Denote x64 architecture

concurrency-primer.tex

@@ -572,7 +572,15 @@ \section{Atomic operations as building blocks}
 \section{Sequential consistency on weakly-ordered hardware}
 
 Different hardware architectures offer distinct memory models or \introduce{memory models}.
-For instance, x64 architecture is known to be \introduce{strongly-ordered},
+For instance, x64 architecture\punckern\footnote{%
+Also known as x86-64, x64 is a 64-bit extension of the x86 instruction set, officially unveiled in 1999.
+This extension heralded the introduction of two novel operation modes:
+64-bit mode for leveraging the full potential of 64-bit processing and compatibility mode for maintaining support for 32-bit applications.
+Initially developed by AMD and publicly released in 2000, the x64 architecture has since been adopted by Intel and VIA,
+signaling a unified industry shift towards 64-bit computing.
+This wide adoption marked the effective obsolescence of the Intel Itanium architecture (IA-64),
+despite its initial design to supersede the x86 architecture.
+} is known to be \introduce{strongly-ordered},
 generally ensuring a global sequence for loads and stores in most scenarios.
 Conversely, architectures like \textsc{Arm} are considered \introduce{weakly-ordered},
 meaning one should not expect loads and stores to follow the program sequence without explicit instructions to the \textsc{CPU}.