ÀÌ ¼½¼Ç¿¡¼´Â gcc inline assembly¿¡¼ ½ÇÁ¦ assembly¸¦ Àû´Â ºÎºÐ (¾ÕÀ¸·Î´Â ÀÌ ºÎºÐÀ» asms¶ó°í ºÎ¸£°Ú½À´Ï´Ù)¿¡ ´ëÇØ ¼³¸íÇÕ´Ï´Ù.
asmsÀÇ ³»¿ëÀº ±×´ë·Î ÄÄÆÄÀÏ µÈ assembly¿Í ÇÔ²² gasmÀ¸·Î ³Ñ¾î°¡¹Ç·Î gasmÀÇ ¹®¹ýÀ» µû¶ó¾ß ÇÕ´Ï´Ù. GasmÀº target ÀÎÀÚ°¡ µÚ¿¡¿À´Â AT&T ¹®¹ýÀ» µû¸£¸ç instruction »çÀÌÀÇ ±¸ºÐÀº ¼¼¹ÌÄÝ·ÐÀ̳ª °³Ç๮ÀÚ·Î ÇÏ°í ·¹Áö½ºÅ͵éÀº %registerÀÇ ÇüÅ·ΠǥÇöÇÕ´Ï´Ù. ix86 °è¿ÀÇ ´ëºÎºÐÀÇ ¾î¼Àºí·¯¿Í intel manualÀº target ÀÎÀÚ°¡ ¾Õ¿¡¿À´Â intel ¹®¹ýÀ» µû¸£°í ÀÖÀ¸¹Ç·Î manualÀ» º¸°Å³ª ´Ù¸¥ ¾î¼Àºí·¯ÀÇ Äڵ带 º¼ ¶§ ÁÖÀÇÇϽñ⠹ٶø´Ï´Ù. ´õ ÀÚ¼¼ÇÑ ³»¿ëÀº gasm ¸Þ´º¾ó°ú intel processor manualÀ» ÂüÁ¶Çϼ¼¿ä.
Gcc°¡ »ý¼ºÇÏ´Â assembly ÄÚµå´Â ½Éº¼ Á¤ÀǵîÀ» Á¦¿ÜÇϰí´Â ¸ðµÎ ÅÇ Çϳª¸¸Å µé¿©¾²±â°¡ µÇ¾îÀÖ½À´Ï´Ù. Inline assembly´Â #APP¿Í #NO APP»çÀÌ¿¡ µé¾î°¡´Âµ¥ ÅÇ Çϳª¸¸Å µé¿©¾²±â°¡ µÈ »óÅ¿¡¼ ¹®ÀÚ¿ÀÌ ±×´ë·Î µé¾î°©´Ï´Ù. µû¶ó¼ Assembly outputÀ» Àб⠽±°Ô Çϱâ À§ÇØl¼± °¢ instructionµé »çÀ̸¦ \n\t·Î ±¸ºÐÇØÁÖ¸é µË´Ï´Ù.
__asm__ __volatile__("line1\n\tline2\line3"); |
À» ÄÄÆÄÀÏÇϸé
#APP line1 line2 line3 #NO_APP |
°¡ µË´Ï´Ù. ±×·±µ¥ ³»¿ëÀÌ ¸¹¾ÆÁö¸é À§Ã³·³ ÇÑ ÁÙ·Î Àû±â°¡ Èûµé¾îÁý´Ï´Ù. ±×·± °æ¿ì¿£ ¾Æ·¡Ã³·³ ÇÏ¸é µË´Ï´Ù.
