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13_11_87/T\SWR04
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 » CEEFAX disks » telesoftware3.adl |
| Filename: | 13_11_87/T\SWR04 |
| Read OK: | ✔ |
| File size: | 2278 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
Duplicates
There is 1 duplicate copy of this file in the archive:
- CEEFAX disks » telesoftware3.adl » 13_11_87/T\SWR04
- CEEFAX disks » telesoftware8.adl » 30-07-88/T\SWR04
File contents
Mastering Sideways ROM & RAM - Module 04 - Using *ENABLE
--------------------------------------------------------
In this module I will show you how to use the *ENABLE checker
provided in the Acorn 0.90 DFS. This technique can be adapted for use
in your own sideways ram programs with either DFS 0.90 or DFS 1.20.
The DFS provides a disc-specific operating system control functions
support (Osfsc) which you can use from your own machine code programs.
Osfsc is vectored by the filing system control vector (FSCV) at &21E
to &FF2A, which switches to the DFS rom and uses the extended FSCV
vector at &DCC to access the DFS.
Osfsc does not have a direct entry address only an indirect entry at
&21E. The accumulator on entry to Osfsc contains a code defining the
action to be performed. Osfsc called with A=8 (X and Y undefined) is
used by the DFS to implement a protection mechanism on dangerous
commands by insisting that the previous command was *ENABLE.
Acorn DFS 0.90 has a DFS Enable flag at &10C8. It can have one of
three values shown in figure 4.1
&10C8 Meaning
----------------------------------------------------------
&FF No record of *ENABLE, flag disabled.
&00 Flag on its way from &01 to &FF, flag transitory.
&01 *ENABLE was the last command, flag enabled.
Figure 4.1 The Enable flag at &10C8 (DFS 0.90)
----------------------------------------------
Osfsc sets the negative flag if *ENABLE was not the last command. It
also resets the enable flag as shown in figure 4.2
Before call After call N flag
--------------------------------
&FF &FF 1
&00 &FF 1
&01 &00 0
Figure 4.2 The Enable and Negative flags after *ENABLE
------------------------------------------------------
It can be seen from figure 4.2 that calling Osfsc with A=8 switches
the enable flag from an enabled state (&01) to a transitory state
(&00) and then to a disabled state (&FF). It can also test for *ENABLE
as the previous command (negative flag clear). You will see later in
the module that the transitory state can be used to test for *ENABLE
from sideways ram service utilities but calling Osfsc and testing the
negative flag is the "legal" way to test for *ENABLE from user memory.
Not all DFS roms fully implement Osfsc with A=8. Acorn DFS 1.20 does
not and DFS roms from manufacturers other than Acorn may not implement
it in the way demonstrated. You can use the program ENABTST to test
your DFS rom. ENABTST must run in the I/O processor.
Load ENABTST into memory and run the program. It should respond with
"Not enabled at line 230". Type *ENABLE, press Return and run the
program again. If your DFS implements an enable checker the program
will respond with "Enabled at line 230", if the DFS does not implement
an enable checker the program will again respond with "Not enabled at
line 230". If the program responded with the enabled message run it a
third time. If the enable checker works properly the program will go
back to the not enabled message. This test program will show that the
enable checker, if it has been properly implemented in the DFS, will
only indicate an enabled state if *ENABLE was the previous command.
10 REM: ENABTST
20 DIM mcode &100
30 fscv=&21E
40 FOR pass=0 TO 2 STEP 2
50 P%=mcode
60 [ OPT pass
70 .test
80 LDA #8
90 JSR osfsc
100 BPL enabled
110 BRK
120 BRK
130 OPT FNequs("Not enabled")
140 .enabled
150 BRK
160 BRK
170 OPT FNequs("Enabled")
180 BRK
190 .osfsc
200 JMP (fscv)
210 ]
220 NEXT
230 CALL test
240 END
250 DEFFNequs(string$)
260 $P%=string$
270 P%=P%+LEN(string$)
280 =pass
The program ENABTST demonstrates the legal use of Osfsc. It should
be called by jumping to a subroutine where the only instruction is an
indirect jump using FSCV, ie. JMP(&21E). Osfsc cannot be used in this
way in a sideways ram program because using a * command to call your
utility will reset the enable flag into its transitory state before
Osfsc has the chance to test it. As you have seen in figure 4.2 Osfsc
cannot distinguish between the transitory state and the disabled state
using the negative flag. In order to use *ENABLE in your own SWR
software you have to cheat by peeking the enable flag directly and
then use the transitory state, when it is on its way from &01 to &FF,
to indicate an enabled state. The flag at &10C8 (&10C7 in DFS 1.20)
will equal zero in the transitory state and this is used to indicate
to SWR software that *ENABLE was the previous command.
This technique is demonstrated in the program ENABLE which can be
used with either Acorn DFS 0.90 or 1.20 by choosing the appropriate
address for the enable flag in line 90. Remember that this makes the
program DFS specific. If you intend to use this technique you must
specify which DFS is to be used with your programs.
