb0 74 68 65 20 65 6d 75 6c 61 74 6f 72 0a 28 69 65 |the emulator.(ie| 00000bc0 20 64 6f 20 6e 6f 74 20 72 75 6e 20 66 69 6c 69 | do not run fili| 00000bd0 6e 67 20 73 79 73 74 65 6d 20 62 65 6e 63 68 6d |ng system benchm| 00000be0 61 72 6b 73 20 77 69 74 68 69 6e 20 74 68 65 20 |arks within the | 00000bf0 65 6d 75 6c 61 74 6f 72 21 29 0a 0a 41 6c 74 68 |emulator!)..Alth| 00000c00 6f 75 67 68 20 74 68 65 20 6f 70 65 72 61 74 69 |ough the operati| 00000c10 6e 67 20 73 79 73 74 65 6d 20 6e 6f 72 6d 61 6c |ng system normal| 00000c20 6c 79 20 61 70 70 65 61 72 73 20 74 6f 20 62 65 |ly appears to be| 00000c30 20 52 4f 4d 2c 0a 69 74 20 63 61 6e 20 62 65 20 | ROM,.it can be | 00000c40 6f 76 65 72 77 72 69 74 74 65 6e 20 62 79 20 66 |overwritten by f| 00000c50 69 6c 69 6e 67 20 73 79 73 74 65 6d 20 63 61 6c |iling system cal| 00000c60 6c 73 20 28 65 67 20 2a 4c 6f 61 64 29 0a 0a 46 |ls (eg *Load)..F| 00000c70 69 6c 65 73 20 74 68 61 74 20 77 69 6c 6c 20 65 |iles that will e| 00000c80 78 74 65 6e 64 20 62 65 79 6f 6e 64 20 26 46 46 |xtend beyond &FF| 00000c90 46 46 20 77 69 6c 6c 20 67 65 6e 65 72 61 74 65 |FF will generate| 00000ca0 20 61 6e 20 65 72 72 6f 72 0a 69 66 20 79 6f 75 | an error.if you| 00000cb0 20 74 72 79 20 74 6f 20 6c 6f 61 64 20 74 68 65 | try to load the| 00000cc0 6d 2e 0a 28 6e 6f 72 6d 61 6c 6c 79 20 66 69 6c |m..(normally fil| 00000cd0 65 73 20 6d 69 67 68 74 20 77 72 61 70 20 72 6f |es might wrap ro| 00000ce0 75 6e 64 20 62 61 63 6b 20 74 6f 20 26 30 30 30 |und back to &000| 00000cf0 30 29 0a |0).| 00000cf3
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