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V/+BRR3
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 » Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_55.ADF |
| Filename: | V/+BRR3 |
| Read OK: | ✔ |
| File size: | 0925 bytes |
| Load address: | 2B204556 |
| Exec address: | 33525242 |
Duplicates
There are 3 duplicate copies of this file in the archive:
- AEW website » eug » eug_3_5_discs_Eug-55_A-EUG55.adf » V/+BRR3
- AEW website » eug » eug_5_25_discs_Eug-55_D-EUG55.dsd » V.+BRR3
- Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_55.ADF » V/+BRR3
- Personal collection » Acorn ADFS disks » Greaseweazled » adfs_EUG_55.adf » V/+BRR3
File contents
[ BASIC ROM ROUTINES ARTICLE - CONTINUATION ]
6. Routine: Convert number in IWA to ASCII decimal or hexadecimal
Basic 2: &9EFF
Basic 4: &A138
Entry: IWA should contain number to be converted
location &15 = &FF for hexadecimal ASCII
or &15 = 0 for decimal ASCII
The previous routine only allowed 16-bit numbers (numbers in the range
0-65535) to be printed. This routine helps you print 32-bit numbers in
decimal or hex. When we speak of "hexadecimal" or "decimal ASCII", it
means that a string containing ASCII codes is made for the given number.
For example, the four ASCII decimal codes for &9EFF are 57, 69, 70, and
70 (ignoring the ampersand which Basic doesn't print anyway). Basic puts
these ASCII codes into the String Work Area, or SWA for short. We can
then use another routine to print out the contents of the SWA:
7. Routine: Print the SWA
Basic 2: &8E12
Basic 4: &921B
Entry: location &30 must contain the length of the string
the SWA must contain the string
location &A must = 0.
Ex.: LDX #&50 \copy integer at &50-3
JSR &AF56 \to SWA
LDA #&FF:STA &15 \number to be in hex
JSR &9EFF \convert IWA to ASCII codes
LDA #0:STA &A
JMP &8E12 \and print the number
8. Routine: Random number generator
Basic 2: &AF51
Basic 4: &AA7B
No entry requirements. On exit, the IWA contains a 4-byte random
integer.
Ex.: JSR &AF51
LDA &2A
JSR alien
I find this Rom routine extremely useful for getting random numbers in
games, and it's the only decent way of getting fairly unpredictable
numbers in machine code.
Conclusion
IF you use any of the above routines, don't forget to use the correct
address for your version of Basic. Now that you've seen what the Basic
Rom can do, hopefully you'll want to start exploring other parts. If you
find anything useful, do write in and let us know!
Christopher Dewhurst
24 September, 2000
EUG #55