The program ENABLE uses a "dangerous" routine to reset the computer
and is protected using the *ENABLE command. To show yourself how the
reset works first find the reset address for your computer's operating
system. To find it from BASIC type PRINT ~ !-4 and press Return. With
MOS 1.20 you will get the following result:
>PRINT ~ !-4
DC1CD9CD
>
This prints the hexadecimal values of the 4 bytes at the top of the
memory map. The reset address is in bytes &FFFC (low byte) and &FFFD
(high byte), in this example the low byte is &CD and the high byte is
&D9. The reset address is &D9CD. To reset the BBC B with MOS 1.20
type:
>*FX 151,78,127
>CALL &D9CD
This will reset the computer and clear the user memory. The value of
protecting such a dangerous routine from careless use should be
obvious.
ENABLE uses a similar header and interpreter to the SWR software
used to illustrate Module 3. The title string, and therefore the
command string, is "RESET". To use the program load the object code it
generates into sideways ram and press Break. Then type *ENABLE and
Return followed by *RESET and Return.
The enable checker is in lines 600 and 610. If the number stored in
the enable flag is &00 control is passes to the reset routine starting
at line 670. If the enable flag stores any number other than zero the
registers are pulled off the stack and control is passed back to the
MOS with A=0 (lines 620-650). The registers are not pulled off the
stack by the reset routine (lines 680-720) because reseting the
computer in this way also resets the stack pointer.
10 REM: ENABLE
20 MODE7
30 HIMEM=&3C00
40 DIM save 50
50 diff=&8000-HIMEM
60 comvec=&F2
70 REM: DFS 1.20 enabflag=&10C7
80 REM: DFS 0.90 enabflag=&10C8
90 enabflag=&10C8
100 gsread=&FFC5
110 osbyte=&FFF4
120 oscli=&FFF7
130 reset=&FFFC
140 FOR pass = 0 TO 2 STEP 2
150 P%=HIMEM
160 [ OPT pass
170 BRK
180 BRK
190 BRK
200 JMP service+diff
210 OPT FNequb(&82)
220 OPT FNequb((copyright+diff) MOD 256)
230 BRK
240 .title
250 OPT FNequs("RESET")
260 .copyright
270 BRK
280 OPT FNequs("(C) Gordon Horsington 1987")
290 BRK
300 .service
310 CMP #4
320 BEQ unrecognised
330 RTS
340 .unrecognised
350 PHA
360 TXA
370 PHA
380 TYA
390 PHA
400 LDX #&FF
410 .comloop
420 INX
430 LDA title+diff,X
440 BEQ found
450 LDA (comvec),Y
460 INY
470 CMP #ASC(".")
480 BEQ found
490 AND #&DF
500 CMP title+diff,X
510 BEQ comloop
520 .finish
530 PLA
540 TAY
550 PLA
560 TAX
570 PLA
580 RTS
590 .found
600 LDA enabflag
610 BEQ enabled \ Flag going from &01 to &FF
620 PLA
630 PLA
640 PLA
650 LDA #0
660 RTS
670 .enabled
680 LDA #&97
690 LDX #&4E
700 LDY #&7F
710 JSR osbyte \ *FX151,78,127
720 JMP (reset)
730 .lastbyte
740 ]
750 NEXT
760 INPUT'"Save filename = "filename$
770 IF filename$="" END
780 $save="SAVE "+filename$+" "+STR$~(HIMEM)+" "+STR$~(las
tbyte)+" FFFF8000 FFFF8000"
790 X%=save MOD 256
800 Y%=save DIV 256
810 *OPT1,2
820 CALL oscli
830 *OPT1,0
840 END
850 DEFFNequb(byte)
860 ?P%=byte
870 P%=P%+1
880 =pass
890 DEFFNequw(word)
900 ?P%=word MOD 256
910 P%?1=word DIV 256
920 P%=P%+2
930 =pass
940 DEFFNequd(double)
950 !P%=double
960 P%=P%+4
970 =pass
980 DEFFNequs(string$)
990 $P%=string$
1000 P%=P%+LEN(string$)
1010 =pass
00000000 4d 61 73 74 65 72 69 6e 67 20 53 69 64 65 77 61 |Mastering Sidewa|
00000010 79 73 20 52 4f 4d 20 26 20 52 41 4d 20 2d 20 4d |ys ROM & RAM - M|
00000020 6f 64 75 6c 65 20 30 34 20 2d 20 55 73 69 6e 67 |odule 04 - Using|
