[A83] Re: What the heck is RST???
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[A83] Re: What the heck is RST???
If you want to load a ROM page into 8000h-BFFFh, then you just output the
page number to port 7.
--
Michael Vincent
Detached Solutions - www.detacheds.com
--
Senior Vice-President/Chief Software Architect
Radical Software - www.radicalsoft.org
----- Original Message -----
From: "Kirk Meyer" <kirk.meyer@colorado.edu>
To: <assembly-83@lists.ticalc.org>
Sent: Saturday, July 07, 2001 11:35 AM
Subject: [A83] Re: What the heck is RST???
>
> WARNING: This email is with the understanding that the inquirer is talking
> about TI-83+. If that was not the intent of the inquirer then no one
should
> read this email lest they become mad.
>
> TI does this in LoadCIndPaged and it can be called directly:
> push af
> in a,[6]
> push af
> ld a,b
> out [6],a
> ld c,[hl]
> pop af
> out [6],a
> pop af
> ret
>
> But obviously they're trying to preserve A here, so this is a bit
different
> thing than you're doing. Yours looks good if you need to include your own.
>
> Personally I prefer the use of TI's SetupPagedPtr followed by PagedGet (if
> you need to read lots of consecutive memory, anyway). These routines use a
> cache, and are described on p45-46 of the SDK guide. I bet that there is
> also a nice mm_ldir type function for copying big chunks of memory at once
> like on 86, but unfortunately, like so many of the available bcall's on
the
> 83+, it is not listed in ti83plus.inc, and I don't feel like hacking it
just
> now...
>
> Theoretically there is also a way to load a ROM page into the $8000-$BFFF
> area and use direct access. It seems to involve ports 4 and 6 together. I
> haven't been able to do much testing with this though.
>
> -----Original Message-----
> From: assembly-83-bounce@lists.ticalc.org
> [mailto:assembly-83-bounce@lists.ticalc.org]On Behalf Of Hyperbyte
> Sent: Saturday, July 07, 2001 12:19 PM
> To: assembly-83@lists.ticalc.org
> Subject: [A83] Re: What the heck is RST???
>
>
>
> Ehm, I suppose I need to make my own _ldaindpaged routine, can someone
give
> me a bit of advice?
>
> My idea so far:
> 1 - Since it needs to be in ram, copy it to a memory location
> if it is neccesary (when writing an app).
> 2 - the routine needs to reload the appage from where it is called,
> so it needs to store that. "in a,(06h)"??
> 3 - it needs to load the rompage specified and the hl specified, no
problem
> 5 - return to the right place and page for an app.
>
> Code so far:
> a: value of byte (output)
> b: rompage to load (input)
> hl: address to read from (input)
>
> Thrashes:
> c ; for speed issue
>
> Code:
>
> ld c,06h 2Eh 06h
> ld a,b 78h
> in b,(c) 40h EDh
> out (c),a 79h EDh
> ld a,(hl) 7Eh
> out (c),b 41h EDh
> ret C9h
>
> total: 11 bytes, fits in... saferam4 (ops), 8478h (according to ion.inc)
>
> Anyone a better idea? faster? smaller?
>
> --Peter-Martijn Kuipers
>
>
>
> > Yes -- or if you really want to use one of the calls which is on page 0
> (ex:
> > access to other ROM pages on 83+), get the call's pointer data, store it
> in
> > memory somewhere following a jp opcode, and call to that location
instead.
> >
> > -----Original Message-----
> > From: assembly-83-bounce@lists.ticalc.org
> > [mailto:assembly-83-bounce@lists.ticalc.org]On Behalf Of Dan Weiss
> > Sent: Saturday, July 07, 2001 11:17 AM
> > To: assembly-83@lists.ticalc.org
> > Subject: [A83] Re: What the heck is RST???
