Home » Archimedes archive » Acorn Computing » 1994 11.adf » 9411 » TechForum/DASpatch/ReadMe
TechForum/DASpatch/ReadMe
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 » Acorn Computing » 1994 11.adf » 9411 |
| Filename: | TechForum/DASpatch/ReadMe |
| Read OK: | ✔ |
| File size: | 0ACF bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
Back in the 1993 Special issue, I mentioned a small problem with DragASprite v 0.03, & Acorn still have yet to release a sofloaded replacement, for RISC OS 3.1 machines, which fixes this bug. Recall, there is a single faulty instruction in the module which can screw up initial sprite alignment within its drag box. For top alignment, the original code uses sprite width in a calculation that should use height. The resulting error in initial sprite position may only be cosmetic, but it can be very noticeable when it does occur. I recently wanted to distribute an application which required this bug be fixed, & although, as described in the December '93 TechForum, I had patched a single copy of DragASprite, due to copyright restrictions I couldn't distribute this. The original BASIC routine which I wrote to patch the module could itself have been distributed, as it was with TechForum, however to non-programming users it was rather cumbersome, so instead I've written a short ARM code utility which has the similar effect of patching the module, but does so only temporarily - upto the next hard reset - each time it is run. Unlike the former routine which saved the patched module to disc for manual loading & relied on the user only using it if she did indeed have the bugged 0.03 version, this one can be executed from an application's !Run file to automatically patch & reinitialise the module, if appropriate, such that the end user need know nothing about what is going on. Most importantly, this code takes much more care to ensure that the version of DragASprite currently present is this bugged one, before it makes any modifications, so it should be safe to run on any machine. When run, if there is no version present or it is pre 0.03, no patch can occur. If it is 0.03 & it still contains the bug, it will be fixed if possible, whereas if the version is post 0.03, it shouldn't need fixing & will be left alone. The bugged version is identified by checking the module length, the specific instruction to be changed, & by performing an OS_CRC on the whole module. The utility is only 640 bytes long. I've included the source code for your perusal, in directory 's'. It's usually silent in operation, however if you add the argument 'verbose' to its command tail, you will get a report on the action taken, via Wimp_ReportError. Assuming you put DASpatch into your application directory, I suggest you call it from !Run using something like: SetEval App$DAS3 0 RMEnsure DragASprite 0.04 SetEval App$DAS3 -1 RMEnsure DragASprite 0.03 SetEval App$DAS3 0 If App$DAS3 Then Run <App$Dir>.DASpatch UnSet App$DAS3 | NB Use | If App$DAS3 Then Run <App$Dir>.DASpatch verbose | instead of the similar line above, to get a report on action taken