00000030 20 2a 45 4e 41 42 4c 45 0d 2d 2d 2d 2d 2d 2d 2d | *ENABLE.-------|
00000040 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
00000070 2d 0d 0d 20 20 49 6e 20 74 68 69 73 20 6d 6f 64 |-.. In this mod|
00000080 75 6c 65 20 49 20 77 69 6c 6c 20 73 68 6f 77 20 |ule I will show |
00000090 79 6f 75 20 68 6f 77 20 74 6f 20 75 73 65 20 74 |you how to use t|
000000a0 68 65 20 2a 45 4e 41 42 4c 45 20 63 68 65 63 6b |he *ENABLE check|
000000b0 65 72 0d 70 72 6f 76 69 64 65 64 20 69 6e 20 74 |er.provided in t|
000000c0 68 65 20 41 63 6f 72 6e 20 30 2e 39 30 20 44 46 |he Acorn 0.90 DF|
000000d0 53 2e 20 54 68 69 73 20 74 65 63 68 6e 69 71 75 |S. This techniqu|
000000e0 65 20 63 61 6e 20 62 65 20 61 64 61 70 74 65 64 |e can be adapted|
000000f0 20 66 6f 72 20 75 73 65 0d 69 6e 20 79 6f 75 72 | for use.in your|
00000100 20 6f 77 6e 20 73 69 64 65 77 61 79 73 20 72 61 | own sideways ra|
00000110 6d 20 70 72 6f 67 72 61 6d 73 20 77 69 74 68 20 |m programs with |
00000120 65 69 74 68 65 72 20 44 46 53 20 30 2e 39 30 20 |either DFS 0.90 |
00000130 6f 72 20 44 46 53 20 31 2e 32 30 2e 0d 0d 20 20 |or DFS 1.20... |
00000140 54 68 65 20 44 46 53 20 70 72 6f 76 69 64 65 73 |The DFS provides|
00000150 20 61 20 64 69 73 63 2d 73 70 65 63 69 66 69 63 | a disc-specific|
00000160 20 6f 70 65 72 61 74 69 6e 67 20 73 79 73 74 65 | operating syste|
00000170 6d 20 63 6f 6e 74 72 6f 6c 20 66 75 6e 63 74 69 |m control functi|
00000180 6f 6e 73 0d 73 75 70 70 6f 72 74 20 28 4f 73 66 |ons.support (Osf|
00000190 73 63 29 20 77 68 69 63 68 20 79 6f 75 20 63 61 |sc) which you ca|
000001a0 6e 20 75 73 65 20 66 72 6f 6d 20 79 6f 75 72 20 |n use from your |
000001b0 6f 77 6e 20 6d 61 63 68 69 6e 65 20 63 6f 64 65 |own machine code|
000001c0 20 70 72 6f 67 72 61 6d 73 2e 0d 4f 73 66 73 63 | programs..Osfsc|
000001d0 20 69 73 20 76 65 63 74 6f 72 65 64 20 62 79 20 | is vectored by |
000001e0 74 68 65 20 66 69 6c 69 6e 67 20 73 79 73 74 65 |the filing syste|
000001f0 6d 20 63 6f 6e 74 72 6f 6c 20 76 65 63 74 6f 72 |m control vector|
00000200 20 28 46 53 43 56 29 20 61 74 20 26 32 31 45 0d | (FSCV) at &21E.|
00000210 74 6f 20 26 46 46 32 41 2c 20 77 68 69 63 68 20 |to &FF2A, which |
00000220 73 77 69 74 63 68 65 73 20 74 6f 20 74 68 65 20 |switches to the |
00000230 44 46 53 20 72 6f 6d 20 61 6e 64 20 75 73 65 73 |DFS rom and uses|
00000240 20 74 68 65 20 65 78 74 65 6e 64 65 64 20 46 53 | the extended FS|
00000250 43 56 0d 76 65 63 74 6f 72 20 61 74 20 26 44 43 |CV.vector at &DC|
00000260 43 20 74 6f 20 61 63 63 65 73 73 20 74 68 65 20 |C to access the |
00000270 44 46 53 2e 0d 0d 20 20 4f 73 66 73 63 20 64 6f |DFS... Osfsc do|
00000280 65 73 20 6e 6f 74 20 68 61 76 65 20 61 20 64 69 |es not have a di|
00000290 72 65 63 74 20 65 6e 74 72 79 20 61 64 64 72 65 |rect entry addre|
000002a0 73 73 20 6f 6e 6c 79 20 61 6e 20 69 6e 64 69 72 |ss only an indir|
000002b0 65 63 74 20 65 6e 74 72 79 20 61 74 0d 26 32 31 |ect entry at.&21|
000002c0 45 2e 20 54 68 65 20 61 63 63 75 6d 75 6c 61 74 |E. The accumulat|
000002d0 6f 72 20 6f 6e 20 65 6e 74 72 79 20 74 6f 20 4f |or on entry to O|
000002e0 73 66 73 63 20 63 6f 6e 74 61 69 6e 73 20 61 20 |sfsc contains a |
000002f0 63 6f 64 65 20 64 65 66 69 6e 69 6e 67 20 74 68 |code defining th|
00000300 65 0d 61 63 74 69 6f 6e 20 74 6f 20 62 65 20 70 |e.action to be p|
00000310 65 72 66 6f 72 6d 65 64 2e 20 4f 73 66 73 63 20 |erformed. Osfsc |
00000320 63 61 6c 6c 65 64 20 77 69 74 68 20 41 3d 38 20 |called with A=8 |
