PROC

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 PROCdistance⟧ ⟦language-type⟧ ⟦ PUBLIC | PRIVATE | EXPORT ⟧ ⟦<prologuearg>⟧ ⟦USES reglist⟧ ⟦, parameter:tag⟧ ...⟧
FRAME:ehandler-address⟧ ⟧
statements
label ENDP

Remarks

The ⟦distance⟧ and ⟦language-type⟧ arguments are valid only in 32-bit MASM.

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
MASM BNF Grammar