Re: Proposed Assembler Commands

On Sun, 1 May 2005 19:44:41 +0000 (UTC), kensmith@xxxxxxxxxxxxxxx (Ken
Smith) wrote:

>In article <6sh871h65ksdq0trjpb19gurt7n0jmgdm8@xxxxxxx>,
>John Larkin <jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>[...]
>>I always liked the Moto instruction sets. The Intel stuff has always
>>seemed klugey and disorganized to me. So, we all wound up with the
>>worst instruction set and the worst OS the industry could invent.
>
>
>You've obviously never seen the RCA CDP1802's instruction set.
>
>Imagine you have 3, 1 byte variable in memory and wish to do C = A + B
>here's the code for it (If my memory is working today):
>
>
> LDI low(A) .. Load the low part of an address
> PLO R2 .. Put into the low part of the reg
> LDI high(A) .. Same for the high byte
> PHI R2
>
> LDI low(B) .. Load the low part of an address
> PLO R3 .. Put into the low part of the reg
> LDI high(B) .. Same for the high byte
> PHI R3
>
> LDI low(C) .. Load the low part of an address
> PLO R4 .. Put into the low part of the reg
> LDI high(C) .. Same for the high byte
> PHI R4
>
>
> LDN R2
> SEX R3
> ADD
> STD R4
>
>
>That right folks only 16 instructions needed for that.
>

Sounds tedious.

680x:

LDAA A
ADAA B
STAA C

PDP-11:

MOVB A, C
ADDB B, C

The PDP-11 had an elegant, symmetric, beautiful instruction set. I
haven't programmed one in decades, but I can still mentally assemble
most common instructions (into octal!)

John


.

Relevant Pages

  • Re: Proposed Assembler Commands
    ... >>>worst instruction set and the worst OS the industry could invent. ... I often suspect that you haven't a clue what you're talking about. ... Load the low part of an address ... >> PHI R2 ...
    (sci.electronics.design)
  • Re: Proposed Assembler Commands
    ... >>worst instruction set and the worst OS the industry could invent. ... > LDI low.. ... Load the low part of an address ... > PHI R2 ...
    (sci.electronics.design)
  • Re: Proposed Assembler Commands
    ... >seemed klugey and disorganized to me. ... we all wound up with the ... You've obviously never seen the RCA CDP1802's instruction set. ... PHI R2 ...
    (sci.electronics.design)
  • Re: what uC do you prefer?
    ... the 68332, it has a register-rich, symmetric, very PDP-11 looking ... Then take a look at my web page on the instruction set, ... elegant than an Intel or PIC architecture. ...
    (sci.electronics.basics)
  • Re: CFO: Why C?
    ... > processors typically have an architecture and instruction set which is ... > the compiler must add explicit instructions for these operators. ... provided by the DEC PDP-11 on which C and Unix first became popular. ...
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