i'd try those routines with a very simple text terminal implementation first, and see if the flow control works right. XON/OFF is always a bit tricky, so it might just be the thresholds that need tweaking. Am Sonntag, 1. Juli 2018, 19:32:04 CEST schrieb Thom Cherryhomes: > great, now if only I can figure out wtf to do... I'm not a skilled C64 > programmer, am only passing through to write this terminal. > > -Thom > > On Sun, Jul 1, 2018 at 12:30 PM David Roberts <daver21145@gmail.com> wrote: > > I have never used cc65 - but I know programmers who have been caught out > > on other platforms. > > > > NMI routines need to make sure that all CPU registers are saved/restored > > and that data structures remain intact. If the NMI routine changes > > anything > > that is relied on outside of it (without the appropriate protection) you > > are in trouble... > > > > Interrupts can be inhibited during critical processing outside of the > > interrupt service routine. An NMI requires special treatment. We use NMI > > as > > a critical error and real-time clock handler (in preference to an > > interrupt) in a piece of communications hardware we use; but the hardware > > contains a mechanism for (very briefly) disabling the NMI around very > > critical data structures that absolutely must not be modified should a > > critical error (such as a bus timeout on the MULTIBUS) occur. > > > > Not sure how much of this is relevant to your problem, but it fits the > > symptoms you have... > > > > Dave > > > > On Sunday, 1 July 2018, Thom Cherryhomes <thom.cherryhomes@gmail.com> > > > > wrote: > >> The up2400 routines use the NMI to do all the shifting and filling of the > >> buffers. > >> > >> I'm not entirely sure volatile has any meaningful consequence in cc65. > >> > >> -Thom > >> > >> On Sun, Jul 1, 2018 at 11:54 AM David Roberts <daver21145@gmail.com> > >> > >> wrote: > >>> I have only just had a cursory look at the sources, but does anything > >>> use interrupts? Usually interrupts cause unexpected results. > >>> > >>> The other thing to be wary of (with C code) is the ability of the > >>> hardware to change stuff 'under' the compiler's feet... If C code is > >>> mapped > >>> onto hardware anywhere - you need to use the 'volatile' keyword to force > >>> the compiler to re-read the data before use as opposed to using its own > >>> cached value. > >>> > >>> Just a couple of thoughts... > >>> > >>> Dave > >>> > >>> > >>> On Sunday, 1 July 2018, Thom Cherryhomes <thom.cherryhomes@gmail.com> > >>> > >>> wrote: > >>>> Hello, everyone. > >>>> > >>>> My name is Thom Cherryhomes, and I am both the systems operator of > >>>> IRATA.ONLINE, and developing a series of terminal programs for > >>>> different > >>>> machines that can connect to the currently running PLATO systems en > >>>> extant: > >>>> IRATA.ONLINE, and CYBER1.ORG. > >>>> > >>>> I've gotten the vast majority of the terminal written, using CC65, and > >>>> appropriating some bits of code from other places, namely: > >>>> > >>>> * up2400 for cc65 based on George Hug's user-port 2400 driver. > >>>> https://github.com/nanoflite/c64-up2400-cc65 > >>>> > >>>> * The swiftlink driver for cc65: > >>>> https://github.com/gilligan/snesdev/blob/master/tools/cc65-2.13.2/libsr > >>>> c/c64/c64-swlink.s > >>>> > >>>> * ip65 for ethernet support https://github.com/oliverschmidt/ip65 > >>>> > >>>> As I said, the terminal is mostly functioning, but I am having problems > >>>> when flow control needs to assert itself, The type of flow control that > >>>> PLATO supports is XON/XOFF, so I've implemented a threshold model that > >>>> sends XON/XOFF based on threshold values: > >>>> https://github.com/tschak909/platoterm64/blob/master/src/io.c#L20 > >>>> > >>>> #define XOFF_THRESHOLD 250 > >>>> #define XON_THRESHOLD 100 > >>>> And this is asserted during the io_recv_serial() which gets called > >>>> every pass through the main loop: > >>>> https://github.com/tschak909/platoterm64/blob/master/src/io.c#L20 > >>>> > >>>> I understand that the code as is only works with user-port devices > >>>> (because up2400 re-uses the kernal structures), these are the devices > >>>> that > >>>> need it most, and I am trying to get these devices working, before I > >>>> refine > >>>> things for the swiftlink cartridge. > >>>> > >>>> However, what happens, is something like this: > >>>> https://www.youtube.com/watch?v=K9VgIigaJzw > >>>> > >>>> and this: > >>>> https://www.youtube.com/watch?v=xjSlCOPXYRk > >>>> > >>>> I'm not entirely sure what's happening here, as the buffer is filling > >>>> up, and draining, and the amount of glitching is directly proportional > >>>> to > >>>> the tiniest bits of changes in my drawing routines. The one biggest > >>>> cause > >>>> of glitch is the block erase routine (which given a set of pixel > >>>> coordinates, erases an area of the screen...the cc65 implementation > >>>> draws > >>>> horizontal lines until the bottom of the bounding box is reached... I > >>>> would > >>>> think this would simply cause the buffer to fill up, which would cause > >>>> xoff > >>>> to trip, stuff would stop being sent, and the buffer would subsequently > >>>> be > >>>> drained until the buffer is empty...but something very subtly wrong is > >>>> happening. > >>>> > >>>> I have already spent days messing with the threshold values, as well as > >>>> trying to shuffle code around to try and alleviate the problem, but I > >>>> seem > >>>> to just keep getting the short end of the stick on this one. > >>>> > >>>> Could really use some help, any insights? > >>>> > >>>> Code is here btw: http://github.com/tschak909/platoterm64 > >>>> > >>>> -Thom -- http://hitmen.eu http://ar.pokefinder.org http://vice-emu.sourceforge.net http://magicdisk.untergrund.net Habe ich schon erwähnt, daß mir HDTV/Blueray/HD-DVD völlig am Allerwertesten vorbeigehen? Das derzeitige Programm noch hochauflösender zu sehen, empfinde ich als Drohung.Received on 2018-07-01 20:02:13
Archive generated by hypermail 2.2.0.