What is the Assembly language?

[raladin]

Inva

[CornedBee]

This has already been answered, but anyway...

Assembly is the second most lowlevel you can get. It's a string representation of the CPU op-codes and thus only a small step away from machine code.

[Scott Slater]

Here's a small assembly language program that will shutdown the system. This works on all win-32 platforms. The program needs to be compiled with MASM32.

;
;
;  Quick Shutdown utility program for Windows 32-bit platforms.
;
;
;  FreeWare by Summit Computer Networks June 4, 2002
;
 
 
.486
.model flat, stdcall
option casemap :none
 
include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\advapi32.inc
 
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\advapi32.lib
 
;=================
; Structures
;=================
    
OSVINFO STRUCT
  dwOSVersionInfoSize   DWORD      ?
  dwMajorVersion        DWORD      ?
  dwMinorVersion        DWORD      ?
  dwBuildNumber         DWORD      ?
  dwPlatformId          DWORD      ?
  szCSDVersion          BYTE 128 dup (?)
OSVINFO ENDS
 
LUIDCUST STRUCT
  usedpart              DWORD      ?
  ignorehigh32bitpart   DWORD      ?
LUIDCUST ENDS
 
TOKEN_PRIVS STRUCT
  privilegecount        DWORD      ?
  theluid               LUIDCUST   <>
  attributes            DWORD      ?
TOKEN_PRIVS ENDS
 
IsWinNt       PROTO
AdjustToken   PROTO
 
; ---------------------
; literal string MACRO
; ---------------------
  literal MACRO quoted_text:VARARG
    LOCAL local_text
    .data
      local_text db quoted_text,0
    .code
    EXITM <local_text>
  ENDM
; --------------------------------
; string address in INVOKE format
; --------------------------------
  SADD MACRO quoted_text:VARARG
    EXITM <ADDR literal(quoted_text)>
  ENDM
      
.data
 
    Msg DB "Shutdown the system now ?",0
    Cap DB "Shutdown",0
 
.code
 
start:
 
    mov eax, MB_ICONQUESTION   ; exclamation dialog
    xor eax, MB_YESNO          ; with a Yes/No Prompt
    xor eax, MB_DEFBUTTON2     ; No is the default
    push eax              ; parameter 4 onto stack
    
    lea eax, Cap          ; address of caption into eax
    push eax              ; caption onto stack
 
    lea eax, Msg          ; address of message into eax
    push eax              ; prompt onto stack
    xor eax, eax          ; zero dialog parent handle ID
    push eax              ; pass it to the stack
    call MessageBoxA      ; show the message box
    cmp eax, IDNO         ; see if the user pressed "NO"
    je BypassBoot         ; if so, bypass the shutdown
 
    call AdjustToken      ; Get rights to restart on NT platforms
    mov eax, 00FFFFh      ; -1 (INT)
    push eax              ; last parameter onto stack
    mov eax , 5           ; 5 (4 or 1)  Force and ShutDown
    push eax              ; first parameter
    call ExitWindowsEx    ; initiate shutdown proceedure
 
BypassBoot:
    xor eax, eax          ; setup zero return value
    push eax              ; pass it to the stack
    call ExitProcess      ; terminate this process
 
 
; *************************************************************************
; Return 1 if the OS is an NT Based Platform, othrwise return 0
IsWinNt proc
 
    LOCAL vi:OSVINFO     ; Version Info Struct
    LOCAL pvi:DWORD      ; Pointer To vi
 
 
    lea eax, vi                         ; vi's address into eax
    mov ecx, SizeOf vi                  ; sizeof vi struct into ecx
    mov (OSVINFO PTR [eax]).dwOSVersionInfoSize, ecx    ; copy size to element
    mov pvi, eax                        ; ptr to vi into pvi
    invoke GetVersionEx,pvi             ; get version API call
    cmp eax, 0                          ; See if we got an error
    je  IsWinNtError
    
    mov eax, pvi                        ; address back into eax
    mov ecx, (OSVINFO PTR [eax]).dwPlatformId  ; Platform ID into ecx
    cmp ecx, VER_PLATFORM_WIN32_NT      ; see if its an NT platform
    je  IsWinNtTrue
 
    mov eax, 0                          ; Return a Zero since its NOT NT
    ret
    
    IsWinNtTrue:
    mov eax, 1                          ; Return 1 since it IS NT
    ret
 
