Assembly-Language Comments
Instructions in an __asm block can use assembly-language comments:
__asm mov ax, offset buff ; Load address of buff
Because C macros expand into a single logical line, avoid using assembly-language comments in macros. (See Defining __asm Blocks as C Macros.) An __asm block can also contain C-style comments; for more information, see Using C or C++ in __asm Blocks.