Generates either a UWOP_SAVE_XMM128 or a UWOP_SAVE_XMM128_FAR unwind code entry for the specified XMM register and offset using the current prologue offset. MASM will choose the most efficient encoding.
.SAVEXMM128 allows ml64.exe users to specify how a frame function unwinds, and is only allowed within the prologue, which extends from the PROC FRAME declaration to the .ENDPROLOG directive. These directives do not generate code; they only generate .xdata and .pdata. .SAVEXMM128 should be preceded by instructions that actually implement the actions to be unwound. It is a good practice to wrap both the unwind directives and the code they are meant to unwind in a macro to ensure agreement.
offset must be a multiple of 16.
For more information, see MASM for x64 (ml64.exe).