36. CALL – Long Call to a Subroutine
36.1. Description
Calls to a subroutine within the entire Program memory. The return address (to the instruction after the
CALL) will be stored onto the Stack. (See also RCALL). The Stack Pointer uses a post-decrement
scheme during CALL.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i) PC ← k Devices with 16-bit PC, 128KB Program memory maximum.
(ii) PC ← k Devices with 22-bit PC, 8MB Program memory maximum.
Syntax: Operands: Program Counter: Stack:
(i) CALL k 0 ≤ k < 64K PC ← k STACK ← PC+2
SP ← SP-2, (2 bytes,
16 bits)
(ii) CALL k 0 ≤ k < 4M PC ← k STACK ← PC+2
SP ← SP-3 (3 bytes,
22 bits)
32-bit Opcode:
1001 010k kkkk 111k
kkkk kkkk kkkk kkkk
36.2. Status Register (SREG) and Boolean Formula
I T H S V N Z C
– – – – – – – –
Example:
mov r16,r0 ; Copy r0 to r16
call check ; Call subroutine
nop ; Continue (do nothing)
...
check: cpi r16,$42 ; Check if r16 has a special value
breq error ; Branch if equal
ret ; Return from subroutine
...
error: rjmp error ; Infinite loop
Words 2 (4 bytes)
Cycles 4 devices with 16-bit PC
Atmel AVR Instruction Set Manual [OTHER]
Atmel-0856L-AVR-Instruction-Set-Manual_Other-11/2016
63
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