The file asm-intel.lang can be used to provide syntax highlighting for Intel assembly in gedit.
Note that the file uses version 2 of the language definition file format, which works with GtkSourceView 2, 3 and 4. See here for details. The file is based on this version 1 implementation.
To use asm-intel.lang, copy it to your GtkSourceView folder. For example, for GtkSourceView 4, you would use this command:
sudo cp asm-intel.lang /usr/share/gtksourceview-4/language-specs/