Motorola DSP56000 manual 5.3.6 I/O Short, Implicit Reference, Addressing Modes Summary

INSTRUCTION FORMATS

	EXAMPLE: MOVE Y:$5432,B0
			BEFORE EXECUTION
	B2		B1				B0
	55	48 47		24			23	0
	X X		X X X X X X			X X X X X X
7		0	23	0			23	0
					23 Y MEMORY 0
			$5432				A B C D E F

Assembler Syntax: XXXX or aa

Memory Spaces: P:

Additional Instruction Execution Time (Clocks): 2

Additional Effective Address Words: 1

			AFTER EXECUTION
	B2		B1			B0
	55	48 47		24 23		0
	X X		X X X X X X		A B C D E F
7		0	23	0	23	0
					23	Y MEMORY 0
			$5432		A B C D E F

Figure 6-8 Special Addressing – Absolute Addressing

6.3.5.3.5Absolute Short

The address of the operand occupies six bits in the instruction operation word, allowing addresses $0000–$003F to be accessed (see Figure 6-11). Classified as both a memory reference and program reference, the address is zero extended to 16 bits when used to address an operand or program memory.

6.3.5.3.6I/O Short

Classified as a memory reference, the I/O short addressing mode is similar to absolute short addressing. The address of the operand occupies six bits in the instruction operation word. I/O short is used with the bit manipulation and MOVEP instructions. The I/O short address is ones extended to 16 bits to address the I/O portion of X and Y memory (addresses $FFC0–$FFFF – see Figure 6-12).

6.3.5.3.7Implicit Reference

Some instructions make implicit reference to PC, SS, LA, LC, or SR. For example, the jump instruction (JMP) implicitly references the PC; whereas, the repeat next instruction (REP) implicitly references LC. The registers implied and their uses are defined by the individual instruction descriptions (see APPENDIX A - INSTRUCTION SET DETAILS).

6.3.5.4Addressing Modes Summary

MOTOROLA INSTRUCTION SET INTRODUCTION 6 - 17