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AIX Version 4.3 Assembler Language Reference

ecowx (External Control Out Word Indexed) Instruction

Purpose

Translates the effective address (EA) to a real address and sends the real address and the contents of a register to a controller.

Note: The ecowx instruction is defined only in the PowerPC architecture and is an optional instruction. It is supported on the PowerPC 601 RISC Microprocessor, PowerPC 603 RISC Microprocessor, and PowerPC 604 RISC Microprocessor.

Syntax

ecowx RS,RA,RB

Description

The ecowx instruction translates EA to a real address and sends the real address and the content of general-purpose register RS to a controller. If RA = 0, the EA is the content of RB, otherwise EA is the sum of the content of RA plus the content of RB.

If EAR(E) = 1, a store request for the real address corresponding to EA is sent to the controller identified by EAR(RID), bypassing the cache. The content of RS is sent with the store request.

Notes:
  1. EA must be a multiple of 4 (a word-aligned address); otherwise, the result is boundedly undefined.
  2. The operation is treated as a store to the addressed byte with respect to protection.

Parameters

RS Specifies target general-purpose register where result of operation is stored.
RA Specifies source general-purpose register for operation.
RB Specifies source general-purpose register for operation.

Related Information

The eciwx (External Control In Word Indexed) instruction.

Processing and Storage

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