Posted By
Litwr
on 2013-08-26
13:25:53
|  Yet another emulator error
I've just found that Yape and Plus4emu at the debugger step-by-step execution miss to call interrupts. It is easier to check with Plus4emu because it allows breakpoints for the line number and horizontal position pair. I set breakpoint to 00cb:b4 (line 203) then in the debugger window I make several steps and can't meet interrupt. 
BTW old '+4forever?' works with such interrupts. However it is not so accurate as Yape or Plus4emu. Can we get a perfect emulator one day?
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Posted By
MIK
on 2013-08-26
14:15:57
 | Re: Yet another emulator error
Put Gaia on a BIG pay roll so he can give up his day job and that perfect Plus/4 emulator is yours. 
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Posted By
Litwr
on 2013-08-28
06:40:36
| Re: Yet another emulator error
I've just found other two bugs. Try
>ff06 18
at monitor. The Yape's bottom line differs from this line at Plus4emu, '+4forever?' or the real hardware. The second bug is tricky. Try to enter the next code
a 2000 STA $FF3F
. 2003 LDA #$40
. 2005 STA $FFFE
. 2008 LDA #$20
. 200A STA $FFFF
. 200D LDA #$14
. 200F STA $FF0B
. 2012 LDA #$A3
. 2014 STA $FF0A
. 2017 LDX #$37
. 2019 JMP $2019
a 2040 STX $FF1D
. 2043 LDA #$C2
. 2045 STA $FF0B
. 2048 LDA #$A2
. 204A STA $FF0A
. 204D LDA #$80
. 204F STA $FFFE
. 2052 LDA #$72
. 2054 INC $FF09
. 2057 RTI
a 2080 STA $FF1D
. 2083 LDA #$CD
. 2085 STA $FF0B
. 2088 LDA #$A0
. 208A STA $FFFE
. 208D LDA #$FA
. 208F INC $FF09
. 2092 RTI
a 20A0 STA $FF1D
. 20A3 LDA #$14
. 20A5 STA $FF0B
. 20A8 LDA #$A3
. 20AA STA $FF0A
. 20AD LDA #$40
. 20AF STA $FFFE
. 20B2 INC $FF09
. 20B5 RTI
g2000
Yape and '+4forever?' show 320x280 picture (40x35 text) but the real hardware or plus4emu show the wrong vertical synchronization. This code maybe taken from here.
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Posted By
Gaia
on 2013-08-28
16:22:49
| Re: Yet another emulator error
Thanks for the feedback! Breakpoints are not emulation related in the strict sense of the word. So it's rather a missing feature I'd say. Perhaps it's an easy fix, I'll have a look.
About sync signals: I think I mention it in the TODO file attached with YAPE that these are only partially implemented. Unfortunately this will likely remain so until at least 20 years from now, unless a time-warp occurs 
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Posted By
Csabo
on 2013-08-29
09:47:02
| Re: Yet another emulator error
Only 20 years? Whoo boy, 2033, perfect YAPE, here I come!
Seriously, what the issue there? Is it Plus/4 related (as in, has to do with the machine/chips) or TV/monitor related?
Could it be a problem with the code? I recall that a while back I wrote a short test which expanded the screen to "as much as possible", and even had someone test it on the real iron, and they said it was fine. Though my memory is a bit hazy on that part, I'd have to dig it up I guess.
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Posted By
bubis
on 2013-08-29
10:29:21
| Re: Yet another emulator error
@MIK: Good point.
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Posted By
Litwr
on 2013-08-30
03:20:23
| Re: Yet another emulator error
@Csabo: What type of hardware did you use? I tried it with old analogue TV via RCA connectors (no TV modulation) - it shows wrong sync. Plus4emu is very accurate thing - it also shows bad sync. This code can be easily transformed to fine but its purpose was only to show a bug.
***edit*** The PAL's maximum is 40x36 (320x288), not 40x35 - I may send the proof to you. IMHO NTSC's maximum is 40x29 but it is not checked. It is very odd that these additional text rows or bitmap lines were not used by software - 3+1 uses only 38x24 mode! :-( They may be very good for text editors, some kind of games, graphical editors/viewers, ... Even p4fliconv doesn't use all possible lines. :-(
@Gaia: It is not about breakpoints. It is about bug in the step-by-step execution feature. This bug is very little... It is also curious why YAPE shows another bottom line after >ff06 18?
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Posted By
Luca
on 2013-09-22
12:50:05
 | Re: Yet another emulator error
The loader of the forthcoming Linguaggio Macchina 16/20 (PDICT) tape uses a little pre-code that doesn't work on YAPE (it works in plus4emu).
EDIT: no wait a moment...
The video effect in plus4emu id for sure closer to real iron, but the loaders works better or not depending on the tool used to produce the final TAP file.
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Posted By
Gaia
on 2013-09-23
15:41:02
| Re: Yet another emulator error
ché?
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Posted By
Luca
on 2013-09-23
15:50:17
| Re: Yet another emulator error
Oh well you'll see that soon
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