Editing Microsoft Macro Assembler (section)

==History==
The earliest versions of MASM date back to 1981.<ref name = "InfoWorld Jan 1985">{{Cite magazine | last = Watt | first = Peggy |author2=Christine McGeever | title = Macintosh Vs. IBM PC At One Year |magazine= InfoWorld | volume = 7 | issue = 1 | pages =15–16 | date = January 7, 1985 | url = https://books.google.com/books?id=-i4EAAAAMBAJ&pg=PA16 | issn = 0199-6649}} The IBM PC Macro Assembler was released in December 1981.</ref> They were sold either as the generic "Microsoft Macro Assembler" for all x86 machines or as the OEM version specifically for [[IBM PC]]s. By Version 4.0, the [[IBM]] release was dropped. Up to Version 3.0, MASM was also bundled with a smaller companion assembler, ASM.EXE. This was intended for PCs with only 64k of memory and lacked some features of the full MASM, such as the ability to use code macros.

MS-DOS versions up to 4.x included Microsoft's LINK utility, which was designed to convert intermediate [[Relocatable Object Module Format|OBJ file]]s generated by MASM and other compilers; however, as users who did not program had no use of the utility, it was moved to their compiler packages.

Version 4.0, released October 1985, added support for [[i286|286]] instructions.

Version 5.0, released August 1987, supported [[i386|386]] instructions, and also shorthand mnemonics for segment descriptors (.code, .data, etc.), but it could still only generate real mode executables.

Through version 5.0, MASM was available as an [[MS-DOS]] application only. Versions 5.1 and 6.0 were available as both [[MS-DOS]] and [[OS/2]] applications.<ref name = "InfoWorld Apr 1991">{{Cite magazine | last = Marshall | first = Martin | title = Macro Assembler Update Adds High-Level Features |magazine= InfoWorld | volume = 13 | issue = 17 | page =21 | date = April 29, 1991 | url = https://books.google.com/books?id=y1AEAAAAMBAJ&pg=PT20 | issn = 0199-6649}}</ref>

Version 6.0, released in 1991, added parameter passing with "invoke" and some other high level-like constructs, in addition to the already existing high level-like [[record (computer science)|record]]s, among other things. Both 6.0 and 6.0B were able to be run on an [[8086]] processor but could generate flat 32-bit 386 code.  In 1992, 6.1 was released, which added support for the COFF object format used by [[Windows NT]], and removed support for OS/2.  6.1 was built as a bi-modal binary before the [[Win32 API]] was finalized, and is incompatible with running on Windows NT due to missing exports.<ref name="Microsoft KB Q94314">{{cite web |title=Q94314: 32-Bit Flat Memory Model MASM Code for Windows NT |url=https://jeffpar.github.io/kbarchive/kb/094/Q94314/ |url-status=dead |archive-url=https://web.archive.org/web/20210113091943/https://jeffpar.github.io/kbarchive/kb/094/Q94314/ |archive-date=13 January 2021 |access-date=3 October 2023}}</ref>

In 1993 full support for protected mode 32-bit applications and the [[Intel P5 (microarchitecture)|Pentium]] instruction set was added. The 6.11 MASM binary at that time (1993) was shipped as a "bi-modal" (win32, i.e. [[Portable Executable|PE]]) DOS-extended binary (using the [[Phar Lap (company)|Phar Lap]] TNT DOS extender). However, the setup.exe is an MZ executable so won't run under 64-bit versions of Windows, and the bi-modal ml.exe is [[file compression|compressed]], and the decomp.exe is an NE executable, so also won't run under 64-bit versions of Windows, so you effectively need access to 32-bit Windows (or MSDOS) in order to install it. Version 6.11 is the last version of MASM that will run under MS-DOS. There were a series of [[Patch (computing)|patches]] available, up to 6.11d, that need 32-bit Windows to run, but the patched ml.exe still has the Phar Lap dos extender so can still be run under MSDOS.

By the end of 1997, MASM fully supported [[Windows 95]] and included some [[AMD]]-specific instructions.<ref name="harvey">{{cite web |author=R. E. Harvey |year=2007 |title=Assemblers |url=http://ourworld.compuserve.com/homepages/r_harvey/doc_book.htm |url-status=dead |archive-url=https://web.archive.org/web/20080216121237/http://ourworld.compuserve.com/homepages/r_harvey/doc_book.htm |archive-date=16 February 2008 |access-date=4 February 2010}}</ref>

In 1999, Intel released macros for [[SIMD]] and [[MMX (instruction set)|MMX]] instructions, which were shortly thereafter supported natively by MASM. With the 6.15 release in 2000, Microsoft discontinued support for MASM as a separate product, instead subsuming it into the [[Visual Studio]] toolset. Though it was still compatible with [[Windows 98]], current versions of Visual Studio were not.<ref name="harvey" /> Support for 64-bit processors was not added until the release of [[Visual Studio 2005]], with MASM 8.0.

After 25 June 2015, there are at least three different MASMs with the version number 14.00.23026. In Microsoft Visual Studio 2015 Enterprise Edition, there is one "amd64_x86" ml and two ml64s, "x86_amd64" and "amd64". They run on different platforms targeting different platforms:
* amd64_x86: generates 64-bit code, runs in a Windows 32-bit environment
* x86_amd64: generates 32-bit code, runs in a Windows 64-bit environment
* amd64:     generates 64-bit code, runs in a Windows 64-bit environment