00000000 0a 42 61 63 6b 20 69 6e 20 74 68 65 20 31 39 39 |.Back in the 199| 00000010 33 20 53 70 65 63 69 61 6c 20 69 73 73 75 65 2c |3 Special issue,| 00000020 20 49 20 6d 65 6e 74 69 6f 6e 65 64 20 61 20 73 | I mentioned a s| 00000030 6d 61 6c 6c 20 70 72 6f 62 6c 65 6d 20 77 69 74 |mall problem wit| 00000040 68 0a 44 72 61 67 41 53 70 72 69 74 65 20 76 20 |h.DragASprite v | 00000050 30 2e 30 33 2c 20 26 20 41 63 6f 72 6e 20 73 74 |0.03, & Acorn st| 00000060 69 6c 6c 20 68 61 76 65 20 79 65 74 20 74 6f 20 |ill have yet to | 00000070 72 65 6c 65 61 73 65 20 61 20 73 6f 66 6c 6f 61 |release a sofloa| 00000080 64 65 64 0a 72 65 70 6c 61 63 65 6d 65 6e 74 2c |ded.replacement,| 00000090 20 66 6f 72 20 52 49 53 43 20 4f 53 20 33 2e 31 | for RISC OS 3.1| 000000a0 20 6d 61 63 68 69 6e 65 73 2c 20 77 68 69 63 68 | machines, which| 000000b0 20 66 69 78 65 73 20 74 68 69 73 20 62 75 67 2e | fixes this bug.| 000000c0 0a 0a 52 65 63 61 6c 6c 2c 20 74 68 65 72 65 20 |..Recall, there | 000000d0 69 73 20 61 20 73 69 6e 67 6c 65 20 66 61 75 6c |is a single faul| 000000e0 74 79 20 69 6e 73 74 72 75 63 74 69 6f 6e 20 69 |ty instruction i| 000000f0 6e 20 74 68 65 20 6d 6f 64 75 6c 65 20 77 68 69 |n the module whi| 00000100 63 68 0a 63 61 6e 20 73 63 72 65 77 20 75 70 20 |ch.can screw up | 00000110 69 6e 69 74 69 61 6c 20 73 70 72 69 74 65 20 61 |initial sprite a| 00000120 6c 69 67 6e 6d 65 6e 74 20 77 69 74 68 69 6e 20 |lignment within | 00000130 69 74 73 20 64 72 61 67 20 62 6f 78 2e 20 46 6f |its drag box. Fo| 00000140 72 20 74 6f 70 0a 61 6c 69 67 6e 6d 65 6e 74 2c |r top.alignment,| 00000150 20 74 68 65 20 6f 72 69 67 69 6e 61 6c 20 63 6f | the original co| 00000160 64 65 20 75 73 65 73 20 73 70 72 69 74 65 20 77 |de uses sprite w| 00000170 69 64 74 68 20 69 6e 20 61 20 63 61 6c 63 75 6c |idth in a calcul| 00000180 61 74 69 6f 6e 20 74 68 61 74 0a 73 68 6f 75 6c |ation that.shoul| 00000190 64 20 75 73 65 20 68 65 69 67 68 74 2e 0a 0a 54 |d use height...T| 000001a0 68 65 20 72 65 73 75 6c 74 69 6e 67 20 65 72 72 |he resulting err| 000001b0 6f 72 20 69 6e 20 69 6e 69 74 69 61 6c 20 73 70 |or in initial sp| 000001c0 72 69 74 65 20 70 6f 73 69 74 69 6f 6e 20 6d 61 |rite position ma| 000001d0 79 20 6f 6e 6c 79 20 62 65 20 63 6f 73 6d 65 74 |y only be cosmet| 000001e0 69 63 2c 0a 62 75 74 20 69 74 20 63 61 6e 20 