[ot?] request for comment

From: Ron Hudson <rhudson_at_cnonline.net>
Date: Tue Aug 14 01:50:21 2001

Hi Chuck,

I would LOVE a scan of the booklet, also a scan of the
cpu side would help.

Is SIMPLEX on the web? or is it somthing you were working on
yourself?

====================



Chuck McManis wrote:

> I have a CARDIAC, perhaps I could scan the booklet for you. Or would you
> like to build something unique? I have a similar project called SIMPLEX
> which is a PDP/CARDIAC/uP inspired instructional computer architecture.
>
> --Chuck
>
> At 03:27 PM 8/12/01 -0700, you wrote:
>
>> I was going to write a simulator for Bell Labs "Cardiac" (cardboard
>> slide the slides and move bits be the cpu your self) computer, but all
>> I can find is the Instruction Set, none of how the instructions are
>> implemented.
>>
>> So, I decieded to write my own...
>> Here is the instruction set, I thought it best to consult with you
>> all before beginning to code. What
>> do you think?
>> Opcodes
>>
>> 0 1 2 3 4 5 6 7
>> Z N o1 o2 o3
>> =================================================================
>> Z N 0 0 1 i r r get copy (indirect) register rr to acx
>>
>> Z N 0 1 0 i r r put copy (indirect) acx to register rr
>>
>> Z N 0 1 1 o o o Mathop
>>
>> 0 0 0 nop
>> 0 0 1 add acx + acy ==> acx
>> 0 1 0 sub acx - acy ==> acx
>> 0 1 1 and acx & acy ==> acx
>> 1 0 0 exor acx xor acy ==> acx
>> 1 0 1 or acx | acy ==> acx
>> 1 1 0 cmp acx cmp acy set Z and N
>> 1 1 1 cpz acx cmp 0 set Z and N
>>
>> Z N 1 0 0 p p p inp copy port ppp ==> acx
>>
>> Z N 1 0 1 p p p out copy acx ==> port ppp
>>
>> Z N 1 1 0 i r r swp acx ==> (ind) Rn == > acx
>>
>> Z N 1 1 1 0 o o acx op group
>>
>> 0 0 0 not r1 <== ! r1
>> 0 0 1 shl Shift left
>> 0 1 0 shr Shift right
>> 0 1 1 inc Increment r1 <== r1 + 1
>>
>> Z N 1 1 1 1 o o Jump Group
>>
>> 1 0 0 jmp ind [pc] pc <== [pc]
>> 1 0 1 jsr ind [pc] R2 <== pc , pc <==
>> [pc]
>> 1 1 0 rtn pc <== R2
>> 1 1 1 Halt,reset [pc] <== 0
>>
>> Zero and Negative flags
>>
>> On execution of the cmp and cpz instructions the Z and N flags are
>> set, following instructions can test these flags and choose to execute
>> or not.
>>
>> Z N Meaning
>> 0 0 Execute if acx was positive on test (acx > 0 / acx > acy)
>> 0 1 Execute if acx was negative on test (acx < 0 / acx < acy)
>> 1 0 Execute if acx was zeron on test (acx = 0 / acx = acy)
>> 1 1 Always execute
>>
>>
>> Registers
>> 00 r0 acx 1st operand
>> 01 r1 acy 2nd operand
>> 10 r2 ptr Pointer register
>> 11 r3 pc Program Counter
>>
>>
>> here is an example of an assembled program....
>>
>> Assembly of a simple program
>>
>> org $10 ; program starts at 10 10
>>
>> get ind pc ; load value1 acy 10 11001111 00010000
>> adr value1 11 00011001 00010001
>> swp acy 12 11110110 00010010
>>
>> get ind pc ; load value2 acx 13 11001111 00010011
>> adr value2 14 00011010 00010100
>>
>> add ; sum values 15 11011001 00010101
>>
>> put ind pc ; store sum 16 11010111 00010110
>> adr sum 17 00011011 00010111
>>
>> hlt ; end of program 18 11111111 00011000
>>
>> value1 byt 19 00011001
>> value2 byt 1A 00011010
>> sum byt 1B 00011011
>>
>>
>> end ; end of code
>>
>>
>>
>> I know, it only has 256 words of 8 bit memory, but isn't this as much
>> as some of the early machines?
>>
Received on Tue Aug 14 2001 - 01:50:21 BST