__asm__ __volatile__( "pushl %%ebp # comment \n\t" "movl %%esp, %%eax \n\t" "cli" \n\t" "incl %0 \n\t" "movl %8, %%esp \n\t" "sti" \n\t" "pushl %%eax \n\t" "call *%7 \n\t" "cli \n\t" "decl %0 \n\t" "popl %%esp # comment 2 \n\t" "sti \n\t" "popl %%ebp " : "=m" (processor0->intr_lv), "=&a" (a), "=b" (b), "=c" (c), "=d" (d), "=D" (D), "=S" (S) : "m" (jmpaddr), "g" (processor0->bh_stack_top)); |
ÄÄÆÄÀÏ Çϸé,
#APP pushl %ebp # comment movl %esp, %eax cli incl processor0+20 movl processor0+76, %esp sti pushl %eax call *-40(%ebp) cli decl processor0+20 popl %esp # comment 2 sti popl %ebp #NO_APP |
Gasm¿¡¼ Ä¿¸àÆ®´Â #ºÎÅÍ ±× ÁÙÀÇ ³¡±îÁöÀ̸ç inline assembly¿¡¼µµ °°Àº ¹æ¹ýÀ¸·Î ¾µ ¼ö ÀÖ½À´Ï´Ù.
À§ÀÇ ¿¹¿¡¼ %%eax, %%esp°°Àº °ÍµéÀ» º¼ ¼ö Àִµ¥ %%´Â ½ÇÁ¦ output¿¡¼ % Çϳª¸¦ Ãâ·ÂÇÕ´Ï´Ù. ƯÁ¤ ·¹Áö½ºÅ͸¦ ½á¾ßÇÒ ¶§´Â %nÀ¸·Î Á¤ÇØÁ൵ µÇÁö¸¸ input, output ÁöÁ¤¿¡¼ ¾²°í ½ÍÀº ·¹Áö½ºÅ͸¦ ÁöÁ¤ÇÏ°í ¾îÂ÷ÇÇ ±× ·¹Áö½ºÅͰ¡ ÇÒ´çµÉ °ÍÀ» ¾Ë°í ÀÖÀ¸¹Ç·Î %%register¸¦ ¾²´Â °ÍÀÌ ´õ ÀÐ°í ¾²±â ÆíÇÕ´Ï´Ù.
ÇÑ °¡Áö ÁÖÀÇÇÒ Á¡Àº ¸¸¾à input, outputÀÌ Çϳªµµ ¾ø´Â °æ¿ì¿¡´Â asms¿¡ ´ëÇÑ ÀÎÀÚġȯÀÌ ÀüÇô ÀϾÁö ¾Ê°í %%µµ %·Î ¹Ù²îÁö ¾Ê½À´Ï´Ù. Áï, input, outputÀÌ ¸ðµÎ ¾øÀ» ¶§´Â %%register´ë½Å %register¶ó°í ÇØ¾ßÇÕ´Ï´Ù.
ÇÔ¼ö¸¦ assembly·Î Á¤ÀÇÇØ¾ßÇÏ´Â °æ¿ì´Â ÁÖ·Î ÇÔ¼öÀÇ entry³ª exitÀÌ CÀÇ convention°ú ´Þ¶ó¼ CÇÔ¼ö ¾È¿¡¼ inline assembly·Î ¸¸µé ¼ö ¾ø´Â °æ¿ìÀÔ´Ï´Ù. ¹°·Ð µû·Î ¾î¼Àºí¸® ÈÀÏÀ» ¸¸µé¾îµµ µÇÁö¸¸ ÀÌ·± ÇÔ¼ö°¡ ¸î °³ µÇÁö ¾ÊÀ» ¶§´Â ¹ø°Å·Ó±â ¶§¹®¿¡ inline assembly·Î ¸¸µå´Â °ÍÀÌ ´õ ÆíÇÕ´Ï´Ù.
