62. ICALL – Indirect Call to Subroutine
62.1. Description
Calls to a subroutine within the entire 4M (words) 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: Comment:
(i) PC(15:0) ← Z(15:0) Devices with 16-bit PC, 128KB Program memory maximum.
(ii) PC(15:0) ← Z(15:0)
PC(21:16) ← 0
Devices with 22-bit PC, 8MB Program memory maximum.
Syntax: Operands: Program Counter: Stack:
(i) ICALL None See Operation STACK ← PC + 1
SP ← SP - 2 (2 bytes,
16 bits)
(ii) ICALL None See Operation STACK ← PC + 1
SP ← SP - 3 (3 bytes,
22 bits)
16-bit Opcode:
1001 0101 0000 1001
62.2. Status Register (SREG) and Boolean Formula
I T H S V N Z C
– – – – – – – –
Example:
mov r30,r0 ; Set offset to call table
icall ; Call routine pointed to by r31:r30
Words 1 (2 bytes)
Cycles 3 devices with 16-bit PC
4 devices with 22-bit PC
Cycles XMEGA
®
2 devices with 16-bit PC
3 devices with 22-bit PC
Atmel AVR Instruction Set Manual [OTHER]
Atmel-0856L-AVR-Instruction-Set-Manual_Other-11/2016
98
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