Microsoft Macro Assembler

Website: docs.microsoft.com/en-us/cpp/assembler/masm/microsoft-macro-assembler-reference

The Microsoft Macro Assembler (MASM) is an x86 assembler that uses the Intel syntax for MS-DOS and Microsoft Windows.

Beginning with MASM 8.0, there are two versions of the assembler: One for 16-bit & 32-bit assembly sources, and another (ML64) for 64-bit sources only.

MASM is maintained by Microsoft, but since version 6.12 it has not been sold as a separate product.

It is instead supplied with various Microsoft SDKs and C compilers.

Recent versions of MASM are included with Microsoft Visual Studio.

Notable applications compiled using MASM are RollerCoaster Tycoon which was 99% written in assembly and built with MASM.