00000330 28 58 20 61 6e 64 20 59 20 75 6e 64 65 66 69 6e |(X and Y undefin|
00000340 65 64 29 20 69 73 0d 75 73 65 64 20 62 79 20 74 |ed) is.used by t|
00000350 68 65 20 44 46 53 20 74 6f 20 69 6d 70 6c 65 6d |he DFS to implem|
00000360 65 6e 74 20 61 20 70 72 6f 74 65 63 74 69 6f 6e |ent a protection|
00000370 20 6d 65 63 68 61 6e 69 73 6d 20 6f 6e 20 64 61 | mechanism on da|
00000380 6e 67 65 72 6f 75 73 0d 63 6f 6d 6d 61 6e 64 73 |ngerous.commands|
00000390 20 62 79 20 69 6e 73 69 73 74 69 6e 67 20 74 68 | by insisting th|
000003a0 61 74 20 74 68 65 20 70 72 65 76 69 6f 75 73 20 |at the previous |
000003b0 63 6f 6d 6d 61 6e 64 20 77 61 73 20 2a 45 4e 41 |command was *ENA|
000003c0 42 4c 45 2e 0d 0d 20 20 41 63 6f 72 6e 20 44 46 |BLE... Acorn DF|
000003d0 53 20 30 2e 39 30 20 68 61 73 20 61 20 44 46 53 |S 0.90 has a DFS|
000003e0 20 45 6e 61 62 6c 65 20 66 6c 61 67 20 61 74 20 | Enable flag at |
000003f0 26 31 30 43 38 2e 20 49 74 20 63 61 6e 20 68 61 |&10C8. It can ha|
00000400 76 65 20 6f 6e 65 20 6f 66 0d 74 68 72 65 65 20 |ve one of.three |
00000410 76 61 6c 75 65 73 20 73 68 6f 77 6e 20 69 6e 20 |values shown in |
00000420 66 69 67 75 72 65 20 34 2e 31 0d 0d 0d 0d 0d 26 |figure 4.1.....&|
00000430 31 30 43 38 20 20 20 20 4d 65 61 6e 69 6e 67 0d |10C8 Meaning.|
00000440 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
00000470 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 0d 26 46 46 20 20 |----------.&FF |
00000480 20 20 20 20 4e 6f 20 72 65 63 6f 72 64 20 6f 66 | No record of|
00000490 20 2a 45 4e 41 42 4c 45 2c 20 66 6c 61 67 20 64 | *ENABLE, flag d|
000004a0 69 73 61 62 6c 65 64 2e 0d 26 30 30 20 20 20 20 |isabled..&00 |
000004b0 20 20 46 6c 61 67 20 6f 6e 20 69 74 73 20 77 61 | Flag on its wa|
000004c0 79 20 66 72 6f 6d 20 26 30 31 20 74 6f 20 26 46 |y from &01 to &F|
000004d0 46 2c 20 66 6c 61 67 20 74 72 61 6e 73 69 74 6f |F, flag transito|
000004e0 72 79 2e 0d 26 30 31 20 20 20 20 20 20 2a 45 4e |ry..&01 *EN|
000004f0 41 42 4c 45 20 77 61 73 20 74 68 65 20 6c 61 73 |ABLE was the las|
00000500 74 20 63 6f 6d 6d 61 6e 64 2c 20 66 6c 61 67 20 |t command, flag |
00000510 65 6e 61 62 6c 65 64 2e 0d 0d 46 69 67 75 72 65 |enabled...Figure|
00000520 20 34 2e 31 20 54 68 65 20 45 6e 61 62 6c 65 20 | 4.1 The Enable |
00000530 66 6c 61 67 20 61 74 20 26 31 30 43 38 20 28 44 |flag at &10C8 (D|
00000540 46 53 20 30 2e 39 30 29 0d 2d 2d 2d 2d 2d 2d 2d |FS 0.90).-------|
00000550 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
00000570 2d 2d 2d 2d 2d 2d 2d 0d 0d 0d 0d 0d 20 20 4f 73 |-------..... Os|
00000580 66 73 63 20 73 65 74 73 20 74 68 65 20 6e 65 67 |fsc sets the neg|
00000590 61 74 69 76 65 20 66 6c 61 67 20 69 66 20 2a 45 |ative flag if *E|
000005a0 4e 41 42 4c 45 20 77 61 73 20 6e 6f 74 20 74 68 |NABLE was not th|
000005b0 65 20 6c 61 73 74 20 63 6f 6d 6d 61 6e 64 2e 20 |e last command. |
000005c0 49 74 0d 61 6c 73 6f 20 72 65 73 65 74 73 20 74 |It.also resets t|
000005d0 68 65 20 65 6e 61 62 6c 65 20 66 6c 61 67 20 61 |he enable flag a|
000005e0 73 20 73 68 6f 77 6e 20 69 6e 20 66 69 67 75 72 |s shown in figur|
000005f0 65 20 34 2e 32 0d 0d 0d 0d 0d 42 65 66 6f 72 65 |e 4.2.....Before|
00000600 20 63 61 6c 6c 20 20 20 41 66 74 65 72 20 63 61 | call After ca|
00000610 6c 6c 20 20 20 4e 20 66 6c 61 67 0d 2d 2d 2d 2d |ll N flag.----|
00000620 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
