NASM

NASM

Òèï	êîìïèëÿòîð
Îïåðàöèîííàÿ ñèñòåìà	Windows, DOS, Mac OS, Linux
Ïîñëåäíÿÿ âåðñèÿ	2.10 (12 ìàðòà 2012)
Ëèöåíçèÿ	LGPL, ñ âåðñèè 2.07 â óïðîù¸ííàÿ ëèöåíçèÿ BSD
Ñàéò	nasm.us

NASM (Netwide Assembler) â ñâîáîäíûé (LGPL è ëèöåíçèÿ BSD) àññåìáëåð äëÿ àðõèòåêòóðû Intel x86. Èñïîëüçóåòñÿ äëÿ íàïèñàíèÿ 16-, 32- è 64-áèòíûõ ïðîãðàìì.

Èñòîðèÿ

NASM áûë ñîçäàí Ñàéìîíîì Òýòõåìîì ñîâìåñòíî ñ Þëèàíîì Õîëëîì è â íàñòîÿùåå âðåìÿ ðàçâèâàåòñÿ íåáîëüøîé êîìàíäîé ðàçðàáîò÷èêîâ íà SourceForge.net. Ïåðâîíà÷àëüíî îí áûë âûïóùåí ñîãëàñíî åãî ñîáñòâåííîé ëèöåíçèè, íî ïîçæå ýòà ëèöåíçèÿ áûëà çàìåíåíà íà GNU LGPL ïîñëå ìíîæåñòâà ïðîáëåì, âûçâàííûõ âûáîðîì ëèöåíçèè. Íà÷èíàÿ ñ âåðñèè 2.07 ëèöåíçèÿ çàìåíåíà íà «óïðîù¸ííóþ BSD» (BSD èç 2 ïóíêòîâ).

NASM ìîæåò ðàáîòàòü íà ïëàòôîðìàõ, îòëè÷íûõ îò x86, òàêèõ êàê SPARC è PowerPC, îäíàêî êîä îí ãåíåðèðóåò òîëüêî äëÿ x86 è x86-64.

NASM óñïåøíî êîíêóðèðóåò ñî ñòàíäàðòíûì â Linux- è ìíîãèõ äðóãèõ UNIX-ñèñòåìàõ àññåìáëåðîì gas. Ñ÷èòàåòñÿ, ÷òî êà÷åñòâî äîêóìåíòàöèè ó NASM âûøå, ÷åì ó gas. Êðîìå òîãî, àññåìáëåð gas ïî óìîë÷àíèþ èñïîëüçóåò AT&T-ñèíòàêñèñ, îðèåíòèðîâàííûé íà ïðîöåññîðû íå îò Intel, â òî âðåìÿ êàê NASM èñïîëüçóåò âàðèàíò òðàäèöèîííîãî äëÿ x86-àññåìáëåðîâ Intel-ñèíòàêñèñà; Intel-ñèíòàêñèñ èñïîëüçóåòñÿ âñåìè àññåìáëåðàìè äëÿ ïîä DOS/Windows, íàïðèìåð, MASM, TASM, fasm.

Ñèíòàêñèñ ÿçûêà

 NASM èñïîëüçóåòñÿ Intel-ñèíòàêñèñ çàïèñè èíñòðóêöèé. Ïðåäëîæåíèå ÿçûêà àññåìáëåðà NASM (ñòðîêà ïðîãðàììû) ìîæåò ñîñòîÿòü èç ñëåäóþùèõ ýëåìåíòîâ:

Ìåòêà Èíñòðóêöèÿ Îïåðàíäû Êîììåíòàðèé

Îïåðàíäû îòäåëÿþòñÿ ìåæäó ñîáîé çàïÿòîé. Ïåðåä ñòðîêîé è ïîñëå èíñòðóêöèè ìîæíî èñïîëüçîâàòü ëþáîå êîëè÷åñòâî ïðîáåëüíûõ ñèìâîëîâ. Êîììåíòàðèé íà÷èíàåòñÿ ñ òî÷êè ñ çàïÿòîé, à êîíöîì êîììåíòàðèÿ ñ÷èòàåòñÿ êîíåö ñòðîêè.  êà÷åñòâå èíñòðóêöèè ìîæåò èñïîëüçîâàòüñÿ êîìàíäà èëè ïñåâäîêîìàíäà (äèðåêòèâà êîìïèëÿòîðà). Åñëè ñòðîêà î÷åíü äëèííàÿ, òî å¸ ìîæíî ïåðåíåñòè íà ñëåäóþùóþ, èñïîëüçóÿ îáðàòíûé ñëåø \, ïîäîáíî òîìó, êàê ýòî äåëàåòñÿ â ÿçûêå Ñè.

