1997, MASM fully supported Windows 95 and included some AMD-specific instructions. In 1999, Intel released macros for SIMD and 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. 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 Object module formats supported by MASM Early versions of MASM generated object modules using the OMF format, which was used to create binaries for MS-DOS or OS/2. Since version 6.1, MASM is able to produce object modules in the Portable Executable (PE/COFF) format. PE/COFF is compatible with recent Microsoft C compilers, and object modules produced by either MASM or the C compiler can be routinely intermixed and linked into Win32 and Win64 binaries. Assemblers compatible with MASM Some other assemblers can assemble most code written for MASM, with the exception of more complex macros. Turbo Assembler (TASM) developed by Borland, later owned by Embarcadero, last updated in 2002, but still supplied with C++Builder and RAD Studio. JWasm Macro Assembler, licensed under the Sybase Open Watcom EULA. Last updated in 2014. Pelle's Macro Assembler, a component of the Pelles C development environment. UASM is a free MASM-compatible assembler based on JWasm. ASMC is a free MASM-compatible assembler based on JWasm. Mixed language programming support Documentation for 1987's version 5.1 included support for "Microsoft BASIC, C, FORTRAN, Pascal." See also Microsoft MACRO-80 Assembly language High-level assembler Comparison of assemblers References External links Intro to MASM Win32 Masm32 project 1981 software Assemblers Microsoft development tools DOS software Programming tools for Windows