62 |ic,.but it can b| 000001f0 65 20 76 65 72 79 20 6e 6f 74 69 63 65 61 62 6c |e very noticeabl| 00000200 65 20 77 68 65 6e 20 69 74 20 64 6f 65 73 20 6f |e when it does o| 00000210 63 63 75 72 2e 0a 0a 49 20 72 65 63 65 6e 74 6c |ccur...I recentl| 00000220 79 20 77 61 6e 74 65 64 20 74 6f 20 64 69 73 74 |y wanted to dist| 00000230 72 69 62 75 74 65 20 61 6e 20 61 70 70 6c 69 63 |ribute an applic| 00000240 61 74 69 6f 6e 20 77 68 69 63 68 20 72 65 71 75 |ation which requ| 00000250 69 72 65 64 20 74 68 69 73 20 62 75 67 0a 62 65 |ired this bug.be| 00000260 20 66 69 78 65 64 2c 20 26 20 61 6c 74 68 6f 75 | fixed, & althou| 00000270 67 68 2c 20 61 73 20 64 65 73 63 72 69 62 65 64 |gh, as described| 00000280 20 69 6e 20 74 68 65 20 44 65 63 65 6d 62 65 72 | in the December| 00000290 20 27 39 33 20 54 65 63 68 46 6f 72 75 6d 2c 20 | '93 TechForum, | 000002a0 49 0a 68 61 64 20 70 61 74 63 68 65 64 20 61 20 |I.had patched a | 000002b0 73 69 6e 67 6c 65 20 63 6f 70 79 20 6f 66 20 44 |single copy of D| 000002c0 72 61 67 41 53 70 72 69 74 65 2c 20 64 75 65 20 |ragASprite, due | 000002d0 74 6f 20 63 6f 70 79 72 69 67 68 74 0a 72 65 73 |to copyright.res| 000002e0 74 72 69 63 74 69 6f 6e 73 20 49 20 63 6f 75 6c |trictions I coul| 000002f0 64 6e 27 74 20 64 69 73 74 72 69 62 75 74 65 20 |dn't distribute | 00000300 74 68 69 73 2e 0a 0a 54 68 65 20 6f 72 69 67 69 |this...The origi| 00000310 6e 61 6c 20 42 41 53 49 43 20 72 6f 75 74 69 6e |nal BASIC routin| 00000320 65 20 77 68 69 63 68 20 49 20 77 72 6f 74 65 20 |e which I wrote | 00000330 74 6f 20 70 61 74 63 68 20 74 68 65 20 6d 6f 64 |to patch the mod| 00000340 75 6c 65 20 63 6f 75 6c 64 0a 69 74 73 65 6c 66 |ule could.itself| 00000350 20 68 61 76 65 20 62 65 65 6e 20 64 69 73 74 72 | have been distr| 00000360 69 62 75 74 65 64 2c 20 61 73 20 69 74 20 77 61 |ibuted, as it wa| 00000370 73 20 77 69 74 68 20 54 65 63 68 46 6f 72 75 6d |s with TechForum| 00000380 2c 20 68 6f 77 65 76 65 72 20 74 6f 0a 6e 6f 6e |, however to.non| 00000390 2d 70 72 6f 67 72 61 6d 6d 69 6e 67 20 75 73 65 |-programming use| 000003a0 72 73 20 69 74 20 77 61 73 20 72 61 74 68 65 72 |rs it was rather| 000003b0 20 63 75 6d 62 65 72 73 6f 6d 65 2c 20 73 6f 20 | cumbersome, so | 000003c0 69 6e 73 74 65 61 64 20 49 27 76 65 0a 77 72 69 |instead I've.wri| 000003d0 74 74 65 6e 20 61 20 73 68 6f 72 74 20 41 52 4d |tten a short ARM| 000003e0 20 63 6f 64 65 20 75 74 69 6c 69 74 79 20 77 68 | code utility wh| 000003f0 69 63 68 20 68 61 73 20 74 68 65 20 73 69 6d 69 |ich has the simi| 00000400 6c 61 72 20 65 66 66 65 63 74 20 6f 66 0a 70 61 |lar effect of.pa| 00000410 74 63 68 69 6e 67 20 74 68 65 20 6d 6f 64 75 6c |tching the modul| 00000420 65 2c 20 62 75 74 20 64 6f 