Circuit Cellar Issue 100 Cantrell Table 1

Table 1—To ease programming and accomodate new features, Scenix adds 10 new instructions for a still RISCy grand total of 43.


                             
                               
                                Command 
                              
                               
                                Description 
                                  
                              
                            
                             
                               
                                PAGE n 
                              
                               
                                Switch 
                                  to new instruction page
                              
                            
                             
                               
                                BANK 
                                  n 
                              
                               
                                Switch 
                                  to new register bank
                              
                            
                             
                               
                                RET
                              
                               
                                Return 
                                  without affecting W 
                              
                            
                             
                               
                                RETP 
                                  
                              
                               
                                Return 
                                  across page boundary
                              
                            
                             
                               
                                RETI
                              
                               
                                Return 
                                  from interrupt and restore state
                              
                            
                             
                               
                                RETIW 
                                  
                              
                               
                                Return 
                                  from interrupt and reload timer
                              
                            
                             
                               
                                IREAD
                              
                               
                                Read 
                                  instruction memory
                              
                            
                             
                               
                                MOV 
                                  !M,W 
                              
                               
                                Write 
                                  I/O mode bits
                              
                            
                             
                               
                                MOV 
                                  W,!M 
                              
                               
                                Read 
                                  I/O mode bits
                              
                            
                             
                               
                                MOV 
                                  !rx,#imm 
                              
                               
                                Write 
                                  immediate to port control register

Command	Description
PAGE n	Switch to new instruction page
BANK n	Switch to new register bank
RET	Return without affecting W
RETP	Return across page boundary
RETI	Return from interrupt and restore state
RETIW	Return from interrupt and reload timer
IREAD	Read instruction memory
MOV !M,W	Write I/O mode bits
MOV W,!M	Read I/O mode bits
MOV !rx,#imm	Write immediate to port control register