00000000 20 20 20 20 20 20 20 20 20 20 20 20 20 5b 20 42 | [ B| 00000010 41 53 49 43 20 52 4f 4d 20 52 4f 55 54 49 4e 45 |ASIC ROM ROUTINE| 00000020 53 20 41 52 54 49 43 4c 45 20 2d 20 43 4f 4e 54 |S ARTICLE - CONT| 00000030 49 4e 55 41 54 49 4f 4e 20 5d 0d 0d 36 2e 20 20 |INUATION ]..6. | 00000040 20 20 20 20 52 6f 75 74 69 6e 65 3a 20 43 6f 6e | Routine: Con| 00000050 76 65 72 74 20 6e 75 6d 62 65 72 20 69 6e 20 49 |vert number in I| 00000060 57 41 20 74 6f 20 41 53 43 49 49 20 64 65 63 69 |WA to ASCII deci| 00000070 6d 61 6c 20 6f 72 20 68 65 78 61 64 65 63 69 6d |mal or hexadecim| 00000080 61 6c 0d 20 20 20 20 20 20 20 20 42 61 73 69 63 |al. Basic| 00000090 20 32 3a 20 26 39 45 46 46 0d 20 20 20 20 20 20 | 2: &9EFF. | 000000a0 20 20 42 61 73 69 63 20 34 3a 20 26 41 31 33 38 | Basic 4: &A138| 000000b0 0d 0d 20 20 20 20 20 20 20 20 45 6e 74 72 79 3a |.. Entry:| 000000c0 20 49 57 41 20 73 68 6f 75 6c 64 20 63 6f 6e 74 | IWA should cont| 000000d0 61 69 6e 20 6e 75 6d 62 65 72 20 74 6f 20 62 65 |ain number to be| 000000e0 20 63 6f 6e 76 65 72 74 65 64 0d 20 20 20 20 20 | converted. | 000000f0 20 20 20 20 20 20 20 20 20 20 6c 6f 63 61 74 69 | locati| 00000100 6f 6e 20 26 31 35 20 3d 20 26 46 46 20 66 6f 72 |on &15 = &FF for| 00000110 20 68 65 78 61 64 65 63 69 6d 61 6c 20 41 53 43 | hexadecimal ASC| 00000120 49 49 0d 20 20 20 20 20 20 20 20 20 20 20 20 20 |II. | 00000130 20 20 6f 72 20 20 20 20 20 20 20 26 31 35 20 3d | or &15 =| 00000140 20 30 20 20 20 66 6f 72 20 64 65 63 69 6d 61 6c | 0 for decimal| 00000150 20 41 53 43 49 49 0d 0d 54 68 65 20 70 72 65 76 | ASCII..The prev| 00000160 69 6f 75 73 20 72 6f 75 74 69 6e 65 20 6f 6e 6c |ious routine onl| 00000170 79 20 61 6c 6c 6f 77 65 64 20 31 36 2d 62 69 74 |y allowed 16-bit| 00000180 20 6e 75 6d 62 65 72 73 20 28 6e 75 6d 62 65 72 | numbers (number| 00000190 73 20 69 6e 20 74 68 65 20 72 61 6e 67 65 0d 30 |s in the range.0| 000001a0 2d 36 35 35 33 35 29 20 74 6f 20 62 65 20 70 72 |-65535) to be pr| 000001b0 69 6e 74 65 64 2e 20 54 68 69 73 20 72 6f 75 74 |inted. This rout| 000001c0 69 6e 65 20 68 65 6c 70 73 20 79 6f 75 20 70 72 |ine helps you pr| 000001d0 69 6e 74 20 33 32 2d 62 69 74 20 6e 75 6d 62 65 |int 32-bit numbe| 000001e0 72 73 20 69 6e 0d 64 65 63 69 6d 61 6c 20 6f 72 |rs in.decimal or| 000001f0 20 68 65 78 2e 20 57 68 65 6e 20 77 65 20 73 70 | hex. When we sp| 00000200 65 61 6b 20 6f 66 20 22 68 65 78 61 64 65 63 69 |eak of "hexadeci| 00000210 6d 61 6c 22 20 6f 72 20 22 64 65 63 69 6d 61 6c |mal" or "decimal| 00000220 20 41 53 43 49 49 22 2c 20 69 74 0d 6d 65 61 6e | ASCII", it.mean| 00000230 73 20 74 68 61 74 20 61 20 73 74 72 69 6e 67 20 |s that a string | 00000240 63 6f 6e 74 61 69 6e 69 6e 67 20 41 53 43 49 49 |containing ASCII| 00000250 20 63 6f 64 65 73 20 69 73 20 6d 61 64 65 20 66 | codes is made f| 00000260 6f 72 20 74 68 65 20 67 69 76 65 6e 20 6e 75 6d |or the given num| 00000270 62 65 72 2e 0d 46 6f 72 20 65 78 61 6d 70 6c 65 |ber..For example| 00000280 2c 20 74 68 65 20 66 6f 75 72 20 41 53 43 49 49 |, the four ASCII| 00000290 20 64 65 63 69 6d 61 6c 20 63 6f 64 65 73 20 66 | decimal codes f| 000002a0 6f 72 20 26 39 45 46 46 20 61 72 65 20 35 37 2c |or &9EFF are 57,| 000002b0 20 36 39 2c 20 37 30 2c 20 61 6e 64 0d 37 30 20 | 69, 70, and.70 | 000002c0 28 69 67 6e 6f 72 69 6e 67 20 74 68 65 20 61 6d |(ignoring the am| 000002d0 70 65 72 73 61 6e 64 20 77 68 69 63 68 20 42 61 |persand which Ba| 000002e0 73 69 63 20 64 6f 65 73 6e 27 74 20 70 72 69 6e |sic doesn't prin| 000002f0 74 20 61 6e 79 77 61 79 29 2e 20 42 61 73 69 63 |t anyway). Basic| 00000300 20 70 75 74 73 0d 74 68 65 73 65 20 41 53 43 49 | puts.these ASCI| 00000310 49 20 63 6f 64 65 73 20 69 6e 74 6f 20 74 68 65 |I codes into the| 00000320 20 53 74 72 69 6e 67 20 57 6f 72 6b 20 41 72 65 | String Work Are| 00000330 61 2c 20 6f 72 20 53 57 41 20 66 6f 72 20 73 68 |a, or SWA for sh| 00000340 6f 72 74 2e 20 57 65 20 63 61 6e 20 0d 74 68 65 |ort. We can .the| 00000350 6e 20 75 73 65 20 61 6e 6f 74 68 65 72 20 72 6f |n use another ro| 00000360 75 74 69 6e 65 20 74 6f 20 70 72 69 6e 74 20 6f |utine to print o| 00000370 75 74 20 74 68 65 20 63 6f 6e 74 65 6e 74 73 20 |ut the contents | 00000380 6f 66 20 74 68 65 20 53 57 41 3a 0d 0d 37 2e 20 |of the SWA:..7. | 00000390 20 20 20 20 20 52 6f 75 74 69 6e 65 3a 20 50 72 | Routine: Pr| 000003a0 69 6e 74 20 74 68 65 20 53 57 41 0d 20 20 20 20 |int the SWA. | 000003b0 20 20 20 20 42 61 73 69 63 20 32 3a 20 26 38 45 | Basic 2: &8E| 000003c0 31 32 0d 20 20 20 20 20 20 20 20 42 61 73 69 63 |12. Basic| 000003d0 20 34 3a 20 26 39 32 31 42 0d 0d 20 20 20 20 20 | 4: &921B.. | 000003e0 20 20 20 45 6e 74 72 79 3a 20 6c 6f 63 61 74 69 | Entry: locati| 000003f0 6f 6e 20 26 33 30 20 6d 75 73 74 20 63 6f 6e 74 |on &30 must cont| 00000400 61 69 6e 20 74 68 65 20 6c 65 6e 67 74 68 20 6f |ain the length o| 00000410 66 20 74 68 65 20 73 74 72 69 6e 67 0d 20 20 20 |f the string. | 00000420 20 20 20 20 20 20 20 20 20 20 20 20 74 68 65 20 | the | 00000430 53 57 41 20 6d 75 73 74 20 63 6f 6e 74 61 69 6e |SWA must contain| 00000440 20 74 68 65 20 73 74 72 69 6e 67 0d 20 20 20 20 | the string. | 00000450 20 20 20 20 20 20 20 20 20 20 20 6c 6f 63 61 74 | locat| 00000460 69 6f 6e 20 26 41 20 6d 75 73 74 20 3d 20 30 2e |ion &A must = 0.