Re: A86: Questions on Port 3, calc on, off, APD, etc
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Re: A86: Questions on Port 3, calc on, off, APD, etc
if you jumped to 66h it would skip the ex af,af' \ exx...
Matt2000 wrote:
> What ROM have you been smoking? At 66 is simply skips the user int routine,
> leading someone like me to believe that hey,
> NMI's are a possibility. One would assume an ON key interrupt would be an
> NMI. But when you do this it wouldnt crash, right?
>
> di
> halt
>
> Well it does. An NMI would be executed no matter what, skipping the di
> ignoring the halt and interrupting at any time. NMI just
> complicates hardware.. just disassembling the rom you can tell that TI
> wanted to save time and keep things pretty simple. They also seem to want
> the calc really stable too, with all those checksums.
>
> >Well, this is a little late (haven't been paying much attention to the list
> in
> >the past 2 weeks - still have 241 messages left to read)... Anyway, if
> anyone
> >still doesn't believe that there is no NMI, just disassemble at 66h, where
> the
> >Z80 NMI jumps to. You'll find that it is nothing.
> >
> >0038 08 ex af,af'
> >0039 d9 exx
> >003a fdcb2356 bit 2,(iy+$23)
> >003e 2826 jr z,$0066 ; (38)
> >0040 3afdd2 ld a,($d2fd)
> >0043 21fed2 ld hl,$d2fe
> >0046 96 sub (hl)
> >0047 2125d3 ld hl,$d325
> >004a 96 sub (hl)
> >004b 214dd3 ld hl,$d34d
> >004e 96 sub (hl)
> >004f 2175d3 ld hl,$d375
> >0052 96 sub (hl)
> >0053 219dd3 ld hl,$d39d
> >0056 96 sub (hl)
> >0057 21c5d3 ld hl,$d3c5
> >005a 96 sub (hl)
> >005b 2005 jr nz,$0062 ; (5)
> >005d cdfed2 call $d2fe
> >0060 1804 jr $0066 ; (4)
> >0062 fdcb2396 res 2,(iy+$23)
> >0066 db03 in a,($03)
> >0068 1f rra
> >0069 3824 jr c,$008f ; (36)
> >006b 1f rra
> >006c 3828 jr c,$0096 ; (40)
> >006e 1816 jr $0086 ; (22)
> >0070 fdcb1e76 bit 6,(iy+$1e)
> >0074 280e jr z,$0084 ; (14)
> >0076 47 ld b,a
> >0077 db01 in a,($01)
> >0079 4f ld c,a
> >007a 3eff ld a,$ff
> >007c d301 out ($01),a
> >007e cb41 bit 0,c
> >0080 ca5c0c jp z,$0c5c
> >0083 78 ld a,b
> >0084 d303 out ($03),a
> >0086 3e0b ld a,$0b
> >0088 d303 out ($03),a
> >008a 08 ex af,af'
> >008b d9 exx
> >008c fb ei
> >008d ed4d reti
> >
> >It's right in the middle of the intterupt routine!
> >
> >Matt2000 wrote:
> >
> >> >> I disassembled the ROM, the interrupt handler is fixed in the code, it
> >> makes
> >> >> a jump to the ON key interrupt handler routine. I did over 5 hours of
> >> >> disassebling and came to the conclusion there are no NMI's.. I have
> been
> >> >> reading some of the messages about interrupts by Jimmy Mardell and he
> >> also
> >> >> says "The TI-8x doesn't have any NMI's" and someone (maybe him) also
> says
> >> >> they haven't even seen a computer with an NMI
> >>
> >> di
> >> halt
> >> ret
> >>
> >> crashes the calc even if the ON key is pressed. It wont HARD lock the
> calc
> >> (meaning you have to take the lithium battery out)
> >> unless you put this code in the interrupt handler. Let me tell you a few
> >> things ----
> >>
> >> - The TI-86 has no NMI's
> >> - The ON key interrupt and the timer interrupt are both maskable
> interrupts
> >> and are both the same kind of interrupt
> >>
> >> There are some weird things that go on, something leads me to believe
> that
> >> something other then the ON key produces an
> >> ON key interrupt. I am doing experiements to find more information on
> this.
> >> I am soo close to completing a ROM 1.2 Down-Left bug patch
> >>
> >> Later,
> >> Matt
> >
> >
> >
> >--
> >Stephen Hicks
> >mailto:shicks@mindspring.com
> >ICQ:5453914
> >IRC/AIM:Kupopo
> >Hopemage:http://www.mindspring.com/~shicks/
> >
> >
--
Stephen Hicks
mailto:shicks@mindspring.com
ICQ:5453914
IRC/AIM:Kupopo
Hopemage:http://www.mindspring.com/~shicks/
References: