The NASM 2 series support x86-64, and is the production version of NASM
since 2007.
+\S{cl-2.10} Version 2.10
+
+\b When optimization is enabled, \c{mov r64,imm} now optimizes to the
+ shortest form possible between:
+
+\c mov r32,imm32 ; 5 bytes
+\c mov r64,imm32 ; 7 bytes
+\c mov r64,imm64 ; 10 bytes
+
+To force a specific form, use the \c{STRICT} keyword, see \k{strict}.
+
\S{cl-2.09.09} Version 2.09.09