TOS

TOS

Top-of-Stack Register

Contents of the stack pointed to by the STKPTR register. This is the value that will be loaded into the Program Counter upon a RETURN or RETFIE instruction.

Notes: The individual bytes in this multibyte register can be accessed with the following register names:
  • TOSU: Accesses the upper byte TOS[20:16]
  • TOSH: Accesses the high byte TOS[15:8]
  • TOSL: Accesses the low byte TOS[7:0]
  0x4FD 24  

TOS

Bit  23 22 21 20 19 18 17 16  
        TOS[20:16]  
Access        R/W R/W R/W R/W R/W  
Reset        0 0 0 0 0  
Bit  15 14 13 12 11 10 9 8  
  TOS[15:8]  
Access  R/W R/W R/W R/W R/W R/W R/W R/W  
Reset  0 0 0 0 0 0 0 0  
Bit  7 6 5 4 3 2 1 0  
  TOS[7:0]  
Access  R/W R/W R/W R/W R/W R/W R/W R/W  
Reset  0 0 0 0 0 0 0 0  

Bits 20:0 – TOS[20:0]: Top-of-Stack

Top-of-Stack