UNIX System V Application Binary Interface January 2000 Order Number: 245370-001 THIS DOCUMENT IS PROVIDED “AS IS” WITH NO WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY, NONINFRINGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. Information in this document is provided in connection with Intel products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Intel's Terms and Conditions of Sale for such products, Intel assumes no liability whatsoever, and Intel disclaims any express or implied warranty, relating to sale and/or use of Intel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. 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Copyright © Intel Corporation, 2000 *Third-party brands and names are the property of their respective owners. Contents 1Introduction 1-1 1.1 The Intel IA-64 Architecture and the System V ABI......................................................1-1 1.2 How to Use the System V ABI for Intel IA-64 Processors ............................................1-1 1.3 Evolution of the ABI Specification.................................................................................1-2 1.4 Additional Documents...................................................................................................1-2 2 Software Installation 2-1 3 Low-level System Information 3-1 3.1 Introduction ...................................................................................................................3-1 3.2 Machine Interface .........................................................................................................3-1 3.2.1 Fundamental Types......................................................................................3-1 3.3 Operating System Interface ..........................................................................................3-2 3.3.1 Exception Interface.......................................................................................3-2 3.3.2 Signal Delivery..............................................................................................3-4 3.3.3 Signal Handler Interface ...............................................................................3-5 3.3.3.1Signal Delivery – Implementation Notes............................................................3-5 3.3.4 Debugging Support.......................................................................................3-6 3.3.5 Process Startup ............................................................................................3-6 4 Object Files 4-1 4.1 ELF Header ..................................................................................................................4-1 4.1.1 Machine Information .....................................................................................4-1 4.1.1.1Programming Model ..........................................................................................4-1 4.1.1.2File Class ...........................................................................................................4-1 4.1.1.3Data Encoding ...................................................................................................4-1 4.1.1.4Operating System Identification.........................................................................4-1 4.1.1.5Processor Identification .....................................................................................4-2 4.1.1.6Processor-Specific Flags ...................................................................................4-2 4.2 Sections ........................................................................................................................4-3 4.2.1 Section Types...............................................................................................4-3 4.2.2 Section Attribute Flags .................................................................................4-4 4.2.3 Special Sections...........................................................................................4-4 4.2.4 Architecture Extensions................................................................................4-6 4.3 Relocations...................................................................................................................4-6 4.3.1 Relocation Types..........................................................................................4-6 5 Program Loading and Dynamic Linking 5-1 5.1 Program Header ...........................................................................................................5-1 5.2 Program Loading ..........................................................................................................5-1 5.2.1 Link-Time and Run-Time Addresses ............................................................5-4 5.2.2 Initializations.................................................................................................5-4 5.3 Dynamic Linking ...........................................................................................................5-4 5.3.1 Dynamic Linker.............................................................................................5-4 5.3.2 Dynamic Section...........................................................................................5-5 5.3.3 Shared Object Dependencies.......................................................................5-5 5.3.4 Global Offset Table.......................................................................................5-6 5.3.5 Function Addresses......................................................................................5-6 UNIX System V Application Binary Interface iii 5.3.6 Procedure Linkage Table .............................................................................5-7 5.3.7 Initialization and Termination Functions .....................................................5-10 6Libraries 6-1 7 Miscellaneous 7-1 7.1 Introduction...................................................................................................................7-1 7.2 Development Environment ...........................................................................................7-1 7.2.1 Pre-Defined Preprocessor Symbols .............................................................7-1 7.2.2 Pre-Defined Preprocessor Assertions ..........................................................7-1 7.2.3 Compiler Pragmas........................................................................................7-2 7.3 ILP32 ABI .....................................................................................................................7-2 7.3.1 Objectives of the 32-bit Little-endian Runtime Architecture..........................7-3 7.3.2 Changes from the 64-bit Software Conventions...........................................7-3 7.3.3 Addressing and Protection ...........................................................................7-3 7.3.4 Data Allocation .............................................................................................7-4 7.3.4.1Global Variables ................................................................................................7-4 7.3.5 Local Memory Stack Variables.....................................................................7-4 7.3.6 Parameter Passing.......................................................................................7-4 Figures 3-1 Double-Extended (80-bit) Floating-point Formats .....................................................................3-2 4-1 Instruction Bundle Layout ..........................................................................................................4-7 4-2 Relocatable Fields .....................................................................................................................4-8 5-1 Example Executable File ...........................................................................................................5-2 5-2 Example Program Header Segments........................................................................................5-2 5-3 Example Process Image Segments ..........................................................................................5-3 5-4 Procedure Linkage Table Sample Entries .................................................................................5-8 Tables 3-1 Additional Fundamental Data Types .........................................................................................3-1