TMS320F datasheet(86/389 Pages) TI

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Immediate Addressing Mode

6-2

6.1

Immediate Addressing Mode

In the immediate addressing mode, the instruction word contains a constant

to be manipulated by the instruction. The two types of immediate addressing

modes are:

- Short-immediate addressing. Instructions that use short-immediate ad-

dressing have an 8-bit, 9-bit, or 13-bit constant as an operand. Short-im-

mediate instructions require a single instruction word, with the constant

embedded in that word.

- Long-immediate addressing. Instructions that use long-immediate ad-

dressing have a 16-bit constant as an operand and require two instruction

words. The constant is sent as the second instruction word. This 16-bit val-

ue can be used as an absolute constant or as a 2s-complement value.

In Example 6–1, the immediate operand is contained as a part of the RPT

instruction word. For this RPT instruction, the instruction register will be loaded

with the value shown in Figure 6–1. Immediate operands are preceded by the

symbol #.

Example 6–1. RPT Instruction Using Short-Immediate Addressing

RPT #99

;Execute the instruction that follows RPT

;100 times.

Figure 6–1. Instruction Register Contents for Example 6–1

8-bit constant = 99

RPT opcode for immediate addressing

TMS320F Datasheet(PDF) 86 Page - Texas Instruments