-------------------------------------- INTERNET-ECKE -------------------------------------- In article , Lonnie McClure wrote: > >In a message dated 8-30-94, BRYEDEWAARD@DELPHI.COM said: > > "The 6502 only uses a byte for opcode. The individual bits > all mean something and the combinations of them make up > the logical instructions. This means the instructions are > not "interpreted" but rather trigger direct microcode sequences." > >Unless I am very seriously mistaken, microcode is not involved in the >6502 at all. Rather, like many of its early 8-bit brethren (such as >the 6809), its instructions are "hardwired", which also partially >explains their high cycle speed and relatively small instruction sets. I've read 6502 documentation that mentions that it uses a "hybrid design" which indicates to me that it uses a mix of both hardwiring and microcode. - Robin Empfaenger : /COMP/SYS/ATARI/8BIT Absender : Rick_Michael_Cortese@cup.portal.com Betreff : Re: 65816 /32 info Datum : Mi 07.09.94, 14:59 (erhalten: 09.09.94) Groesse : 3858 Bytes --------------------------------------- I pulled out my old 1802 stuff because of some of the statements about relative merits of different processors. Stuff is so old it looks like the Dead Sea Scrolls. Anyway, there may be a few errors in this because I'm doing it off the top of my head on a word processor. There's other ways of doing it, but: POINT #1 Size of code vs 6502 POINT #2 can page zero be considered registers Let's say you want to do a simple memory move, 6502 would be something like 4 pages $2000M TO $4000M: LDA $40 STA DEST+1 LDA $00 STA DEST LDA $20 STA START+1 LDA $00 STA START LDX #$4 LDY #$0 LOOP1 LDA (START),Y STA (DEST),Y DEY BEQ LOOP1 INC START+1 INC DEST+1 DEX BMI END BPL LOOP1 END BRK I get about 37 bytes with the BRK at the end. On an 1802 the same thing would go something like this . Note the equivalent of the 6502 A reg is called D on the 1802: $F8 $40 LOAD D REG WITH HIGH DEST $B1 PUT IT IN HIGH PART OF REG #1 $F8 $00 LOW IN D $A1 PUT IN LOW PART OF REG #1 $F8 $20 SOURCE LOAD AS ABOVE $B2 REG #2 $F8 $00 $A2 $42 LOAD D WITH DATA POINTED TO BY REG #2 $51 STORE CONTENTS OF D @ REG #2 POINTER $12 INC REG #2 THIS IS A 16 BIT INC $11 INC REG #1 DITTO $91 GET HI REG #1 $FB $07 COMPARE: HAS IT BEEN INC FROM 4 TO 8? $3A $0C BNZ $0C BACK $00 IDLE/HALT 22 bytes. Both could have been written smaller, but both used the same style of programing & it illustrates my point #1 on size of code very well. Most other examples I could think of such as branching, math, subroutines, etcetera are similar. I haven't really delved that much into Z80 & 80xx, but what I have seen shows a similar reduction in memory requirements. Aside from the power restrictions of running on a Plutonium based thermoelectric supply, the 1802 WAS the right choice for Voyager when you consider the size of cmos rams available when it was built. Point #2 the 6502 can use page zero memory locations to perform some register like functions, but so few that it doesn't make a lot of sense to say they are the same as real registers. For example, you can also do a JSR($5000), but you wouldn't consider saying there's 64k of registers in a 800xl. *IF* they could be used in a single op code like TAY or TXA then they would qualify, but if it looks like a duck, walks like a duck, quacks like a duck, it's memory. I've even heard about some Z80 designs that don't even use ram, just a ROM with the program & internal registers for all data storage & manipulation. Try that with a 6502 & you'll really see some of the limitations we have. The 6502 is my processor of choice, but I can see why some people prefer other processors. A limitation of the 1802 is you only have a maximum o 7 hardware devices, since a 6502 uses memory mapped devices, it's only limited by address space. You could do memory mapped stuff on a 1802, but then you lose some of the features that make the ability to have 7 hardware devices directly accessible by the processor desirable. Empfaenger : /COMP/SYS/ATARI/8BIT Absender : kendrick@zippy.sonoma.edu (William Kendrick) Betreff : Re: Scrolling Ad Software Wanted Datum : Mo 12.09.94, 03:55 (erhalten: 12.09.94) Groesse : 1158 Bytes --------------------------------------- Man, there's probably a LOT of that out there! Heheh.. if you wanted, you could even use a sector editor and hack into a demo (like the one's from Europe) and change the text in the scrollers and you'll have whatever nifty thing is in the background .. in the background.. that make sense. ?? ANYWAYS, or write something simple in TurboBASIC XL like: 10 GRAPHICS 15+16:SETCOLOR 0,0,15:POKE 559,35 15 DIM A$(100) 20 A$=" Welcome to my store...." 25 A$(LEN(A$)+1)=" " 30 DO 35 X=X-1 40 IF X<0 THEN X=7 45 IF X=7 THEN Y=Y+1:IF Y>LEN(A$)-48 THEN Y=1 50 TEXT X,32,A$(Y) 55 LOOP oops. ok, that won't work, but it's close.. if you can stand the letters vanishing instantly at the left edge and the screen having a border than just remove the "POKE 559,35" and change "-48" to "-40" and it'll look ok I guess.. a bit small I must be bored. :) Nevermind that, I know there's quite a bit of scroller software out there for the purpose you stated.. :) -bill kendrick@vax.sonoma.edu ööö kendrick@zippy.sonoma.edu William (Bill) Kendrick / ö Ö ** New Breed Software ** Empfaenger : /COMP/SYS/ATARI/8BIT Absender : jharris@cup.portal.com (John D Harris) Betreff : Re: 65816 /32 info Datum : Mo 12.09.94, 00:52 (erhalten: 12.09.94) Groesse : 956 Bytes --------------------------------------- > POINT #1 Size of code vs 6502 The 65816, which is the processor I called the most memory efficient, can do your memory move example in 12 bytes, vs 22 for 1802 and 30+ 6502. That's assuming the chip was in 16 bit register mode already, or else you would need 2 bytes to switch into 16 bit mode first, and 2 more bytes to switch to 8 bit mode after the move, if necessary. So 16 bytes max. > POINT #2 can page zero be considered registers Registers on other machines are often used for counters, and indirect memory pointers, of which ZP can do both. While I don't call a 6502 a machine with 256+3 registers, I don't usually have major problems doing what I need to accomplish within the confines of the chip. The main thing I run into, is needing to add something when I don't want to trash the A register. The 68000 having 8 data registers is really nice in that regard. John Harris - jharris@cup.portal.com Empfaenger : /COMP/SYS/ATARI/8BIT Absender : jharris@cup.portal.com (John D Harris) Betreff : Re: Ansi on AnsiTerm!!! Datum : Di 13.09.94, 23:09 (erhalten: 15.09.94) Groesse : 465 Bytes --------------------------------------- >The Atari hardware does not allow interrupt driven keyboard input... On the contrary, the Atari keyboard interface is IRQ interrupt driven. I've also done programs which turn off the IRQ's and read the keyboard port (only one hardware register) on vertical blank, and I use type ahead buffers with both methods. Missing keys would be a fault of the specific software program, because the hardware is very capable. John Harris - jharris@cup.portal.com Empfaenger : /COMP/SYS/ATARI/8BIT Absender : krishna@max.tiac.net (Glenn M. Saunders) Betreff : Re: Ansi on AnsiTerm!!! Datum : Di 13.09.94, 23:55 (erhalten: 15.09.94) Groesse : 602 Bytes --------------------------------------- richard.b.dell (rdell@cbnewsf.cb.att.com) wrote: : The Atari hardware does not allow interrupt driven keyboard input. : The keyboard is polled thru it's matrix looking for a key press by : software (as I recall). All comparasons to_any_ system with : interrupt driven keyboard routines will find the Atari method : lacking ... especially for those of us used to typing ahead. : There is no way for the Atari to know a key is pressed until it : goes to look for it, which makes it easy for the Atari to miss : keys. Yes and no. Sparta manages to get around this with "key on" ya know. Empfaenger : /COMP/SYS/ATARI/8BIT Absender : rdell@cbnewsf.cb.att.com (richard.b.dell) Weiterleiter news@cbfsb.cb.att.com Betreff : Re: Ansi on AnsiTerm!!! Datum : Mi 14.09.94, 12:21 (erhalten: 