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Motorola Book E Implementation Standards: APU ID Reference

MOTOROLA

Introduction

Introduction

1.1

Introduction

The e500 Application Binary Interface (ABI), and possibly other ABIs, provide a mechanism for specifying

the types and revisions of APUs that are required for proper behavior of a program. This information is

contained in an optional .PPC.EMB.apuinfo section in the ELF-format object file. This document

provides the official mapping between Motorola Book E Implementation Standard APUs and the numeric

APU IDs that are used in the APUinfo section. See “APU Information Section” in Chapter 3, “Object Files,”

of the PowerPC e500 Application Binary Interface, for more details on the format and usage of this section.

1.2

Motivation

The APU information is intended primarily to allow link-time checks of compatibility between object files

to avoid obvious errors. For example, because both AltiVec and the signal processing engine (SPE) APU use

the same instruction encodings for different instructions, linking an object file that requires AltiVec

instructions with an object file that requires SPE instructions should provide an error message.

The APU information can also be used by disassemblers to unambiguously disassemble such shared

opcodes. In addition, operating systems can use the APUinfo section in an application to provide transparent

emulation of APUs that are not present in the hardware. Without APU information, an operating system

would not know whether it should emulate AltiVec or SPE semantics for certain instruction encodings.

1.3

Implementation

The APUinfo section contains an entry for each APU that the object file requires. Each entry contains a

32-bit word: an upper 16-bit half word specifying the APU type, and a lower 16-bit half word specifying the

revision of that APU. This document presents the current assignments for the APU types. See the reference

manual for the implementation to determine the revision of an APU for the lower half word of the entry.

Table 1-1 provides the current APU ID assignments. Note that this application note is the definitive source

for APU ID assignments and will be revised as new APUs are added.

Table 1-1. APU IDs

APU ID (16 Bits)

APU

0x0000–0x003E

Reserved for legacy use

0x003f

0x0040

Book E integer select (isel) APU

0x0041Motorola Book E performance monitor APU

0x0042

Motorola Book E machine check APU

0x0043

Motorola Book E cache locking APU

0x0044–0x00FF

Reserved

0x0100

Motorola Book E SPE APU

0x0101

Motorola Book E SPFP APU

0x0102

e500 branch-locking APU (also called the BTB locking APU)

0x0102–0xFFFF

Reserved

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