ARM VERSION 1.2 manual 5 MAR, MRA, For current processors, Are general-purpose registers

ARM Instruction Reference

4.8.5MAR, MRA

XScale coprocessor 0 instructions.

Transfer between two general-purpose registers and a 40-bit internal accumulator.

Syntax

MAR{cond} Acc, RdLo, RdHi

MRA{cond} RdLo, RdHi, Acc

where:
cond	is an optional condition code (see Conditional execution on page 4-4).
Acc	is the internal accumulator. The standard name is accx, where x is an
	integer in the range 0-n. The value of n depends on the processor. It is 0
	for current processors.
RdLo, RdHi	are general-purpose registers.

Usage

The MAR instruction copies the contents of RdLo to bits[31:0] of Acc, and the least significant byte of RdHi to bits[39:32] of Acc.

The MRA instruction:

•copies bits[31:0] of Acc to RdLo

•copies bits[39:32] of Acc to RdHi

•sign extends the value by copying bit[39] of Acc to bits[31:8] of RdHi.

Architectures

These instructions are only available in XScale.

Examples

MAR acc0,r0,r1

MRA r4,r5,acc0

MARNE acc0,r9,r2

MRAGT r4,r8,acc0

ARM DUI 0068B Copyright © 2000, 2001 ARM Limited. All rights reserved. 4-77