Motorola 24-Bit Digital Signal Processor, DSP56000 manual Return from Subroutine, Rts

INSTRUCTION DESCRIPTIONS

RTS	Return from Subroutine
Operation:	Assembler Syntax:
SSH ➞ PC; SP–1 ➞ SP	RTS

RTS

Description: Pull the program counter (PC) from the system stack. The previous pro- gram counter is lost. The status register (SR) is not affected.

Restrictions: Due to pipelining in the program controller and the fact that the RTS instruction accesses certain controller registers, the RTS instruction must not be immedi-

ately preceded by any of the following instructions:

Immediately before RTS MOVEC to SSH, SSL, or SP

MOVEM to SSH, SSL, or SP

MOVEP to SSH, SSL, or SP

MOVEC from SSH

MOVEM from SSH

MOVEP from SSH

An RTS instruction cannot be the last instruction in a DO loop (at LA).

An RTS instruction cannot be repeated using the REP instruction.

Example:

	:
RTS	;pull PC from system stack
	:

Explanation of Example: The RTS instruction pulls the 16-bit program counter (PC) from the system stack and updates the system stack pointer (SP).

Condition Codes:

15	14	13	12	11		10	9		8	7	6	5	4	3	2	1		0
LF	DM	T	**		S1	S0		I1	I0	S	L	E	U	N	Z		V	C
				MR									CCR

The condition codes are not affected by this instruction.

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