.RESTOREXMM128

Generates either a WOD_SAVE_XMM128 or a WOD_SAVE_XMM128_FAR Unwind Version 3 unwind code entry for the specified XMM register and offset using the current epilogue offset.

Syntax

.RESTOREXMM128 xmmreg, offset

Parameters

xmmreg
The XMM register to restore.

offset
The stack offset from which the register is restored. Must be a multiple of 16.

Remarks

Important

This directive is experimental and is subject to change. Enable Unwind Version 3 with ml64.exe /unwindv3.

.RESTOREXMM128 is only valid in Unwind Version 3. It's the epilogue counterpart to .SAVEXMM128.

Microsoft Assembler (MASM) chooses the most efficient encoding for a given offset.

• .RESTOREXMM128 is only allowed within an epilogue region, between .BEGINEPILOG and .ENDEPILOG.
• These directives generate unwind metadata (.xdata and .pdata sections) but don't produce executable code.
• In Unwind Version 3, .RESTOREXMM128 must appear before the instruction that loads the XMM register from the stack.
• To ensure agreement, wrap both the unwind directives and the code they're meant to unwind in a macro.
• In Unwind Version 3, epilogue directives are mandatory for epilogue unwind code generation. No epilogue unwind codes are emitted without a .BEGINEPILOG/.ENDEPILOG pair.

Note

In Unwind Version 1, the directive appears after the corresponding instruction. In Unwind Version 3, the directive appears before the instruction.

Example for unwindv3

; ml64 /unwindv3 ex1.asm /link /entry:Example1 /SUBSYSTEM:CONSOLE
_text SEGMENT
Example1 PROC FRAME
   .allocstack 030h
   sub rsp, 030h
   .savexmm128 xmm6, 0
   movdqa [rsp], xmm6
   .savexmm128 xmm7, 010h
   movdqa [rsp+010h], xmm7
.endprolog
   ; rest of function ...
   .beginepilog
   .restorexmm128 xmm7, 010h
   movdqa xmm7, [rsp+010h]
   .restorexmm128 xmm6, 0
   movdqa xmm6, [rsp]
   .freestack 030h
   add rsp, 030h
   .endepilog
   ret
Example1 ENDP
_text ENDS
END

See also

x64 Unwind Version 3 (experimental)
Directives Reference
.SAVEXMM128
.BEGINEPILOG
MASM BNF Grammar