NASM
A clean macro assembler used heavily for x86/x86-64 tutorials, kernels, boot code, and standalone assembly projects.
LinuxWindowsmacOS via object outputx86x86-64
Books
NASM x86-64 Practical BookBoot Code with NASMNASM and C Interop Manual
Assembly workbench
MASM, NASM, GAS, and Clang integrated assembler
Compare syntax, object formats, ABI integration, platform behavior, and the books/labs each assembler deserves.
Assembler desks
MASM
The Microsoft assembler family for Windows ABI work, Win64 procedures, COFF objects, PDB-oriented workflows, and MSVC integration.
Windowsx86x86-64ARM64 through Microsoft toolchain context
Books
MASM for Windows x64Win64 ABI Assembly NotesMASM and MSVC Integration
GNU Assembler GAS
The GNU assembler used inside GCC/binutils pipelines and cross-compilers, essential for Linux, embedded, RISC-V, and OS development.
LinuxBSDmacOS toolchain variantsembeddedx86-64ARM64RISC-Vmany GNU targets
Books
GAS for Linux SystemsRISC-V Assembly with GASARM64 GNU Assembly Notes
Clang Integrated Assembler
The assembler built into Clang/LLVM pipelines, important for modern cross-platform builds, inline assembly, LLD, and LLVM diagnostics.
WindowsLinuxmacOSembedded LLVM targetsx86-64ARM64RISC-VWebAssemblyLLVM targets
Books
Clang Assembly WorkflowsLLVM MC Layer NotesInline Assembly Across Platforms