The Definitive Guide to x86 64

Inside the book

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• 2 The Definitive Guide to x86-64 A System’s Journey from Power-On to Application x86-64 ISA and Platform Reference A bit‑by‑bit system journey and reference — explaining every step from power‑on to application execution, based directly on the Intel® 64 and AMD64 official manuals. Ayman Alheraki May 7, 2026 Contents Prelude: The Genesis of the x86-64 Platform 2 Author’s Introduction 2 Historical Context and Design Philosophy 4 The Evolutionary Path: 8086 to x86-64 (IA-32e) . . . . . . . . . . . . . . . . . . 4 The 16-bit Foundation: 8086 and 80286 . . . . . . . . . . . . . . . . . . . . 4 32-bit Revolution: 80386 and IA-32 . . . . . . . . . . . . . . . . . . . . . . 5 The 64-bit Extension: AMD64 and Intel 64 (IA-32e) . . . . . . . . . . . . 5 Feature Evolution within x86-64 . . . . . . . . . . . . . . . . . . . . . . . . 6 AMD64 vs. Intel 64: Compatibility and Divergence . . . . . . . . . . . . . . . . 6 Historical Adoption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Identical Core Architectural State . . . . . . . . . . . . . . . . . . . . . . . 6 Differences in Model-Specific Registers and Hardware Support . . . . . . . 7 The von Neumann Model and the x86-64 Realization . . . . . . . . . . . . . . . 7 Mapping the von Neumann Model onto x86-64 . . . . . . . . . . . . . . . . 8 Deviation from Pure von Neumann: Cache Hierarchy . . . . . . . . . . . . 8 Fundamental Design Principles: CISC, Microcode, and Beyond . . . . . . . . . 9 From CISC to Internal RISC . . . . . . . . . . . . . . . . . . . . . . . . . 9 Microcode and Macro-Fusion . . . . . . . . . . . .