    IsWinNtError:
    mov eax, 2                          ; Return 2 indicating an Error
    
    ret
 
IsWinNt endp
 
; *************************************************************************
; For NT Type Platforms get the privilege for a Shutdown/Restart.
AdjustToken proc
 
    LOCAL hdlProcessHandle:DWORD
    LOCAL hdlTokenHandle:DWORD
    LOCAL tmpLuid:LUIDCUST
    LOCAL tkp:TOKEN_PRIVS
    LOCAL tkpNewButIgnored:TOKEN_PRIVS
    LOCAL lBufferNeeded:DWORD
    LOCAL tBuff[32]:BYTE
    LOCAL ptBuff:DWORD
 
    invoke IsWinNt                 ; see if we're on an NT platform
    cmp eax, 1                     ; a return of 1 means NT platform.
    jne AdjTokDone
 
    invoke GetCurrentProcess       ; get the current process handle
    mov hdlProcessHandle,eax       ; save it to hdlProcessHandle
 
    lea eax, tBuff                 ; address of temp buffer into eax
    mov ptBuff, eax                ; set pointer to temp buffer
    mov BYTE PTR [eax], 0          ; initialize the buffer
 
    invoke OpenProcessToken,hdlProcessHandle,40,ADDR hdlTokenHandle
    invoke LookupPrivilegeValue,ptBuff,SADD("SeShutdownPrivilege"),ADDR tmpLuid
 
    lea eax, tmpLuid               ; address of tmpLuid into eax
 
    ; Contents of tmpLuid into ecx:edx
    mov ecx, (LUIDCUST PTR [eax]).usedpart
    mov edx, (LUIDCUST PTR [eax]).ignorehigh32bitpart
    
    lea eax, tkp                   ; address of tkp into eax
    
    mov (TOKEN_PRIVS PTR [eax]).privilegecount, 1
    mov (TOKEN_PRIVS PTR [eax]).theluid.usedpart, ecx
    mov (TOKEN_PRIVS PTR [eax]).theluid.ignorehigh32bitpart, edx
    mov (TOKEN_PRIVS PTR [eax]).attributes, 2
 
    invoke AdjustTokenPrivileges,hdlTokenHandle,0,ADDR tkp,\
        SizeOf tkpNewButIgnored,ADDR tkpNewButIgnored,ADDR lBufferNeeded
 
    AdjTokDone:
 
    ret
 
AdjustToken endp
 
end start

Enjoy!

[CornedBee]

Although it will work this way, this part

    mov eax, MB_ICONQUESTION   ; exclamation dialog
    xor eax, MB_YESNO          ; with a Yes/No Prompt
    xor eax, MB_DEFBUTTON2     ; No is the default

should actually be

    mov eax, MB_ICONQUESTION   ; exclamation dialog
    or eax, MB_YESNO          ; with a Yes/No Prompt
    or eax, MB_DEFBUTTON2     ; No is the default

using ors instead of xors.

[Scott Slater]

You are correct! I must have been asleep at the wheel when I was doing that part.

[AndySoft]

Requires APM 1.2.

MOV     AX,5301
XOR     BX,BX
INT     15                   ; Connect APM interface
MOV     AX,530E
XOR     BX,BX
MOV     CH,01
MOV     CL,02
INT     15                 ; Enable APM 1.2
MOV     AX,5307
MOV     BX,0001
MOV     CX,0003
INT     15                 ; Turn power off to all BIOS-controlled devices (i.e., turn the PSU off)
MOV     AX,5304
XOR     BX,BX
INT     15               ; If that failed (not APM 1.2?), then disconnect interface
XOR     AX,AX
XOR     BX,BX         ; Clear AX and BX
NOP
NOP
INT     20                ; Go back to DOS

(I think those comments are right.)
I made it in DEBUG. Works fine. I also have one for Suspend, although it won't put the monitor in low-power mode or turn the hard drive back on on my computer...

And to reboot:

JMP    FFFF:0000       ; Reboot NOW!

[Darkwraith]

But (unless I am mistaken) all of those are examples of the 80x86 instruction set.

How bout Z80 and 68000?