00000630 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 0d 20 20 20 |------------. |
00000640 26 46 46 20 20 20 20 20 20 20 20 20 20 20 26 46 |&FF &F|
00000650 46 20 20 20 20 20 20 20 20 20 31 0d 20 20 20 26 |F 1. &|
00000660 30 30 20 20 20 20 20 20 20 20 20 20 20 26 46 46 |00 &FF|
00000670 20 20 20 20 20 20 20 20 20 31 0d 20 20 20 26 30 | 1. &0|
00000680 31 20 20 20 20 20 20 20 20 20 20 20 26 30 30 20 |1 &00 |
00000690 20 20 20 20 20 20 20 20 30 0d 0d 46 69 67 75 72 | 0..Figur|
000006a0 65 20 34 2e 32 20 54 68 65 20 45 6e 61 62 6c 65 |e 4.2 The Enable|
000006b0 20 61 6e 64 20 4e 65 67 61 74 69 76 65 20 66 6c | and Negative fl|
000006c0 61 67 73 20 61 66 74 65 72 20 2a 45 4e 41 42 4c |ags after *ENABL|
000006d0 45 0d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |E.--------------|
000006e0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
00000700 2d 2d 2d 2d 2d 2d 2d 2d 0d 0d 0d 0d 0d 20 20 49 |--------..... I|
00000710 74 20 63 61 6e 20 62 65 20 73 65 65 6e 20 66 72 |t can be seen fr|
00000720 6f 6d 20 66 69 67 75 72 65 20 34 2e 32 20 74 68 |om figure 4.2 th|
00000730 61 74 20 63 61 6c 6c 69 6e 67 20 4f 73 66 73 63 |at calling Osfsc|
00000740 20 77 69 74 68 20 41 3d 38 20 73 77 69 74 63 68 | with A=8 switch|
00000750 65 73 0d 74 68 65 20 65 6e 61 62 6c 65 20 66 6c |es.the enable fl|
00000760 61 67 20 66 72 6f 6d 20 61 6e 20 65 6e 61 62 6c |ag from an enabl|
00000770 65 64 20 73 74 61 74 65 20 28 26 30 31 29 20 74 |ed state (&01) t|
00000780 6f 20 61 20 74 72 61 6e 73 69 74 6f 72 79 20 73 |o a transitory s|
00000790 74 61 74 65 0d 28 26 30 30 29 20 61 6e 64 20 74 |tate.(&00) and t|
000007a0 68 65 6e 20 74 6f 20 61 20 64 69 73 61 62 6c 65 |hen to a disable|
000007b0 64 20 73 74 61 74 65 20 28 26 46 46 29 2e 20 49 |d state (&FF). I|
000007c0 74 20 63 61 6e 20 61 6c 73 6f 20 74 65 73 74 20 |t can also test |
000007d0 66 6f 72 20 2a 45 4e 41 42 4c 45 0d 61 73 20 74 |for *ENABLE.as t|
000007e0 68 65 20 70 72 65 76 69 6f 75 73 20 63 6f 6d 6d |he previous comm|
000007f0 61 6e 64 20 28 6e 65 67 61 74 69 76 65 20 66 6c |and (negative fl|
00000800 61 67 20 63 6c 65 61 72 29 2e 20 59 6f 75 20 77 |ag clear). You w|
00000810 69 6c 6c 20 73 65 65 20 6c 61 74 65 72 20 69 6e |ill see later in|
00000820 0d 74 68 65 20 6d 6f 64 75 6c 65 20 74 68 61 74 |.the module that|
00000830 20 74 68 65 20 74 72 61 6e 73 69 74 6f 72 79 20 | the transitory |
00000840 73 74 61 74 65 20 63 61 6e 20 62 65 20 75 73 65 |state can be use|
00000850 64 20 74 6f 20 74 65 73 74 20 66 6f 72 20 2a 45 |d to test for *E|
00000860 4e 41 42 4c 45 0d 66 72 6f 6d 20 73 69 64 65 77 |NABLE.from sidew|
00000870 61 79 73 20 72 61 6d 20 73 65 72 76 69 63 65 20 |ays ram service |
00000880 75 74 69 6c 69 74 69 65 73 20 62 75 74 20 63 61 |utilities but ca|
00000890 6c 6c 69 6e 67 20 4f 73 66 73 63 20 61 6e 64 20 |lling Osfsc and |
000008a0 74 65 73 74 69 6e 67 20 74 68 65 0d 6e 65 67 61 |testing the.nega|
000008b0 74 69 76 65 20 66 6c 61 67 20 69 73 20 74 68 65 |tive flag is the|
000008c0 20 22 6c 65 67 61 6c 22 20 77 61 79 20 74 6f 20 | "legal" way to |
000008d0 74 65 73 74 20 66 6f 72 20 2a 45 4e 41 42 4c 45 |test for *ENABLE|
000008e0 20 66 72 6f 6d 20 75 73 65 72 20 6d 65 6d 6f 72 | from user memor|
000008f0 79 2e 0d 0d 20 20 4e 6f 74 20 61 6c 6c 20 44 46 |y... Not all DF|
00000900 53 20 72 6f 6d 73 20 66 75 6c 6c 79 20 69 6d 70 |S roms fully imp|
00000910 6c 65 6d 65 6e 74 20 4f 73 66 73 63 20 77 69 74 |lement Osfsc wit|
