The previous log The SIMPL Machine, looked at how the J1 Forth CPU simulation could be used as the basis of a cpu targeted to execute the SIMPL language. 

Here are some notes regarding the implementation on the Teensy 4.0

A switch-case structure will translate the SIMPL ascii character commands into 16-bit instructions to feed the J1 cpu simulated cpu.

I took the SIMPL text interpreter framework and mapped into it the J1 instructions, focusing initially on the stack, ALU and memory operations – listed below

SIMPL               Operation                J1 hex code

”                   DUP                      6081

‘                   DROP                     6183

$                   SWAP                     6180

%                   OVER                     6181

+                   ADD                      6203

&                   AND                      6303

|                   OR                       6403

^                   XOR                      6503

~                   INV                      6600

@                   FETCH                    6C00

!                   STORE                    6123