CPU Architecture Roadmap

Reading order, official sources only, x86-64 → ARM64. Five stages: registers and flags first, assembly practice in parallel, then the ABI, then the reference volumes, then ARM64.

OFFICIAL DOCS ONLY · INTEL SDM · AMD APM · ARM
Stage 1 · Registers + flags Stage 2 · Assembly practice Stage 3 · The ABI Stage 4 · Reference volumes Stage 5 · ARM64 Rule of thumb
Stage 1 registers + flags Stage 2 asm practice in parallel Stage 3 calling convention + stack Stage 4 reference volumes Stage 5 ARM64 use, don’t read after x86-64 feels natural
The path: Stages 1 and 2 run together, then ABI → references → ARM64.

1 x86-64 registers + flags start here

Intel SDM (Software Developer’s Manual) GUIDE

Official page, free PDFs: intel.com — Intel SDM

Volume 1: Basic Architecture — read these chapters only, in order:

ChapterTitleWhy
Ch 3Basic Execution EnvironmentGPRs, RIP, RFLAGS. Core of what you asked
Ch 4Data Types—
Ch 6Procedure Calls, Interrupts, Exceptionsstack mechanics
Don’t read Vol 1 cover-to-cover. ~100 pages total from these chapters.

Alternative many find it more readable

AMD64 Architecture Programmer’s Manual, Volume 1: Application Programming (doc #24592)
amd.com — developer guides & manuals

2 Intel-syntax assembly practice parallel with Stage 1

NASM manual NASM = Intel syntax by default

nasm.us/doc — Ch 2–3, then write tiny Linux programs

Toolchain setup

nasm -f elf64 x.asm && ld x.o     # assemble/run
gdb  →  set disassembly-flavor intel
objdump -d -M intel ./a.out

Practice loops

3 Calling convention + stack the ABI

System V AMD64 psABI official spec

gitlab.com/x86-psABIs/x86-64-ABI — build/download PDF from repo

Read §3.2 only: registers, argument passing, stack frame, red zone.

4 x86-64 reference volumes use, don’t read

DocRole
SDM Volume 2 REFERENCEfull instruction set A–Z. Keep open while reversing
SDM Volume 3 REFERENCEonly when you go OS-level: Ch 2–4 (protection, paging), interrupts

5 ARM64 after x86-64 feels natural

In this order:

#DocNotes
1 ARM Cortex-A Series Programmer’s Guide for ARMv8-A (DEN0024A) GUIDE
developer.arm.com/documentation/den0024		 the readable intro, ~300 pages. Ch 4 registers, Ch 5–6 A64 instruction set, Ch 9 ABI
2 Learn the Architecture — A64 ISA guide
developer.arm.com/documentation/102374		 short, modern
3 AAPCS64
github.com/ARM-software/abi-aa/releases → aapcs64.pdf		 ARM’s calling convention, = ARM’s psABI
4 ARM ARM (DDI 0487) REFERENCE
developer.arm.com/documentation/ddi0487		 12,000+ page reference. Lookup only, never linear

6 Rule of thumb

2 types of docs: guides (read linearly: SDM Vol 1 chapters, DEN0024A) and references (SDM Vol 2/3, ARM ARM — open on second monitor).
Practice ratio: 1 hour reading → 2 hours writing/reversing asm.
You know Stage 1 is done when you can explain every flag ZF/SF/CF/OF after a cmp + why jle fires.
Part of notes-goblin 🧌 · original note created 2026-09-16