00000920 68 20 41 3d 38 2e 20 41 63 6f 72 6e 20 44 46 53 |h A=8. Acorn DFS|
00000930 20 31 2e 32 30 20 64 6f 65 73 0d 6e 6f 74 20 61 | 1.20 does.not a|
00000940 6e 64 20 44 46 53 20 72 6f 6d 73 20 66 72 6f 6d |nd DFS roms from|
00000950 20 6d 61 6e 75 66 61 63 74 75 72 65 72 73 20 6f | manufacturers o|
00000960 74 68 65 72 20 74 68 61 6e 20 41 63 6f 72 6e 20 |ther than Acorn |
00000970 6d 61 79 20 6e 6f 74 20 69 6d 70 6c 65 6d 65 6e |may not implemen|
00000980 74 0d 69 74 20 69 6e 20 74 68 65 20 77 61 79 20 |t.it in the way |
00000990 64 65 6d 6f 6e 73 74 72 61 74 65 64 2e 20 59 6f |demonstrated. Yo|
000009a0 75 20 63 61 6e 20 75 73 65 20 74 68 65 20 70 72 |u can use the pr|
000009b0 6f 67 72 61 6d 20 45 4e 41 42 54 53 54 20 74 6f |ogram ENABTST to|
000009c0 20 74 65 73 74 0d 79 6f 75 72 20 44 46 53 20 72 | test.your DFS r|
000009d0 6f 6d 2e 20 45 4e 41 42 54 53 54 20 6d 75 73 74 |om. ENABTST must|
000009e0 20 72 75 6e 20 69 6e 20 74 68 65 20 49 2f 4f 20 | run in the I/O |
000009f0 70 72 6f 63 65 73 73 6f 72 2e 0d 0d 20 20 4c 6f |processor... Lo|
00000a00 61 64 20 45 4e 41 42 54 53 54 20 69 6e 74 6f 20 |ad ENABTST into |
00000a10 6d 65 6d 6f 72 79 20 61 6e 64 20 72 75 6e 20 74 |memory and run t|
00000a20 68 65 20 70 72 6f 67 72 61 6d 2e 20 49 74 20 73 |he program. It s|
00000a30 68 6f 75 6c 64 20 72 65 73 70 6f 6e 64 20 77 69 |hould respond wi|
00000a40 74 68 0d 22 4e 6f 74 20 65 6e 61 62 6c 65 64 20 |th."Not enabled |
00000a50 61 74 20 6c 69 6e 65 20 32 33 30 22 2e 20 54 79 |at line 230". Ty|
00000a60 70 65 20 2a 45 4e 41 42 4c 45 2c 20 70 72 65 73 |pe *ENABLE, pres|
00000a70 73 20 52 65 74 75 72 6e 20 61 6e 64 20 72 75 6e |s Return and run|
00000a80 20 74 68 65 0d 70 72 6f 67 72 61 6d 20 61 67 61 | the.program aga|
00000a90 69 6e 2e 20 49 66 20 79 6f 75 72 20 44 46 53 20 |in. If your DFS |
00000aa0 69 6d 70 6c 65 6d 65 6e 74 73 20 61 6e 20 65 6e |implements an en|
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00001b10 20 70 61 73 73 0d 20 20 31 37 30 20 20 20 20 20 | pass. 170 |
00001b20 20 20 20 20 42 52 4b 0d 20 20 31 38 30 20 20 20 | BRK. 180 |
00001b30 20 20 20 20 20 20 42 52 4b 0d 20 20 31 39 30 20 | BRK. 190 |
00001b40 20 20 20 20 20 20 20 20 42 52 4b 0d 20 20 32 30 | BRK. 20|
00001b50 30 20 20 20 20 20 20 20 20 20 4a 4d 50 20 73 65 |0 JMP se|
00001b60 72 76 69 63 65 2b 64 69 66 66 0d 20 20 32 31 30 |rvice+diff. 210|
00001b70 20 20 20 20 20 20 20 20 20 4f 50 54 20 46 4e 65 | OPT FNe|
00001b80 71 75 62 28 26 38 32 29 0d 20 20 32 32 30 20 20 |qub(&82). 220 |
00001b90 20 20 20 20 20 20 20 4f 50 54 20 46 4e 65 71 75 | OPT FNequ|
00001ba0 62 28 28 63 6f 70 79 72 69 67 68 74 2b 64 69 66 |b((copyright+dif|
00001bb0 66 29 20 4d 4f 44 20 32 35 36 29 0d 20 20 32 33 |f) MOD 256). 23|
00001bc0 30 20 20 20 20 20 20 20 20 20 42 52 4b 0d 20 20 |0 BRK. |
00001bd0 32 34 30 20 2e 74 69 74 6c 65 0d 20 20 32 35 30 |240 .title. 250|
00001be0 20 20 20 20 20 20 20 20 20 4f 50 54 20 46 4e 65 | OPT FNe|
00001bf0 71 75 73 28 22 52 45 53 45 54 22 29 0d 20 20 32 |qus("RESET"). 2|
00001c00 36 30 20 2e 63 6f 70 79 72 69 67 68 74 0d 20 20 |60 .copyright. |
00001c10 32 37 30 20 20 20 20 20 20 20 20 20 42 52 4b 0d |270 BRK.|
00001c20 20 20 32 38 30 20 20 20 20 20 20 20 20 20 4f 50 | 280 OP|
00001c30 54 20 46 4e 65 71 75 73 28 22 28 43 29 20 47 6f |T FNequs("(C) Go|
00001c40 72 64 6f 6e 20 48 6f 72 73 69 6e 67 74 6f 6e 20 |rdon Horsington |
