How to inline x64 asm in vs2017 ?

[Insid3Code]

@vic4key
To avoid the application crash you need to allocate/align the stack...
Compiled and tested (MSVC 2017 15.7.3)

PHP Code:

F1 PROC
  SUB RSP, 40 ; Allocate space on the stack (8 for alignment and 32 for shadow space)...
  PUSH RBP
  MOV RBP, RSP
  LEA RCX, TXT_F1
  CALL puts
  LEAVE
  ADD RSP, 40 ; Cleanup the stack...
  RET
F1 ENDP

F2 PROC
  SUB RSP, 40 ; Allocate space on the stack (8 for alignment and 32 for shadow space)...
  PUSH RBP
  MOV RBP, RSP
  LEA RCX, TXT_F2
  CALL puts
  LEAVE
  ADD RSP, 40 ; Cleanup the stack...
  RET
F2 ENDP 


[vic4key]

Hi Insid3Code. Not used any local variables inside. So the allocation is unnecessary I think. Even it can be shorter. Eg.

F1 PROC
PUSHAD
LEA RCX, TXT_F1
CALL puts
POPAD
F1 ENDP

More, your edited code should be:

F1 PROC
PUSH RBP
MOV RBP, RSP
SUB RSP, 40 ; Allocate space on the stack (8 for alignment and 32 for shadow space); Below of MOV RBP, RSP, this instruction already saved RSP to RBP.
LEA RCX, TXT_F1
CALL puts
LEAVE
ADD RSP, 40 ; Cleanup the stack... ; Not needed. The LEAVE instruction did it.
RET
F1 ENDP

[chants]

Microsoft x64 calling convention

Stack aligned on 16 bytes. 32 bytes shadow space on stack.

Therefore code given here is all non-standards compliant with arbitrary calling convention (compiler will have return address of 8 bytes so an extra 8 indeed is needed but if called from assembler directly, etc assumption may not hold). If not calling back into C code which has been externed for use by the asm code (like puts is for sure), this should obviously not be necessary - neither alignment or shadow space.

PHP Code:

  SUB RSP, 32 ; Allocate space on the stack 32 for shadow space
  AND RSP, -16 ; Align on 16 bytes
…
  LEAVE 


That pattern is needed for both F1 and F2 and its straightforward.