Does anybody know (or can point me in the right direction) of a byte sequence for a peripheral card that will autoboot from the monitor and allow for BASIC I/O entry points?[...]
And BASIC Init, In, Out are at cn00, cn05, and cn07 respectively.
Does anybody know (or can point me in the right direction) of a byte
sequence for a peripheral card that will autoboot from the monitor and
allow for BASIC I/O entry points? As far as I can tell, this area
overlaps, and you would end up running undocumented opcodes for the
BASIC I/O.
For reference, my understanding is that the Auto boot sequence is looking for:
cn01: 20
cn03: 00
cn05: 03
cn07: 3c
And BASIC Init, In, Out are at cn00, cn05, and cn07 respectively. I
think this means $03 (SLO) and $3C (NOP) would be run, which are
undocumented opcodes. Also, $20 would need to play some part in the
init sequence, either as a JSR, or address byte, or something. The
area is so tight that I can't figure out a solution even when running
the illegal ops. Thanks for any help.
On Tuesday, June 8, 2021 at 11:49:51 AM UTC-7, epoo...@gmail.com wrote:https://6502disassembly.com/a2-rom/AutoF8ROM.html#SymOUTPORT).
Does anybody know (or can point me in the right direction) of a byte sequence for a peripheral card that will autoboot from the monitor and allow for BASIC I/O entry points?[...]
And BASIC Init, In, Out are at cn00, cn05, and cn07 respectively.All BASIC does is redirect $36/37 or $38/39 to $Cn00. It's up to the card firmware to send it somewhere else. I'm looking at Applesoft's PR_NUMBER, which just calls the monitor OUTPORT (https://6502disassembly.com/a2-rom/Applesoft.html#SymPR_NUMBER and
Looking at an emulated Apple //e, the 80-column firmware at $C82A sets $36/37 to $c307, and $38/39 to $C305. You should be able to set these wherever you want, so long as you're not trying to pretend to be an 80-column card in slot 3... $C305/C307 aredocumented entry points.
What are you trying to do?
Does anybody know (or can point me in the right direction) of a byte
sequence for a peripheral card that will autoboot from the monitor and
allow for BASIC I/O entry points? As far as I can tell, this area
overlaps, and you would end up running undocumented opcodes for the
BASIC I/O.
For reference, my understanding is that the Auto boot sequence is looking for: >cn01: 20
cn03: 00
cn05: 03
cn07: 3c
And BASIC Init, In, Out are at cn00, cn05, and cn07 respectively. I
think this means $03 (SLO) and $3C (NOP) would be run, which are
undocumented opcodes. Also, $20 would need to play some part in the init >sequence, either as a JSR, or address byte, or something. The area is so >tight that I can't figure out a solution even when running the illegal
ops. Thanks for any help.
In article <ba9967f7-f576-4fac...@googlegroups.com>,
epoo...@gmail.com <epoo...@gmail.com> wrote:
Does anybody know (or can point me in the right direction) of a byte >sequence for a peripheral card that will autoboot from the monitor and >allow for BASIC I/O entry points? As far as I can tell, this area >overlaps, and you would end up running undocumented opcodes for the
BASIC I/O.
For reference, my understanding is that the Auto boot sequence is looking for:
cn01: 20
cn03: 00
cn05: 03
cn07: 3c
And BASIC Init, In, Out are at cn00, cn05, and cn07 respectively. II think it is intended to not be possible to have a card which can boot,
think this means $03 (SLO) and $3C (NOP) would be run, which are >undocumented opcodes. Also, $20 would need to play some part in the init >sequence, either as a JSR, or address byte, or something. The area is so >tight that I can't figure out a solution even when running the illegal >ops. Thanks for any help.
and which supports the standard character I/O interface.
Why do you want to do character in/out, and be bootable? It's likely if you only wanted to support PR#n and IN#n and not much else to use non-standard entry points: just update $36/37 or $38/39 to your entry points, and DOS/ ProDOS/Applesoft will work fine. But other programs expecting the Pascal entry points will not work.
Kent
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