Instruction Sets of 6812

68HC12 has more than1000 instructions. They are grouped into a few functional categories as following :

1)    Data Transfer and Manipulation Instructions —instructions which move and manipulate data :

                                                      i.        Load and Store — load copy of memory contents into a register; store copy of register contents into memory.

                                                     ii.        Transfer —copy contents of one register to another.

                                                    iii.        Exchange— exchange contents of two registers.

                                                   iv.        Move — copy contents of one memory location to another.

2)    Arithmetic Instructions—addition, subtraction, multiplication, division

3)    Logic and Bit Instructions —perform logical operations

1)     

2)     

3)     

1)     

2)     

3)     

4)    Data test instructions — test contents of a register or memory (to see if zero, negative, etc.), or compare contents of a register to memory (to see if bigger than, etc.)

5)    Jump and Branch Instructions—Change flow of program (e.g., goto, if-then-else, switch-case)

6)    Function Call and Interrupt Instructions— initiate or terminate a subroutine; initiate or terminate and interrupt call

7)    Stacking Instructions — push data onto and pull data off of stack

8)    Stop and Wait Instructions — put HC12 into low power mode

9)    BCD arithmetic, fuzzy logic, minimum and maximum, multiply-accumulate, table interpolation