00001c50 31 39 38 37 22 29 0d 20 20 32 39 30 20 20 20 20 |1987"). 290 |
00001c60 20 20 20 20 20 42 52 4b 0d 20 20 33 30 30 20 2e | BRK. 300 .|
00001c70 73 65 72 76 69 63 65 0d 20 20 33 31 30 20 20 20 |service. 310 |
00001c80 20 20 20 20 20 20 43 4d 50 20 23 34 0d 20 20 33 | CMP #4. 3|
00001c90 32 30 20 20 20 20 20 20 20 20 20 42 45 51 20 75 |20 BEQ u|
00001ca0 6e 72 65 63 6f 67 6e 69 73 65 64 0d 20 20 33 33 |nrecognised. 33|
00001cb0 30 20 20 20 20 20 20 20 20 20 52 54 53 0d 20 20 |0 RTS. |
00001cc0 33 34 30 20 2e 75 6e 72 65 63 6f 67 6e 69 73 65 |340 .unrecognise|
00001cd0 64 0d 20 20 33 35 30 20 20 20 20 20 20 20 20 20 |d. 350 |
00001ce0 50 48 41 0d 20 20 33 36 30 20 20 20 20 20 20 20 |PHA. 360 |
00001cf0 20 20 54 58 41 0d 20 20 33 37 30 20 20 20 20 20 | TXA. 370 |
00001d00 20 20 20 20 50 48 41 0d 20 20 33 38 30 20 20 20 | PHA. 380 |
00001d10 20 20 20 20 20 20 54 59 41 0d 20 20 33 39 30 20 | TYA. 390 |
00001d20 20 20 20 20 20 20 20 20 50 48 41 0d 20 20 34 30 | PHA. 40|
00001d30 30 20 20 20 20 20 20 20 20 20 4c 44 58 20 23 26 |0 LDX #&|
00001d40 46 46 0d 20 20 34 31 30 20 2e 63 6f 6d 6c 6f 6f |FF. 410 .comloo|
00001d50 70 0d 20 20 34 32 30 20 20 20 20 20 20 20 20 20 |p. 420 |
00001d60 49 4e 58 0d 20 20 34 33 30 20 20 20 20 20 20 20 |INX. 430 |
00001d70 20 20 4c 44 41 20 74 69 74 6c 65 2b 64 69 66 66 | LDA title+diff|
00001d80 2c 58 0d 20 20 34 34 30 20 20 20 20 20 20 20 20 |,X. 440 |
00001d90 20 42 45 51 20 66 6f 75 6e 64 0d 20 20 34 35 30 | BEQ found. 450|
00001da0 20 20 20 20 20 20 20 20 20 4c 44 41 20 28 63 6f | LDA (co|
00001db0 6d 76 65 63 29 2c 59 0d 20 20 34 36 30 20 20 20 |mvec),Y. 460 |
00001dc0 20 20 20 20 20 20 49 4e 59 0d 20 20 34 37 30 20 | INY. 470 |
00001dd0 20 20 20 20 20 20 20 20 43 4d 50 20 23 41 53 43 | CMP #ASC|
00001de0 28 22 2e 22 29 0d 20 20 34 38 30 20 20 20 20 20 |("."). 480 |
00001df0 20 20 20 20 42 45 51 20 66 6f 75 6e 64 0d 20 20 | BEQ found. |
00001e00 34 39 30 20 20 20 20 20 20 20 20 20 41 4e 44 20 |490 AND |
00001e10 23 26 44 46 0d 20 20 35 30 30 20 20 20 20 20 20 |#&DF. 500 |
00001e20 20 20 20 43 4d 50 20 74 69 74 6c 65 2b 64 69 66 | CMP title+dif|
00001e30 66 2c 58 0d 20 20 35 31 30 20 20 20 20 20 20 20 |f,X. 510 |
00001e40 20 20 42 45 51 20 63 6f 6d 6c 6f 6f 70 0d 20 20 | BEQ comloop. |
00001e50 35 32 30 20 2e 66 69 6e 69 73 68 0d 20 20 35 33 |520 .finish. 53|
00001e60 30 20 20 20 20 20 20 20 20 20 50 4c 41 0d 20 20 |0 PLA. |
00001e70 35 34 30 20 20 20 20 20 20 20 20 20 54 41 59 0d |540 TAY.|
00001e80 20 20 35 35 30 20 20 20 20 20 20 20 20 20 50 4c | 550 PL|
00001e90 41 0d 20 20 35 36 30 20 20 20 20 20 20 20 20 20 |A. 560 |
00001ea0 54 41 58 0d 20 20 35 37 30 20 20 20 20 20 20 20 |TAX. 570 |
00001eb0 20 20 50 4c 41 0d 20 20 35 38 30 20 20 20 20 20 | PLA. 580 |
00001ec0 20 20 20 20 52 54 53 0d 20 20 35 39 30 20 2e 66 | RTS. 590 .f|
00001ed0 6f 75 6e 64 0d 20 20 36 30 30 20 20 20 20 20 20 |ound. 600 |
00001ee0 20 20 20 4c 44 41 20 65 6e 61 62 66 6c 61 67 0d | LDA enabflag.|
00001ef0 20 20 36 31 30 20 20 20 20 20 20 20 20 20 42 45 | 610 BE|
00001f00 51 20 65 6e 61 62 6c 65 64 20 20 20 5c 20 46 6c |Q enabled \ Fl|
00001f10 61 67 20 67 6f 69 6e 67 20 66 72 6f 6d 20 26 30 |ag going from &0|
00001f20 31 20 74 6f 20 26 46 46 0d 20 20 36 32 30 20 20 |1 to &FF. 620 |
00001f30 20 20 20 20 20 20 20 50 4c 41 0d 20 20 36 33 30 | PLA. 630|
00001f40 20 20 20 20 20 20 20 20 20 50 4c 41 0d 20 20 36 | PLA. 6|
00001f50 34 30 20 20 20 20 20 20 20 20 20 50 4c 41 0d 20 |40 PLA. |
