diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index b0c77db..eb6c3b2 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt*	For Vim version 9.1.  Last change: 2024 Nov 10
+*syntax.txt*	For Vim version 9.1.  Last change: 2024 Dec 12
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -883,12 +883,15 @@
 extensions.  Therefore you will have to select the type yourself, or add a
 line in the assembly file that Vim will recognize.  Currently these syntax
 files are included:
-	asm		GNU assembly (the default)
+	asm		GNU assembly (usually have .s or .S extension and were
+			already built using C compiler such as GCC or CLANG)
 	asm68k		Motorola 680x0 assembly
 	asmh8300	Hitachi H-8300 version of GNU assembly
 	ia64		Intel Itanium 64
 	fasm		Flat assembly (http://flatassembler.net)
-	masm		Microsoft assembly (probably works for any 80x86)
+	masm		Microsoft assembly (.masm files are compiled with
+			Microsoft's Macro Assembler. This is only supported
+			for x86, x86_64, ARM and AARCH64 CPU families)
 	nasm		Netwide assembly
 	tasm		Turbo Assembly (with opcodes 80x86 up to Pentium, and
 			MMX)
diff --git a/runtime/filetype.vim b/runtime/filetype.vim
index fe12047..cac7c2c 100644
--- a/runtime/filetype.vim
+++ b/runtime/filetype.vim
@@ -1,7 +1,7 @@
 " Vim support file to detect file types
 "
 " Maintainer:	The Vim Project <https://github.com/vim/vim>
-" Last Change:	2024 Nov 24
+" Last Change:	2024 Dec 12
 " Former Maintainer:	Bram Moolenaar <Bram@vim.org>
 
 " Listen very carefully, I will say this only once
@@ -183,8 +183,15 @@
 
 " Assembly (all kinds)
 " *.lst is not pure assembly, it has two extra columns (address, byte codes)
+" *.[sS], *.[aA] usually Assembly - GNU
 au BufNewFile,BufRead *.asm,*.[sS],*.[aA],*.mac,*.lst	call dist#ft#FTasm()
 
+" Assembly - Netwide
+au BufNewFile,BufRead *.nasm			setf nasm
+
+" Assembly - Microsoft
+au BufNewFile,BufRead *.masm			setf masm
+
 " Assembly - Macro (VAX)
 au BufNewFile,BufRead *.mar			setf vmasm