> >
> >
> >
> > Disassembly of BCALL: (hope TI doesn't sue me)
> >
> > 0028:
> > jp 284c
> > 284C:
> > push hl
> > push hl
> > push hl
> > push af
> > push bc
> > push de
> > push hl
> > ld hl,$000F
> > add hl,sp
> > ld d,(hl)
> > dec hl
> > ld e,(hl)
> > inc de
> > inc de
> > ld (hl),e
> > inc hl
> > ld (hl),d
> > in a,($06)
> > ld c,a
> > dec hl
> > dec hl
> > dec hl
> > ld (hl),a
> > dec hl
> > ld (hl),$29
> > dec hl
> > ld (hl),$23
> > dec de
> > ld a,(de)
> > ld h,a
> > dec de
> > ld a,(de)
> > ld l,a
> > ld b,$00
> > bit 7,h
> > jr nz,$2882
> > bit 6,h
> > jr z,$2888
> > res 6,h
> > ld a,$1B
> > jr $2893
> > 2882:
> > res 7,h
> > ld a,$1F
> > jr $2893
> > 2888:
> > in a,($06)
> > and $1F
> > ld de,$8230
> > add a,e
> > ld e,a
> > ld a,(de)
> > ld b,a
> > 2893:
> > out ($06),a
> > ld de,_ldhlind
> > add hl,de
> > ld e,l
> > ld d,h
> > ld hl,$0008
> > add hl,sp
> > inc de
> > inc hl
> > ld a,(de)
> > ld (hl),a
> > inc de
> > ld a,b
> > or a
> > jr z,$28B0
> > ld a,(de)
> > neg
> > ld a,b
> > jr $28B5
> > 28B0:
> > ld a,(de)
> > or a
> > jr nz,$28B5
> > ld a,c
> > 28B5:
> > out ($06),a
> > pop hl
> > pop de
> > pop bc
> > pop af
> > ret
> > ;113 bytes, 646 cycles
> >
> > This code plainly tells why to avoid romcalls whenever necessary... make
> > your own routines instead! (ESPECIALLY LD_HL_MHL!)
> >
> >
> >
> >
> > >From: Hyperbyte <hyper@hysoft-automation.com>
> > >Reply-To: assembly-83@lists.ticalc.org
> > >To: assembly-83@lists.ticalc.org
> > >Subject: [A83] Re: What the heck is RST???
> > >Date: Sat, 7 Jul 2001 18:47:06 +0200 (CEST)
> > >
> > >
> > >To give some more information, the code at 0028h (though I think it
> > >contains
> > >a jump to another rom area)
> > >reads the address to call from the stack, much like this code:
> > >
> > >pop ix ;get the address to retrieve info from
> > >ld h,(ix+0) ;retrieve the adrress to call to
> > >ld l,(ix+1) ;
> > >inc ix ; increase the address this routine should return to by 2,
> > >inc ix ; to account for the address data
> > >push ix ; push it back
> > >
> > >out pointerpage,(memswap_port) ;load the correct pointerpage
> > >push hl ;to store hl
> > >call real_call ;
> > >ret
> > >real_call: ;to be able to return, with 'ret' after the code is
> executed
> > >jp (hl)
> > >
> > >
> > >I think though that the real code is very different, but this
> > >gives a general idea, the real code also remembers the rompage you are
on
> > >when you call it
> > >
> > >--Peter-Martijn
> > >
> > >
> > >
> > > >
> > > >
> > > > >From: "Nick Reichert" <discjammer@hotmail.com>
> > > > >
> > > > >Hello,
> > > > >Can anyone tell me what "rst" does? It is part
> > > > >of the definition for B_CALL(#define B_CALL(xxxx)
> > > > >rst 28 // .dw xxxx or something like that), and
> > > > >it may give a little boost in speed. All I know
> > > > >is that it stands for restart, and "rst xxxx" is
> > > > >similar to "call xxxx", but what is the difference
> > > > >or advantage?
> > > >
> > > > "rst xx" is, as you said, the same as a call, but it's only one byte
> in
> > >size
> > > > and (most importantly) it only works on some predefined addresses:
> > >0000h,
> > > > 0008h, 0010h, 0018h, 0020h, 0028h, 0030h, 0038h.
> > > > The bcall macro is actually just a call to 0028h. The code at 28h
then
> > >looks
> > > > up the address defined after the rst and then calls the appropriate
> rom
> > > > routines.
> > > >
> > > > Tijl Coosemans
> > > >
> >
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> >
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> >
> >
>
>
>
>
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