PROC

 

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Marks start and end of a procedure block called label. The statements in the block can be called with the CALL instruction or INVOKE directive.

Syntax

  
   label PROC [[distance]] [[langtype]] [[visibility]] [[<prologuearg>]]   
[[USES reglist]] [[, parameter [[:tag]]]]...  
[FRAME [:ehandler-address] ]  
statements  
label ENDP  

Remarks

[FRAME [:ehandler-address] ] is only valid with ml64.exe, and causes MASM to generate a function table entry in .pdata and unwind information in .xdata for a function's structured exception handling unwind behavior.

When the FRAME attribute is used, it must be followed by an .ENDPROLOG directive.

See MASM for x64 (ml64.exe) for more information on using ml64.exe.

Example

; ml64 ex1.asm /link /entry:Example1 /SUBSYSTEM:CONSOLE  
_text SEGMENT  
Example1 PROC FRAME  
   push r10  
.pushreg r10  
   push r15  
.pushreg r15  
   push rbx  
.pushreg rbx  
   push rsi  
.pushreg rsi  
.endprolog  
   ; rest of function ...  
   ret  
Example1 ENDP  
_text ENDS  
END  

The above code will emit the following function table and unwind information:

FileHeader->Machine 34404  
Dumping Unwind Information for file ex2.exe  
  
.pdata entry 1 0x00001000 0x00001023  
  
  Unwind data: 0x00002000  
  
    Unwind version: 1  
    Unwind Flags: None  
    Size of prologue: 0x08  
    Count of codes: 3  
    Frame register: rbp  
    Frame offset: 0x0  
    Unwind codes:  
  
      Code offset: 0x08, SET_FPREG, register=rbp, offset=0x00  
      Code offset: 0x05, ALLOC_SMALL, size=0x10  
      Code offset: 0x01, PUSH_NONVOL, register=rbp  

See Also

Directives Reference