Texas Instruments TMS320C2XX User Manual

Page 234

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Load Auxiliary Register

LAR

7-81

Assembly Language Instructions

Description

The contents of the specified data-memory address or an 8-bit or 16-bit con-
stant are loaded into the specified auxiliary register (ARx). The specified con-
stant is acted upon like an unsigned integer, regardless of the value of SXM.

The LAR and SAR (store auxiliary register) instructions can be used to load
and store the auxiliary registers during subroutine calls and interrupts. If an
auxiliary register is not being used for indirect addressing, LAR and SAR en-
able the register to be used as an additional storage register, especially for
swapping values between data-memory locations without affecting the con-
tents of the accumulator.

Words

Words

Addressing mode

1

Direct, indirect or

short immediate

2

Long immediate

Cycles for a Single LAR Instruction (Using Direct and Indirect Addressing)

Program

Operand

ROM

DARAM

SARAM

External

DARAM

2

2

2

2+p

code

SARAM

2

2

2, 3

†

2+p

code

External

2+d

src

2+d

src

2+d

src

3+d

src

+p

code

† If the operand and the code are in the same SARAM block

Cycles for a Repeat (RPT) Execution of an LAR Instruction (Using Direct

and Indirect Addressing)

Program

Operand

ROM

DARAM

SARAM

External

DARAM

2n

2n

2n

2n+p

code

SARAM

2n

2n

2n, 2n+1

†

2n+p

code

External

2n+nd

src

2n+nd

src

2n+nd

src

2n+1+nd

src

p

code

† If the operand and the code are in the same SARAM block

Cycles for a Single LAR Instruction (Using Short Immediate Addressing)

ROM

DARAM

SARAM

External

2

2

2

2+p

code

Cycles for a Single LAR Instruction (Using Long Immediate Addressing)

ROM

DARAM

SARAM

External

2

2

2

2+2p

Cycles

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