65 73 20 73 6f 20 6f |e, but does so o| 00000430 6e 6c 79 20 74 65 6d 70 6f 72 61 72 69 6c 79 20 |nly temporarily | 00000440 2d 20 75 70 74 6f 20 74 68 65 20 6e 65 78 74 20 |- upto the next | 00000450 68 61 72 64 0a 72 65 73 65 74 20 2d 20 65 61 63 |hard.reset - eac| 00000460 68 20 74 69 6d 65 20 69 74 20 69 73 20 72 75 6e |h time it is run| 00000470 2e 0a 0a 55 6e 6c 69 6b 65 20 74 68 65 20 66 6f |...Unlike the fo| 00000480 72 6d 65 72 20 72 6f 75 74 69 6e 65 20 77 68 69 |rmer routine whi| 00000490 63 68 20 73 61 76 65 64 20 74 68 65 20 70 61 74 |ch saved the pat| 000004a0 63 68 65 64 20 6d 6f 64 75 6c 65 20 74 6f 20 64 |ched module to d| 000004b0 69 73 63 20 66 6f 72 0a 6d 61 6e 75 61 6c 20 6c |isc for.manual l| 000004c0 6f 61 64 69 6e 67 20 26 20 72 65 6c 69 65 64 20 |oading & relied | 000004d0 6f 6e 20 74 68 65 20 75 73 65 72 20 6f 6e 6c 79 |on the user only| 000004e0 20 75 73 69 6e 67 20 69 74 20 69 66 20 73 68 65 | using it if she| 000004f0 20 64 69 64 20 69 6e 64 65 65 64 0a 68 61 76 65 | did indeed.have| 00000500 20 74 68 65 20 62 75 67 67 65 64 20 30 2e 30 33 | the bugged 0.03| 00000510 20 76 65 72 73 69 6f 6e 2c 20 74 68 69 73 20 6f | version, this o| 00000520 6e 65 20 63 61 6e 20 62 65 20 65 78 65 63 75 74 |ne can be execut| 00000530 65 64 20 66 72 6f 6d 20 61 6e 0a 61 70 70 6c 69 |ed from an.appli| 00000540 63 61 74 69 6f 6e 27 73 20 21 52 75 6e 20 66 69 |cation's !Run fi| 00000550 6c 65 20 74 6f 20 61 75 74 6f 6d 61 74 69 63 61 |le to automatica| 00000560 6c 6c 79 20 70 61 74 63 68 20 26 20 72 65 69 6e |lly patch & rein| 00000570 69 74 69 61 6c 69 73 65 20 74 68 65 0a 6d 6f 64 |itialise the.mod| 00000580 75 6c 65 2c 20 69 66 20 61 70 70 72 6f 70 72 69 |ule, if appropri| 00000590 61 74 65 2c 20 73 75 63 68 20 74 68 61 74 20 74 |ate, such that t| 000005a0 68 65 20 65 6e 64 20 75 73 65 72 20 6e 65 65 64 |he end user need| 000005b0 20 6b 6e 6f 77 20 6e 6f 74 68 69 6e 67 20 61 62 | know nothing ab| 000005c0 6f 75 74 0a 77 68 61 74 20 69 73 20 67 6f 69 6e |out.what is goin| 000005d0 67 20 6f 6e 2e 0a 0a 4d 6f 73 74 20 69 6d 70 6f |g on...Most impo| 000005e0 72 74 61 6e 74 6c 79 2c 20 74 68 69 73 20 63 6f |rtantly, this co| 000005f0 64 65 20 74 61 6b 65 73 20 6d 75 63 68 20 6d 6f |de takes much mo| 00000600 72 65 20 63 61 72 65 20 74 6f 20 65 6e 73 75 72 |re care to ensur| 00000610 65 20 74 68 61 74 20 74 68 65 0a 76 65 72 73 69 |e that the.versi| 00000620 6f 6e 20 6f 66 20 44 72 61 67 41 53 70 72 69 74 |on of DragASprit| 00000630 65 20 63 75 72 72 65 6e 74 6c 79 20 70 72 65 73 |e currently pres| 00000640 65 6e 74 20 69 73 20 74 68 69 73 20 62 75 67 67 |ent is this bugg| 00000650 65 64 20 6f 6e 65 2c 20 62 65 66 6f 72 65 20 69 |ed one, before i| 00000660 74 0a 6d 