00001f60 20 36 35 30 20 20 20 20 20 20 20 20 20 4c 44 41 | 650 LDA|
00001f70 20 23 30 0d 20 20 36 36 30 20 20 20 20 20 20 20 | #0. 660 |
00001f80 20 20 52 54 53 0d 20 20 36 37 30 20 2e 65 6e 61 | RTS. 670 .ena|
00001f90 62 6c 65 64 0d 20 20 36 38 30 20 20 20 20 20 20 |bled. 680 |
00001fa0 20 20 20 4c 44 41 20 23 26 39 37 0d 20 20 36 39 | LDA #&97. 69|
00001fb0 30 20 20 20 20 20 20 20 20 20 4c 44 58 20 23 26 |0 LDX #&|
00001fc0 34 45 0d 20 20 37 30 30 20 20 20 20 20 20 20 20 |4E. 700 |
00001fd0 20 4c 44 59 20 23 26 37 46 0d 20 20 37 31 30 20 | LDY #&7F. 710 |
00001fe0 20 20 20 20 20 20 20 20 4a 53 52 20 6f 73 62 79 | JSR osby|
00001ff0 74 65 20 20 20 20 5c 20 2a 46 58 31 35 31 2c 37 |te \ *FX151,7|
00002000 38 2c 31 32 37 0d 20 20 37 32 30 20 20 20 20 20 |8,127. 720 |
00002010 20 20 20 20 4a 4d 50 20 28 72 65 73 65 74 29 0d | JMP (reset).|
00002020 20 20 37 33 30 20 2e 6c 61 73 74 62 79 74 65 0d | 730 .lastbyte.|
00002030 20 20 37 34 30 20 5d 0d 20 20 37 35 30 20 4e 45 | 740 ]. 750 NE|
00002040 58 54 0d 20 20 37 36 30 20 49 4e 50 55 54 27 22 |XT. 760 INPUT'"|
00002050 53 61 76 65 20 66 69 6c 65 6e 61 6d 65 20 3d 20 |Save filename = |
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00002070 20 49 46 20 66 69 6c 65 6e 61 6d 65 24 3d 22 22 | IF filename$=""|
00002080 20 45 4e 44 0d 20 20 37 38 30 20 24 73 61 76 65 | END. 780 $save|
00002090 3d 22 53 41 56 45 20 22 2b 66 69 6c 65 6e 61 6d |="SAVE "+filenam|
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000020b0 45 4d 29 2b 22 20 22 2b 53 54 52 24 7e 28 6c 61 |EM)+" "+STR$~(la|
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000020e0 30 30 22 0d 20 20 37 39 30 20 58 25 3d 73 61 76 |00". 790 X%=sav|
000020f0 65 20 4d 4f 44 20 32 35 36 0d 20 20 38 30 30 20 |e MOD 256. 800 |
00002100 59 25 3d 73 61 76 65 20 44 49 56 20 32 35 36 0d |Y%=save DIV 256.|
00002110 20 20 38 31 30 20 2a 4f 50 54 31 2c 32 0d 20 20 | 810 *OPT1,2. |
00002120 38 32 30 20 43 41 4c 4c 20 6f 73 63 6c 69 0d 20 |820 CALL oscli. |
00002130 20 38 33 30 20 2a 4f 50 54 31 2c 30 0d 20 20 38 | 830 *OPT1,0. 8|
00002140 34 30 20 45 4e 44 0d 20 20 38 35 30 20 44 45 46 |40 END. 850 DEF|
00002150 46 4e 65 71 75 62 28 62 79 74 65 29 0d 20 20 38 |FNequb(byte). 8|
00002160 36 30 20 3f 50 25 3d 62 79 74 65 0d 20 20 38 37 |60 ?P%=byte. 87|
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00002180 3d 70 61 73 73 0d 20 20 38 39 30 20 44 45 46 46 |=pass. 890 DEFF|
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000021c0 72 64 20 44 49 56 20 32 35 36 0d 20 20 39 32 30 |rd DIV 256. 920|
000021d0 20 50 25 3d 50 25 2b 32 0d 20 20 39 33 30 20 3d | P%=P%+2. 930 =|
000021e0 70 61 73 73 0d 20 20 39 34 30 20 44 45 46 46 4e |pass. 940 DEFFN|
000021f0 65 71 75 64 28 64 6f 75 62 6c 65 29 0d 20 20 39 |equd(double). 9|
00002200 35 30 20 21 50 25 3d 64 6f 75 62 6c 65 0d 20 20 |50 !P%=double. |
00002210 39 36 30 20 50 25 3d 50 25 2b 34 0d 20 20 39 37 |960 P%=P%+4. 97|
00002220 30 20 3d 70 61 73 73 0d 20 20 39 38 30 20 44 45 |0 =pass. 980 DE|
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00002240 0d 20 20 39 39 30 20 24 50 25 3d 73 74 72 69 6e |. 990 $P%=strin|
00002250 67 24 0d 20 31 30 30 30 20 50 25 3d 50 25 2b 4c |g$. 1000 P%=P%+L|
00002260 45 4e 28 73 74 72 69 6e 67 24 29 0d 20 31 30 31 |EN(string$). 101|
00002270 30 20 3d 70 61 73 73 0d |0 =pass.|
00002278 
13_11_87/T\SWR04.m0
13_11_87/T\SWR04.m1
13_11_87/T\SWR04.m2
13_11_87/T\SWR04.m4
13_11_87/T\SWR04.m5
.