| 00000470 0d 0d 20 20 20 20 20 20 20 20 45 78 2e 3a 20 20 |.. Ex.: | 00000480 20 20 4c 44 58 20 23 26 35 30 20 20 5c 63 6f 70 | LDX #&50 \cop| 00000490 79 20 69 6e 74 65 67 65 72 20 61 74 20 26 35 30 |y integer at &50| 000004a0 2d 33 0d 20 20 20 20 20 20 20 20 20 20 20 20 20 |-3. | 000004b0 20 20 20 4a 53 52 20 26 41 46 35 36 20 20 5c 74 | JSR &AF56 \t| 000004c0 6f 20 53 57 41 0d 20 20 20 20 20 20 20 20 20 20 |o SWA. | 000004d0 20 20 20 20 20 20 4c 44 41 20 23 26 46 46 3a 53 | LDA #&FF:S| 000004e0 54 41 20 26 31 35 20 20 5c 6e 75 6d 62 65 72 20 |TA &15 \number | 000004f0 74 6f 20 62 65 20 69 6e 20 68 65 78 0d 20 20 20 |to be in hex. | 00000500 20 20 20 20 20 20 20 20 20 20 20 20 20 4a 53 52 | JSR| 00000510 20 26 39 45 46 46 20 20 5c 63 6f 6e 76 65 72 74 | &9EFF \convert| 00000520 20 49 57 41 20 74 6f 20 41 53 43 49 49 20 63 6f | IWA to ASCII co| 00000530 64 65 73 20 20 0d 20 20 20 20 20 20 20 20 20 20 |des . | 00000540 20 20 20 20 20 20 4c 44 41 20 23 30 3a 53 54 41 | LDA #0:STA| 00000550 20 26 41 0d 20 20 20 20 20 20 20 20 20 20 20 20 | &A. | 00000560 20 20 20 20 4a 4d 50 20 26 38 45 31 32 20 20 5c | JMP &8E12 \| 00000570 61 6e 64 20 70 72 69 6e 74 20 74 68 65 20 6e 75 |and print the nu| 00000580 6d 62 65 72 20 0d 0d 38 2e 20 20 20 20 20 20 52 |mber ..8. R| 00000590 6f 75 74 69 6e 65 3a 20 52 61 6e 64 6f 6d 20 6e |outine: Random n| 000005a0 75 6d 62 65 72 20 67 65 6e 65 72 61 74 6f 72 0d |umber generator.| 000005b0 20 20 20 20 20 20 20 20 42 61 73 69 63 20 32 3a | Basic 2:| 000005c0 20 26 41 46 35 31 0d 20 20 20 20 20 20 20 20 42 | &AF51. B| 000005d0 61 73 69 63 20 34 3a 20 26 41 41 37 42 0d 20 20 |asic 4: &AA7B. | 000005e0 20 20 20 20 20 20 0d 20 20 20 20 20 20 20 20 4e | . N| 000005f0 6f 20 65 6e 74 72 79 20 72 65 71 75 69 72 65 6d |o entry requirem| 00000600 65 6e 74 73 2e 20 4f 6e 20 65 78 69 74 2c 20 74 |ents. On exit, t| 00000610 68 65 20 49 57 41 20 63 6f 6e 74 61 69 6e 73 20 |he IWA contains | 00000620 61 20 34 2d 62 79 74 65 20 72 61 6e 64 6f 6d 0d |a 4-byte random.| 00000630 20 20 20 20 20 20 20 20 69 6e 74 65 67 65 72 2e | integer.| 00000640 0d 0d 20 20 20 20 20 20 20 20 45 78 2e 3a 20 20 |.. Ex.: | 00000650 20 20 4a 53 52 20 26 41 46 35 31 0d 20 20 20 20 | JSR &AF51. | 00000660 20 20 20 20 20 20 20 20 20 20 20 20 4c 44 41 20 | LDA | 00000670 26 32 41 0d 20 20 20 20 20 20 20 20 20 20 20 20 |&2A. | 00000680 20 20 20 20 4a 53 52 20 61 6c 69 65 6e 0d 0d 49 | JSR alien..I| 00000690 20 66 69 6e 64 20 74 68 69 73 20 52 6f 6d 20 72 | find this Rom r| 000006a0 6f 75 74 69 6e 65 20 65 78 74 72 65 6d 65 6c 79 |outine extremely| 000006b0 20 75 73 65 66 75 6c 20 66 6f 72 20 67 65 74 74 | useful for gett| 000006c0 69 6e 67 20 72 61 6e 