61 6b 65 73 20 61 6e 79 20 6d 6f 64 69 |t.makes any modi| 00000670 66 69 63 61 74 69 6f 6e 73 2c 20 73 6f 20 69 74 |fications, so it| 00000680 20 73 68 6f 75 6c 64 20 62 65 20 73 61 66 65 20 | should be safe | 00000690 74 6f 20 72 75 6e 20 6f 6e 20 61 6e 79 20 6d 61 |to run on any ma| 000006a0 63 68 69 6e 65 2e 0a 0a 57 68 65 6e 20 72 75 6e |chine...When run| 000006b0 2c 20 69 66 20 74 68 65 72 65 20 69 73 20 6e 6f |, if there is no| 000006c0 20 76 65 72 73 69 6f 6e 20 70 72 65 73 65 6e 74 | version present| 000006d0 20 6f 72 20 69 74 20 69 73 20 70 72 65 20 30 2e | or it is pre 0.| 000006e0 30 33 2c 20 6e 6f 20 70 61 74 63 68 0a 63 61 6e |03, no patch.can| 000006f0 20 6f 63 63 75 72 2e 20 49 66 20 69 74 20 69 73 | occur. If it is| 00000700 20 30 2e 30 33 20 26 20 69 74 20 73 74 69 6c 6c | 0.03 & it still| 00000710 20 63 6f 6e 74 61 69 6e 73 20 74 68 65 20 62 75 | contains the bu| 00000720 67 2c 20 69 74 20 77 69 6c 6c 20 62 65 20 66 69 |g, it will be fi| 00000730 78 65 64 0a 69 66 20 70 6f 73 73 69 62 6c 65 2c |xed.if possible,| 00000740 20 77 68 65 72 65 61 73 20 69 66 20 74 68 65 20 | whereas if the | 00000750 76 65 72 73 69 6f 6e 20 69 73 20 70 6f 73 74 20 |version is post | 00000760 30 2e 30 33 2c 20 69 74 20 73 68 6f 75 6c 64 6e |0.03, it shouldn| 00000770 27 74 20 6e 65 65 64 0a 66 69 78 69 6e 67 20 26 |'t need.fixing &| 00000780 20 77 69 6c 6c 20 62 65 20 6c 65 66 74 20 61 6c | will be left al| 00000790 6f 6e 65 2e 0a 0a 54 68 65 20 62 75 67 67 65 64 |one...The bugged| 000007a0 20 76 65 72 73 69 6f 6e 20 69 73 20 69 64 65 6e | version is iden| 000007b0 74 69 66 69 65 64 20 62 79 20 63 68 65 63 6b 69 |tified by checki| 000007c0 6e 67 20 74 68 65 20 6d 6f 64 75 6c 65 20 6c 65 |ng the module le| 000007d0 6e 67 74 68 2c 20 74 68 65 0a 73 70 65 63 69 66 |ngth, the.specif| 000007e0 69 63 20 69 6e 73 74 72 75 63 74 69 6f 6e 20 74 |ic instruction t| 000007f0 6f 20 62 65 20 63 68 61 6e 67 65 64 2c 20 26 20 |o be changed, & | 00000800 62 79 20 70 65 72 66 6f 72 6d 69 6e 67 20 61 6e |by performing an| 00000810 20 4f 53 5f 43 52 43 20 6f 6e 20 74 68 65 0a 77 | OS_CRC on the.w| 00000820 68 6f 6c 65 20 6d 6f 64 75 6c 65 2e 0a 0a 54 68 |hole module...Th| 00000830 65 20 75 74 69 6c 69 74 79 20 69 73 20 6f 6e 6c |e utility is onl| 00000840 79 20 36 34 30 20 62 79 74 65 73 20 6c 6f 6e 67 |y 640 bytes long| 00000850 2e 20 49 27 76 65 20 69 6e 63 6c 75 64 65 64 20 |. I've included | 00000860 74 68 65 20 73 6f 75 72 63 65 20 63 6f 64 65 20 |the source code | 00000870 66 6f 72 0a 79 6f 75 72 20 70 65 72 75 73 61 6c |for.your perusal| 00000880 2c 20 69 6e 20 64 69 72 65 63 74 6f 72 79 20 27 |, in directory '| 00000890 73 27 2e 0a 0a 49 74 27 73 20 75 73 75 61 6c 6c |s'...It's usuall| 