VAX Macro

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VAX Macro is the computer assembly language implementing the instruction set for the line of CPUs designed to run the OpenVMS operating system created by Digital Equipment Corporation in 1977. OpenVMS now belongs to Hewlett-Packard.

The original version of VAX Macro was called Macro-11 and implemented the RSX-11 instruction set. The 32-bit version of VAX Macro was called Macro-32 and natively supported the entire line of VAX/VMS (now known as OpenVMS) processors developed and manufactured by Digital Equipment Corporation with some minor differences in the instruction set (especially in the area of CPU flags) depending on the exact VAX/VMS processor. (Digital advanced and enhanced several different VAX CPUs over the life of the VAX/VMS hardware architecture but burned essentially the same instruction set into them all).

With the advent of the 64-bit Alpha AXP chip, VAX Macro essentially became VMS Macro. Macro-32 was supported on the Alpha architecture, but because the Alpha utilized RISC technology and therefore a RISC instruction set, Macro-32 was no longer the native instruction set implementation; Macro-32 was actually implemented then as a compiler under the Alpha architecture.

The Alpha AXP chips introduced to the VMS world then the latest progression of the VMS Macro language, supporting the underlying RISC instruction set, and was called Macro-64.