64 6f 6d 20 6e 75 6d 62 65 |ing random numbe| 000006d0 72 73 20 69 6e 0d 67 61 6d 65 73 2c 20 61 6e 64 |rs in.games, and| 000006e0 20 69 74 27 73 20 74 68 65 20 6f 6e 6c 79 20 64 | it's the only d| 000006f0 65 63 65 6e 74 20 77 61 79 20 6f 66 20 67 65 74 |ecent way of get| 00000700 74 69 6e 67 20 66 61 69 72 6c 79 20 75 6e 70 72 |ting fairly unpr| 00000710 65 64 69 63 74 61 62 6c 65 20 0d 6e 75 6d 62 65 |edictable .numbe| 00000720 72 73 20 69 6e 20 6d 61 63 68 69 6e 65 20 63 6f |rs in machine co| 00000730 64 65 2e 0d 20 0d 43 6f 6e 63 6c 75 73 69 6f 6e |de.. .Conclusion| 00000740 0d 49 46 20 79 6f 75 20 75 73 65 20 61 6e 79 20 |.IF you use any | 00000750 6f 66 20 74 68 65 20 61 62 6f 76 65 20 72 6f 75 |of the above rou| 00000760 74 69 6e 65 73 2c 20 64 6f 6e 27 74 20 66 6f 72 |tines, don't for| 00000770 67 65 74 20 74 6f 20 75 73 65 20 74 68 65 20 63 |get to use the c| 00000780 6f 72 72 65 63 74 0d 61 64 64 72 65 73 73 20 66 |orrect.address f| 00000790 6f 72 20 79 6f 75 72 20 76 65 72 73 69 6f 6e 20 |or your version | 000007a0 6f 66 20 42 61 73 69 63 2e 20 4e 6f 77 20 74 68 |of Basic. Now th| 000007b0 61 74 20 79 6f 75 27 76 65 20 73 65 65 6e 20 77 |at you've seen w| 000007c0 68 61 74 20 74 68 65 20 42 61 73 69 63 0d 52 6f |hat the Basic.Ro| 000007d0 6d 20 63 61 6e 20 64 6f 2c 20 68 6f 70 65 66 75 |m can do, hopefu| 000007e0 6c 6c 79 20 79 6f 75 27 6c 6c 20 77 61 6e 74 20 |lly you'll want | 000007f0 74 6f 20 73 74 61 72 74 20 65 78 70 6c 6f 72 69 |to start explori| 00000800 6e 67 20 6f 74 68 65 72 20 70 61 72 74 73 2e 20 |ng other parts. | 00000810 49 66 20 79 6f 75 0d 66 69 6e 64 20 61 6e 79 74 |If you.find anyt| 00000820 68 69 6e 67 20 75 73 65 66 75 6c 2c 20 64 6f 20 |hing useful, do | 00000830 77 72 69 74 65 20 69 6e 20 61 6e 64 20 6c 65 74 |write in and let| 00000840 20 75 73 20 6b 6e 6f 77 21 0d 20 20 20 20 20 20 | us know!. | 00000850 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | * 00000870 20 20 20 20 20 20 20 20 20 20 20 20 20 20 43 68 | Ch| 00000880 72 69 73 74 6f 70 68 65 72 20 44 65 77 68 75 72 |ristopher Dewhur| 00000890 73 74 0d 20 20 20 20 20 20 20 20 20 20 20 20 20 |st. | 000008a0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | * 000008c0 20 20 20 20 20 20 20 20 20 32 34 20 53 65 70 74 | 24 Sept| 000008d0 65 6d 62 65 72 2c 20 32 30 30 30 0d 20 20 20 20 |ember, 2000. | 000008e0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | * 00000910 20 20 20 20 20 20 20 20 20 20 20 20 20 45 55 47 | EUG| 00000920 20 23 35 35 0d | #55.| 00000925
V/+BRR3.m0
V/+BRR3.m1
V/+BRR3.m2
V/+BRR3.m4
V/+BRR3.m5
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