¶Ç, assembly·Î ¸¸µç ÇÔ¼ö¿¡¼ C ÇÁ·Î±×·¥¿¡¼ ¾²´ø Àü¿ªº¯¼ö, ¸ÅÅ©·ÎµîÀ» ¾²°ÔµÇ´Â °æ¿ì°¡ Àִµ¥, ÀϹÝÀûÀÎ °æ¿ì assembly ¼Ò½º¸¦ C preprocessor·Î ó¸®ÇÏ°í ¸µÅ©ÇÏ¸é µÇÁö¸¸ Àü¿ªÀ¸·Î ¼±¾ðµÈ structure¸¦ »ç¿ëÇÏ·Á¸é ¹®Á¦°¡ µË´Ï´Ù. ½ºÅ©¸³µåµîÀ» »ç¿ëÇØ¼ memberµéÀÇ offsetÀ» Æ÷ÇÔÇÑ Çì´õÈÀÏÀ» ¸¸µç ÈÄ C preprocessor¸¦ »ç¿ëÇÏ¸é °¡´ÉÇϱä ÇÏÁö¸¸ (½ÇÁ¦·Î freebsd Ä¿³Î¿¡¼± ÀÌ ¹æ¹ýÀ» »ç¿ëÇÕ´Ï´Ù) »ó´çÈ÷ ±ÍÂúÀº ÀÏÀÌ µÇ¹ö¸³´Ï´Ù. ÀÌ·± °æ¿ì¿¡µµ inline assembly·Î ÇÔ¼ö¸¦ Á¤ÀÇÇØ ÁÖ´Â °ÍÀÌ ÈξÀ °£ÆíÇÕ´Ï´Ù.
AsmsÀÇ ³»¿ëÀÌ output¿¡ ±×´ë·Î Ãâ·ÂµÇ±â ¶§¹®¿¡ ½Éº¼À» Á¤ÀÇÇÏ´Â directiveµµ »ç¿ëÇÒ ¼ö ÀÖ½À´Ï´Ù. ¿ì¼± ¿¹¸¦ º¸°Ú½À´Ï´Ù.
struct { int a; int b; } mine = { 0, 0 }; int iasm_test_func(int arg); static int iasm_test_func2(void); static void __iasm_function_dummy(void) { __asm__ __volatile__( ".globl iasm_test_func \n\t" "iasm_test_func: \n\t" "pushl 4(%%esp) \n\t" "pushl %2 \n\t" "pushl %1 \n\t" "pushl %0 \n\t" "call printf \n\t" "addl $16, %%esp \n\t" "ret " : : "i" ("hello world.. mine.a=%d mine.b=%d arg=%d\n"), "g" (mine.a), "g" (mine.b)); __asm__ __volatile__( "iasm_test_func2: \n\t" "pushl $32 \n\t" "call iasm_test_func \n\t" "addl $4, %esp "); } int main(void) { mine.a = 123; mine.b = 321; iasm_test_func(16); return iasm_test_func2(); } |
¿ì¼± Á¤ÀÇÇÒ µÎ ÇÔ¼öÀÇ prototypeÀ» º¼ ¼ö ÀÖ½À´Ï´Ù. iasm_test_func2´Â staticÀÎ °É ÁÖÀÇÇØ¼ º¸½Ã±â ¹Ù¶ø´Ï´Ù.
Inline assembly´Â ÇÔ¼ö¹Û¿¡¼´Â ¾²ÀÏ ¼ö ¾øÀ¸¹Ç·Î __iasm_function_dummy¶ó´Â ÇÔ¼ö¸¦ ¸¸µé°í ±× ¾ÈÀÇ µÎ inline assembly¿¡¼ °¢°¢ ÇÔ¼ö¸¦ Á¤ÀÇÇß½À´Ï´Ù. ù¹øÂ° ÇÔ¼ö´Â iasm_test_func·Î ½Éº¼ Á¤ÀÇ ¹Ù·ÎÀ§ÀÇ .globl directive·Î ¸µÅ©½Ã ¿ÜºÎ¿¡ º¸ÀÌ´Â ½Éº¼ÀÓÀ» ¾Ë·ÁÁÖ¾ú°í µÎ¹øÂ°ÀÇ iasm_test_func2ÇÔ¼ö´Â .globlÀÌ ¾øÀ¸¹Ç·Î ¸µÅ©½Ã ¿ÜºÎ¿¡¼ º¸ÀÌÁö ¾Ê´Â static ÇÔ¼ö°¡ µË´Ï´Ù.
