How the stack frame works in ML64.

[hutch--]

Arkdasm has proven a very useful toy.

From a procedure coded as follows.

; ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤

msgloop proc

    setstack

    LOCAL msg   :MSG

    LOCAL64 _rsi                ; allocate QWORD
    LOCAL64 _rdi                ; allocate QWORD

    mov _rsi, rsi               ; preserve rsi
    mov _rdi, rdi               ; preserve rdi

    xor rsi, rsi                ; zero rsi
    lea rdi, msg                ; load rdi with structure address
    jmp get_msg                 ; jump into loop

  lpstart:
    void(TranslateMessage,rdi)
    void(DispatchMessage,rdi)
  get_msg:
    test rax, function(GetMessage,rdi,rsi,rsi,rsi)
    jnz lpstart

    mov rdi, _rdi               ; restore rdi
    mov rsi, _rsi               ; restore rsi

    ret

msgloop endp

; ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤


This is the disassembly of the separate message loop proc I have been testing. It shows how the stack frame is created using ENTER and LEAVE. You will note that the above procedure has a simple MACRO "setstack" that writes a QWORD local at the start of the procedure. It occurs at no additional cost in terms of mnemonics and effectively automates procedures without having to mess around with direct stack adjustments.


; --------------------------------------------------------------------------
; sub_1400011f0
; --------------------------------------------------------------------------
sub_1400011f0   proc
enter 0x70, 0x0
mov qword ptr [0x140003046], rsi
mov qword ptr [0x14000304e], rdi
xor rsi, rsi
lea rdi, [rbp-0x38]
jmp 0x14000121d

0x14000120b:
mov rcx, rdi
call qword ptr [TranslateMessage]
mov rcx, rdi
call qword ptr [DispatchMessageA]

0x14000121d:
mov rcx, rdi
mov rdx, rsi
mov r8, rsi
mov r9, rsi
call qword ptr [GetMessageA]
test rax, rax
jne 0x14000120b
mov rdi, qword ptr [0x14000304e]
mov rsi, qword ptr [0x140003046]
leave
ret
sub_1400011f0   endp


It would appear that ML64 is not as crude or toothless as some of our friends would have us believe.  :P