Êîìïèëÿöèÿ è êîìïîíîâêà

NASM êîìïèëèðóåò ïðîãðàììû ïîä ðàçëè÷íûå îïåðàöèîííûå ñèñòåìû â ïðåäåëàõ x86-ñîâìåñòèìûõ ïðîöåññîðîâ. Íàõîäÿñü â îäíîé îïåðàöèîííîé ñèñòåìå, ìîæíî áåñïðåïÿòñòâåííî îòêîìïèëèðîâàòü èñïîëíÿåìûé ôàéë äëÿ äðóãîé.

Êîìïèëÿöèÿ ïðîãðàìì â NASM ñîñòîèò èç äâóõ ýòàïîâ. Ïåðâûé â àññåìáëèðîâàíèå, âòîðîé â êîìïîíîâêà. Íà ýòàïå àññåìáëèðîâàíèÿ ñîçäà¸òñÿ îáúåêòíûé êîä.  í¸ì ñîäåðæèòñÿ ìàøèííûé êîä ïðîãðàììû è äàííûå, â ñîîòâåòñòâèè ñ èñõîäíûì êîäîì, íî èäåíòèôèêàòîðû (ïåðåìåííûå, ñèìâîëû) ïîêà íå ïðèâÿçàíû ê àäðåñàì ïàìÿòè. Íà ýòàïå êîìïîíîâêè èç îäíîãî èëè íåñêîëüêèõ îáúåêòíûõ ìîäóëåé ñîçäà¸òñÿ èñïîëíÿåìûé ôàéë (ïðîãðàììà). Îïåðàöèÿ êîìïîíîâêè ñâÿçûâàåò èäåíòèôèêàòîðû, îïðåäåë¸ííûå â îñíîâíîé ïðîãðàììå, ñ èäåíòèôèêàòîðàìè, îïðåäåë¸ííûìè â îñòàëüíûõ ìîäóëÿõ, ïîñëå ÷åãî âñåì èäåíòèôèêàòîðàì äàþòñÿ îêîí÷àòåëüíûå àäðåñà ïàìÿòè èëè îáåñïå÷èâàåòñÿ èõ äèíàìè÷åñêîå âûäåëåíèå.

Äëÿ êîìïîíîâêè îáúåêòíûõ ôàéëîâ â èñïîëíÿåìûå â Windows ìîæíî èñïîëüçîâàòü ñâîáîäíûé áåñïëàòíî ðàñïðîñòðàíÿåìûé êîìïîíîâùèê alink(äëÿ 64-õ áèòíûõ ïðîãðàìì êîìïîíîâùèê GoLink), à â Linux â êîìïîíîâùèê ld, êîòîðûé åñòü â ëþáîé âåðñèè ýòîé îïåðàöèîííîé ñèñòåìû.

Äëÿ àññåìáëèðîâàíèÿ ôàéëà íóæíî ââåñòè ñëåäóþùóþ êîìàíäó:

nasm -f format filename -o output

Èíñòðóêöèè ïåðåõîäà

Êîìïèëÿòîð îáðàáàòûâàåò òåêñò ïðîãðàììû â íåñêîëüêî ïðîõîäîâ, áëàãîäàðÿ ÷åìó ìîæíî èíñòðóêöèè ïåðåõîäà ðàçìåùàòü äî îáúÿâëåíèÿ ñîîòâåòñòâóþùèõ ìåòîê.

 êîìàíäàõ óñëîâíîãî è áåçóñëîâíîãî (jmp) ïåðåõîäîâ èñïîëüçóåòñÿ ïî óìîë÷àíèþ áëèæíèé òèï ïåðåõîäîâ â near. Ïîýòîìó ïðè âîçìîæíîñòè êîðîòêîãî ïåðåõîäà, ÷òîáû íå çàâûñèòü ðàçìåð ïðîãðàììû íà ëèøíèé áàéò, íåîáõîäèìî ñïåöèàëüíî óêàçàòü òèï ïåðåõîäà short. Ñ âåðñèè 0.98.09b áûëè äîáàâëåíû îïöèè îïòèìèçàöèè -Ox, êîòîðûå ïîçâîëÿþò àâòîìàòè÷åñêè îïòèìèçèðîâàòü ðàçìåð èíñòðóêöèé ïåðåõîäà, â áîëåå ðàííèõ âåðñèÿõ èëè áåç òàêèõ îïöèé ìèíèìàëüíûé ðàçìåð ïðîãðàììû ìîæíî ïîëó÷èòü òîëüêî ðó÷íîé ìîäèôèêàöèåé èñõîäíîãî êîäà.