15.09.94) Groesse : 461 Bytes --------------------------------------- In article <122363@cup.portal.com> jharris@cup.portal.com (John D Harris) writes: >>The Atari hardware does not allow interrupt driven keyboard input... > >On the contrary, the Atari keyboard interface is IRQ interrupt driven. Just goes to show what relying on memory of schematics not looked at recently will do! Thanks for the correction, and I should have known Atari would build the function into their custom logic chips. -- Richard Dell Empfaenger : /COMP/SYS/ATARI/8BIT Absender : vparada@inf.utfsm.cl (Victor Parada G.) Betreff : Re: DCM format Datum : Mi 14.09.94, 09:22 (erhalten: 15.09.94) Groesse : 631 Bytes --------------------------------------- Please post any answer... I'm trying to extract files from a .DCM disk in unix, just to read/print the docs without transfering it to a PC and running the emulator, or transfer only the right binary to my 8 bit. Of course, I must check the format type of the unDCM disk image before process it. Thanks... ++Vitoco -- Lic. Victor Andres Parada Gomez __ __ Universidad Tecnica Ingenieria Civil en Informatica o-''))_____ÖÖ Federico Santa Maria, mailto:vparada@inf.utfsm.cl "--__/ * * * ) Valparaiso, CHILE. http://www.inf.utfsm.cl/ßvparada/ c_c__/-c____/ (+56)32-626364x431 :-) Empfaenger : /COMP/SYS/ATARI/8BIT Absender : rfunk@magnus.acs.ohio-state.edu (Rob Funk) Betreff : Re: DCM format Datum : Mi 14.09.94, 17:23 (erhalten: 15.09.94) Groesse : 896 Bytes --------------------------------------- In article <356tdr$22v@inti.inf.utfsm.cl>, Victor Parada G. wrote: >Please post any answer... I'm trying to extract files from a .DCM >disk in unix, just to read/print the docs without transfering it to >a PC and running the emulator, or transfer only the right binary >to my 8 bit. Of course, I must check the format type of the unDCM >disk image before process it. I know this isn't exactly what you want, but it _might_ help until someone gives more info: try the unix "strings" command. Of course, this won't work if DCM is a compressed format. Empfaenger : /COMP/SYS/ATARI/8BIT Absender : cmwagner@gate.net (Chad Wagner) Betreff : Re: DCM format Datum : Do 15.09.94, 06:42 (erhalten: 16.09.94) Groesse : 730 Bytes --------------------------------------- Victor Parada G. (vparada@inf.utfsm.cl) wrote: : Please post any answer... I'm trying to extract files from a .DCM : disk in unix, just to read/print the docs without transfering it to : a PC and running the emulator, or transfer only the right binary : to my 8 bit. Of course, I must check the format type of the unDCM : disk image before process it. Will do. I really don't want to waste time reverse engineering something when the information is already available, and there is already utilities for the IBM (and other platforms) that let you manipulate DCM format images. I heard that DCM is using RLE for compression, but what is the escape code and how is the header setup and what does it mean? Oh well. Empfaenger : /COMP/SYS/ATARI/8BIT Absender : tatar@student.uci.agh.edu.pl (Tomasz Tatar) Betreff : Re: Pictures of old 8-bit Ataris Datum : Mi 14.09.94, 15:47 (erhalten: 16.09.94) Groesse : 887 Bytes --------------------------------------- Michael Current (aa700@cleveland.Freenet.Edu) wrote: : You know what would really be cool? If you scanned everything you could, : then coordinated it with one or more of the 8-bit Atari WWW page moderators : so they could provide graphics in their offerings. I know at least one was : looking for such pictures. I think it is great idea! I'd like place some Atari photos on my Big Atari 8bit Home Page, but I didn't get any of them. Unfortunatelly, I haven't too many space on my disk, so I can't keep all 640x480x256 graphics. However, I'll place them after scaling down. Mail your pictures to The Gatekeeper, I suggest. I'll get all of them from your archive and choose some photos to use on my pages. RIPI, Gatekeeper, what do you think? Tomasz M. Tatar tatar@student.uci.agh.edu.pl http://www.uci.agh.edu.pl/student/robo1gghHHI