Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > alt.os.development > #9309
| From | Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> |
|---|---|
| Newsgroups | alt.os.development |
| Subject | Re: Processor ISAs |
| Date | 2016-03-24 19:17 -0400 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <20160324191744.6b6a1d5a@_> (permalink) |
| References | <nd19lt$3h5$1@dont-email.me> |
On Thu, 24 Mar 2016 13:58:19 -0500 "Bill Cunningham" <billcun-remove-@suddenlink.net> wrote: > Would anyone happen to know which would have the simplest ISA? > I don't right off. Say old DEC stuff. Processors and Intel 8 bit > architectures? And of course the Z80. If various bit sizes of DEC > processors had simple instruction sets. Similar to RISC. Maybe they > would be more powerful land less to learn. Your post might also be a post for comp.arch or alt.folklore.computers. comp.arch will discuss the architecture design, and a.f.c. will discuss anything related to old computers, most likely the instruction sets in this case and stories from the past. The 68000 was used for teaching programming in schools throughout the 1990's. It's 32-bit. IIRC, it doesn't have an MMU like the later 68040 or a modern 80x86, and IIRC the instruction set is orthogonal. It was used in the second generation home PC's, such as Amiga 1000, Atari STs, and earlier Macintoshes. You can look it and all other microprocessors up on Wikipedia or Google. I "cut my teeth" on the 6510 (6502 variant) in the Commodore C64 in the 1980's. I picked up the general purpose 80x86 instructions of the 80486 and later rather easily in the early 2000's, but they were originally designed in the 1970's too. So, there was not much difference in terms of basic operations. I also learned some Z80 in magazines, also way back in the 1980's. Today, I don't recall the Z80 instructions other than it seemed simple, like the 6502. The Z80 was great for projects because it didn't need additional circuitry to drive the DRAM chips of the era. So, it was widely written about and used for hobby projects, much like the Parallax Stamp a decade ago, or the Raspberry Pi or Arduino today. The basic 6502 instructions are easy, but the 6502 is somewhat of a load-store architecture and only has a few registers. It has many memory addressing modes for each instruction to compensate for the lack of registers, i.e., mostly memory use. You'll need a copy of the manual for the chart with the memory modes to keep them straight. It has only one accumulator, meaning you're restricted to do most math through that register. It uses zero page (low 256 bytes) as a temporary register file or small stack. I.e., it's constrained, but simple. The basic general purpose instructions of the 8086 through 80486 and later are similar in functionality to the 6502, but you have eight general purpose registers, all of which can do general integer arithmetic. So, it's more orthogonal. Still, there are some instructions which only work with specific registers, being CISC. The 16-bit instruction set has a bunch of limited memory addressing modes, and other limitations, like early 8-bit processors. The 32-bit instruction set is much more orthogonal and uniform, but it not as clean as a RISC design. I never programmed the DEC's in assembly, but only used C. I only used a Timex Sinclair 1000 once at a friend's house. Rod Pemberton
Back to alt.os.development | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Processor ISAs "Bill Cunningham" <billcun-remove-@suddenlink.net> - 2016-03-24 13:58 -0500
Re: Processor ISAs "Alexei A. Frounze" <alexfrunews@gmail.com> - 2016-03-24 13:50 -0700
Re: Processor ISAs "Bill Cunningham" <billcun-remove-@suddenlink.net> - 2016-03-24 17:31 -0500
Re: Processor ISAs Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-24 19:17 -0400
Re: Processor ISAs "Benjamin David Lunt" <zfysz@fysnet.net> - 2016-03-24 17:50 -0700
Re: Processor ISAs "Bill Cunningham" <billcun-remove-@suddenlink.net> - 2016-03-25 13:21 -0500
Re: Processor ISAs "wolfgang kern" <nowhere@never.at> - 2016-03-25 08:24 +0100
Re: Processor ISAs Herbert Kleebauer <klee@unibwm.de> - 2016-03-25 12:43 +0100
Re: Processor ISAs Lucretia <laguest9000@googlemail.com> - 2016-03-28 06:45 -0700
Re: Processor ISAs Lucretia <laguest9000@googlemail.com> - 2016-03-28 06:54 -0700
Re: Processor ISAs "wolfgang kern" <nowhere@never.at> - 2016-03-28 22:40 +0200
Re: Processor ISAs Lucretia <laguest9000@googlemail.com> - 2016-03-29 13:00 -0700
Re: Processor ISAs "wolfgang kern" <nowhere@never.at> - 2016-03-30 11:17 +0200
Re: Processor ISAs James Harris <james.harris.1@gmail.com> - 2016-04-01 10:15 +0100
Re: Processor ISAs "wolfgang kern" <nowhere@never.at> - 2016-04-01 13:16 +0200
Re: Processor ISAs James Harris <james.harris.1@gmail.com> - 2016-04-01 22:48 +0100
OT: processor binary- or pin-compatibility, was [Re: Processor ISAs] Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-04-01 21:22 -0400
Re: OT: processor binary- or pin-compatibility, was [Re: Processor ISAs] Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-04-01 21:26 -0400
Re: OT: processor binary- or pin-compatibility, was [Re: Processor ISAs] Bob Eager <news0006@eager.cx> - 2016-04-02 08:46 +0000
Re: OT: processor binary- or pin-compatibility, was [Re: Processor Bogus@Embarq.com (Steve) - 2016-04-03 12:31 +0000
Re: OT: processor binary- or pin-compatibility, was [Re: Processor Morten Reistad <first@last.name.invalid> - 2016-04-03 14:44 +0200
Re: OT: processor binary- or pin-compatibility, was [Re: Processor Bob Eager <news0006@eager.cx> - 2016-04-03 18:53 +0000
Re: OT: processor binary- or pin-compatibility, was [Re: Processor Bogus@Embarq.com (Steve) - 2016-04-03 20:07 +0000
Re: OT: processor binary- or pin-compatibility, was [Re: Processor Bob Eager <news0006@eager.cx> - 2016-04-03 21:18 +0000
Re: OT: processor binary- or pin-compatibility, was [Re: Processor "J. Clarke" <j.clarke.873638@gmail.com> - 2016-04-03 20:20 -0400
Re: OT: processor binary- or pin-compatibility, was [Re: Processor "J. Clarke" <j.clarke.873638@gmail.com> - 2016-04-03 20:17 -0400
Re: OT: processor binary- or pin-compatibility, was [Re: Processor pechter@pechter.dyndns.org (William Pechter) - 2016-04-04 15:53 +0000
Re: processor binary- or pin-compatibility, was [Re: Processor ISAs] "Charles Richmond" <numerist@aquaporin4.com> - 2016-04-04 17:24 -0500
Re: processor binary- or pin-compatibility, was [Re: Processor ISAs] Bob Eager <news0006@eager.cx> - 2016-04-04 23:08 +0000
Re: processor binary- or pin-compatibility, was [Re: Processor ISAs] Bogus@Embarq.com (Steve) - 2016-04-05 17:43 +0000
Re: processor binary- or pin-compatibility, was [Re: Processor ISAs] Ahem A Rivet's Shot <steveo@eircom.net> - 2016-04-05 19:15 +0100
Re: Processor ISAs "wolfgang kern" <nowhere@never.at> - 2016-04-02 10:59 +0200
csiph-web