Ôîðìàò âûõîäíûõ ôàéëîâ

NASM ïîääåðæèâàåò ìíîæåñòâî ôîðìàòîâ âûõîäíûõ ôàéëîâ, ñðåäè íèõ:

• bin â ôàéë ïðîèçâîëüíîãî ôîðìàòà, îïðåäåëÿåìîãî òîëüêî èñõîäíûì êîäîì. Ïðèãîäåí êàê äëÿ ôàéëîâ äàííûõ, òàê è äëÿ ìîäóëåé ñ èñïîëíÿåìûìè êîäàìè â íàïðèìåð, ñèñòåìíûõ çàãðóç÷èêîâ, îáðàçîâ ÏÇÓ, ìîäóëåé îïåðàöèîííûõ ñèñòåì, äðàéâåðîâ .SYS â MS-DOS èëè èñïîëíÿåìûõ ôàéëîâ .COM.
• obj â îáúåêòíûé ìîäóëü â ôîðìàòå OMF, ñîâìåñòèìûé ñ MASM è TASM.
• win32 è win64 â îáúåêòíûé ìîäóëü äëÿ 32- è 64-áèòíîãî êîäà, ñîâìåñòèìûé ñ Win32- è Win64-êîìïèëÿòîðàìè Microsoft.
• aout â îáúåêòíûé ìîäóëü â âàðèàíòå ôîðìàòà a.out, èñïîëüçîâàâøåìñÿ â ðàííèõ Linux-ñèñòåìàõ.
• aoutb â âåðñèÿ ôîðìàòà a.out äëÿ BSD-ñîâìåñòèìûõ îïåðàöèîííûõ ñèñòåì.
• coff â îáúåêòíûé ìîäóëü â ôîðìàòå COFF, ñîâìåñòèìîì ñ êîìïîíîâùèêîì èç DJGPP.
• elf32 è elf64 â îáúåêòíûé ìîäóëü â ôîðìàòàõ ELF32 è ELF64, èñïîëüçóåìûõ â Linux è Unix System V, âêëþ÷àÿ Solaris x86, UnixWare è SCO Unix.

Ôîðìàò âûõîäíîãî ôàéëà ìîæíî çàäàòü ñ ïîìîùüþ êëþ÷à êîìàíäíîé ñòðîêè -f. Ôîðìàòû ìîãóò ðàñøèðÿòü ñèíòàêñèñ íåêîòîðûõ èíñòðóêöèé è äîáàâëÿòü ñîáñòâåííûå èíñòðóêöèè.

Ïðèìåðû ïðîãðàììû Hello, world! ïîä ðàçíûå ÎÑ

Ïðèìåðû ïðîãðàììû Hello, world!, êîòîðàÿ âûâîäèò ñîîòâåòñòâóþùåå ñîîáùåíèå è çàâåðøàåòñÿ.

Ïîä îïåðàöèîííóþ ñèñòåìó DOS

SECTION .text
org 0x100               ; ýòà äèðåêòèâà íóæíà òîëüêî â ñëó÷àå .com ôàéëà, â êîòîðîì íåò íèêàêèõ    ñåêöèé
        mov ah, 0x9
        mov dx, hello
        int 0x21
        mov ax, 0x4c00          ; ah == 0x4c al == 0x00
        int 0x21
SECTION .data
        hello DB "Hello, world!",0xd,0xa,'$'

Ïîä îïåðàöèîííóþ ñèñòåìó Windows (obj)

%include 'WIN32N.INC'
EXTERN MessageBoxA
Import MessageBoxA user32.dll
EXTERN ExitProcess
Import ExitProcess kernel32.dll
SECTION CODE USE32 CLASS=CODE
..start:
        push UINT MB_OK
        push LPCTSTR title
        push LPCTSTR banner
        push HWND NULL
        call [MessageBoxA]
        push UINT NULL
        call [ExitProcess]
SECTION DATA USE32 CLASS=DATA
        banner db 'Hello, world!',0xD,0xA,0
        title db 'Hello',0

Ïîä îïåðàöèîííóþ ñèñòåìó Windows x64 (obj)