Gcc´Â ÄÄÆÄÀÏ ÇÒ ¶§ iasm_test_func2°¡ inline assembly¾È¿¡ Á¤ÀǵǾî ÀÖ´Â °É ¾ËÁö ¸øÇϹǷΠstaticÇÔ¼ö°¡ Á¤ÀǵÇÁö ¾Ê¾Ò´Ù°í °æ°í¸¦ ÇÏÁö¸¸ ¹«½ÃÇÏ¸é µË´Ï´Ù.
iasm_test_func´Â Á¤¼ö ÀÎÀÚ¸¦ Çϳª ¹Þ°í, Àü¿ª ±¸Á¶Ã¼ÀÎ mineÀÇ ³»¿ë°ú ¹ÞÀº ÀÎÀÚÀÇ °ªÀ» printf¸¦ »ç¿ëÇØ Ãâ·ÂÇÏ´Â ÇÔ¼ö ÀÔ´Ï´Ù. Inline assembly¸¦ º¸¸é inputÀ¸·Î format ¹®ÀÚ¿, mine.a, mine.b°¡ »ç¿ëµÇ´Âµ¥ "i"´Â immediate integer operand·Î format ¹®ÀÚ¿ÀÇ ½ÃÀÛ ÁÖ¼Ò°¡ ±×´ë·Î operand°¡ µË´Ï´Ù. "g"´Â immediate, ¹ü¿ë ·¹Áö½ºÅÍ ¶Ç´Â memory operand¸¦ ¶æÇÏ´Â °ÍÀ¸·Î compiler°¡ ÀûÀýÈ÷ ¼±ÅÃÇÕ´Ï´Ù.
iasm_test_func2´Â iasm_test_func(32)¸¦ È£ÃâÇÏ´Â ÇÔ¼öÀÔ´Ï´Ù.
À§ÀÇ ÇÁ·Î±×·¥À» ÄÄÆÄÀÏÇÏ¸é ¾Æ·¡¿Í °°Àº assembly°¡ µË´Ï´Ù. (gcc -fomit-frame-pointer -mpreferred-stack-boundary=2 -O2 -S iasm_function.c)
.file "iasm_function.c" .version "01.01" gcc2_compiled.: .globl mine .data .align 4 .type mine,@object .size mine,8 mine: .long 0 .long 0 .section .rodata .align 32 .LC0: .string "hello world.. mine.a=%d mine.b=%d arg=%d\n" .text .align 4 .type __iasm_function_dummy,@function __iasm_function_dummy: #APP .globl iasm_test_func iasm_test_func: pushl 4(%esp) pushl mine+4 pushl mine pushl $.LC0 call printf addl $16, %esp ret iasm_test_func2: pushl $32 call iasm_test_func addl $4, %esp #NO_APP ret .Lfe1: .size __iasm_function_dummy,.Lfe1-__iasm_function_dummy .align 4 .globl main .type main,@function main: movl $123,mine movl $321,mine+4 pushl $16 call iasm_test_func call iasm_test_func2 addl $4,%esp ret .Lfe2: .size main,.Lfe2-main .ident "GCC: (GNU) 2.95.4 20010902 (Debian prerelease)" |
__iasm_function_dummy¾È¿¡ µÎ °³ÀÇ inline assembly°¡ #APP, #NOAPP ¾È¿¡¼ iasm_test_func, iasm_test_func2¸¦ Á¤ÀÇÇϰí ÀÖ°í, iasm_test_funcÀÇ %1, %2´Â direct addressingÀ¸·Î ó¸®µÈ °ÍÀ» º¼ ¼ö ÀÖ½À´Ï´Ù.