000008a0 79 20 73 69 6c 65 6e 74 20 69 6e 20 6f 70 65 72 |y silent in oper| 000008b0 61 74 69 6f 6e 2c 20 68 6f 77 65 76 65 72 20 69 |ation, however i| 000008c0 66 20 79 6f 75 20 61 64 64 20 74 68 65 20 61 72 |f you add the ar| 000008d0 67 75 6d 65 6e 74 0a 27 76 65 72 62 6f 73 65 27 |gument.'verbose'| 000008e0 20 74 6f 20 69 74 73 20 63 6f 6d 6d 61 6e 64 20 | to its command | 000008f0 74 61 69 6c 2c 20 79 6f 75 20 77 69 6c 6c 20 67 |tail, you will g| 00000900 65 74 20 61 20 72 65 70 6f 72 74 20 6f 6e 20 74 |et a report on t| 00000910 68 65 20 61 63 74 69 6f 6e 0a 74 61 6b 65 6e 2c |he action.taken,| 00000920 20 76 69 61 20 57 69 6d 70 5f 52 65 70 6f 72 74 | via Wimp_Report| 00000930 45 72 72 6f 72 2e 0a 0a 41 73 73 75 6d 69 6e 67 |Error...Assuming| 00000940 20 79 6f 75 20 70 75 74 20 44 41 53 70 61 74 63 | you put DASpatc| 00000950 68 20 69 6e 74 6f 20 79 6f 75 72 20 61 70 70 6c |h into your appl| 00000960 69 63 61 74 69 6f 6e 20 64 69 72 65 63 74 6f 72 |ication director| 00000970 79 2c 20 49 20 73 75 67 67 65 73 74 0a 79 6f 75 |y, I suggest.you| 00000980 20 63 61 6c 6c 20 69 74 20 66 72 6f 6d 20 21 52 | call it from !R| 00000990 75 6e 20 75 73 69 6e 67 20 73 6f 6d 65 74 68 69 |un using somethi| 000009a0 6e 67 20 6c 69 6b 65 3a 0a 0a 53 65 74 45 76 61 |ng like:..SetEva| 000009b0 6c 20 41 70 70 24 44 41 53 33 20 30 0a 52 4d 45 |l App$DAS3 0.RME| 000009c0 6e 73 75 72 65 20 44 72 61 67 41 53 70 72 69 74 |nsure DragASprit| 000009d0 65 20 30 2e 30 34 20 53 65 74 45 76 61 6c 20 41 |e 0.04 SetEval A| 000009e0 70 70 24 44 41 53 33 20 2d 31 0a 52 4d 45 6e 73 |pp$DAS3 -1.RMEns| 000009f0 75 72 65 20 44 72 61 67 41 53 70 72 69 74 65 20 |ure DragASprite | 00000a00 30 2e 30 33 20 53 65 74 45 76 61 6c 20 41 70 70 |0.03 SetEval App| 00000a10 24 44 41 53 33 20 30 0a 49 66 20 41 70 70 24 44 |$DAS3 0.If App$D| 00000a20 41 53 33 20 54 68 65 6e 20 52 75 6e 20 3c 41 70 |AS3 Then Run <Ap| 00000a30 70 24 44 69 72 3e 2e 44 41 53 70 61 74 63 68 0a |p$Dir>.DASpatch.| 00000a40 55 6e 53 65 74 20 41 70 70 24 44 41 53 33 0a 7c |UnSet App$DAS3.|| 00000a50 20 4e 42 20 55 73 65 0a 7c 20 49 66 20 41 70 70 | NB Use.| If App| 00000a60 24 44 41 53 33 20 54 68 65 6e 20 52 75 6e 20 3c |$DAS3 Then Run <| 00000a70 41 70 70 24 44 69 72 3e 2e 44 41 53 70 61 74 63 |App$Dir>.DASpatc| 00000a80 68 20 76 65 72 62 6f 73 65 0a 7c 20 69 6e 73 74 |h verbose.| inst| 00000a90 65 61 64 20 6f 66 20 74 68 65 20 73 69 6d 69 6c |ead of the simil| 00000aa0 61 72 20 6c 69 6e 65 20 61 62 6f 76 65 2c 20 74 |ar line above, t| 00000ab0 6f 20 67 65 74 20 61 20 72 65 70 6f 72 74 20 6f |o get a report o| 00000ac0 6e 20 61 63 74 69 6f 6e 20 74 61 6b 65 6e 0a |n action taken.| 00000acf
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