; Hello.asm
EXTERN MessageBoxW
EXTERN ExitProcess
SECTION .text USE64
start:
        sub rsp, 28h         ; Microsoft x64 calling convention "shadow space"
        xor rcx, rcx         ; HWND hWnd = NULL
        lea rdx, [banner]    ; LPCTSTR lpText = banner
        lea r8, [title]      ; LPCTSTR lpCaption = title
        xor r9, r9           ; UINT uType =  MB_OK
        call MessageBoxW     ; MessageBox(hWnd, lpText, lpCaption, uType)
        xor rcx, rcx         ; UINT uExitCode = 0
        call ExitProcess     ; ExitProcess(uExitCode)
SECTION .data
        banner dw __utf16__('Hello, world!'),0
        title dw __utf16__('Hello!'),0

>nasm -f win64 Hello.asm
>golink Hello.obj kernel32.dll user32.dll

Ïîä îïåðàöèîííóþ ñèñòåìó Linux

SECTION .data
msg     db "Hello, world!",0xa  
len     equ $ - msg
SECTION .text
global _start           ; the program entry point
_start:
        mov eax, 4      ; 'write' syscall
        mov ebx, 1      ; file descr. 1 (stdout)
        mov ecx, msg    ; pointer to the data
        mov edx, len    ; amount of data
        int 0x80        ; call to the kernel
        mov eax, 1      ; '_exit' syscall
        mov ebx, 0      ; zero exit code (success)
        int 0x80        ; call to the kernel

Ïîä îïåðàöèîííóþ ñèñòåìó FreeBSD

SECTION .data
msg     db "Hello, world!",0xa  
len     equ $ - msg
SECTION .text
global _start            ; the program entry point
_start:
        push dword len
        push dword msg
        push dword 1     ; 1 is the file descriptor of stdout
        mov eax, 4       ; 4 is the 'write' syscall
        push eax         ; we must leave an extra dword on the stack
        int 0x80         ; call to the kernel
        add esp, 16      ; clean up the stack
        push dword 0     ; 0 is the exit code (success)
        mov eax, 1       ; 1 is the '_exit' syscall
        push eax         ; extra dword on the stack
        int 0x80         ; call to the kernel
                         ; no cleanup - we will never return

Ïîä îïåðàöèîííóþ ñèñòåìó KolibriOS

bits 32
     %include 'mos.inc'
     section .text
     MOS_HEADER01 main,image_end,memory_end,stacktop,0,0
main:
redraw:
       call draw_window
wait_event:
        MOS_WAITEVENT
        dec eax
        jz redraw
        dec eax
        jz key
;button pressed; we have only one button, close
        MOS_EXIT
key:
;key pressed, read it and ignore
        mov eax, MOS_SC_GETKEY
        int 0x40
        jmp wait_event
draw_window:
        MOS_STARTREDRAW
        xor eax, eax
        mov ebx, 10*65536 + 150
        mov ecx, 40*65536 + 50
        mov edx, 0x33FFFFFF
        mov edi, header
        int 0x40 ;define&draw window
        mov eax, MOS_SC_WRITETEXT
        mov ebx, 30*65536 + 10
        mov ecx, 0x80000000
        mov edx, string
        int 0x40 ;display string
        MOS_ENDREDRAW
        ret
        section .data
header db 'HelloWorld test',0
string db 'Hello, World!',0
image_end:
        section .bss
alignb 4
stack resb 1024
stacktop:
memory_end:

Èçâåñòíûå ïðîãðàììû, íàïèñàííûå íà NASM

• Asmutils â íàáîð ñèñòåìíûõ óòèëèò äëÿ îïåðàöèîííûõ ñèñòåì BSD, UnixWare, Solaris è AtheOS.
• Ïðîåêò AsmOS â îïåðàöèîííàÿ ñèñòåìà íà àññåìáëåðå NASM (ñåé÷àñ íà ñòàäèè ðàçðàáîòêè).

Ëèòåðàòóðà

• Ðóäîëüô Ìàðåê. Àññåìáëåð íà ïðèìåðàõ. Áàçîâûé êóðñ. â ÑÏá.: Íàóêà è òåõíèêà, 2005. â 240 ñ. â ISBN 5-94387-232-9
• À. Â. Ñòîëÿðîâ. Ïðîãðàììèðîâàíèå íà ÿçûêå àññåìáëåðà NASM äëÿ ÎÑ Unix. â Ì.: ÌÀÊÑ Ïðåññ, 2011. â 188 ñ. â ISBN 978-5-317-03627-0

Ññûëêè

• Îôèöèàëüíûé ñàéò
• Ïðîåêò NASM íà ñàéòå SourceForge.net
• Ðàñøèðåííûé àññåìáëåð: NASM
• Ââåäåíèå â NASM (íèçêîóðîâíåâîå ïðîãðàììèðîâàíèå äëÿ Windows)