5實(shí)驗(yàn)五GNU-ARM裸奔程序設(shè)計(jì)實(shí)驗(yàn)

1、實(shí)驗(yàn)五gnu-arm裸奔程序設(shè)計(jì)【實(shí)驗(yàn)?zāi)康摹縤 了解在linux下編寫(xiě)arm裸奔程序的步驟2掌握gnu下arm匯編程序設(shè)計(jì)的方法3 了解鏈接腳本的作用4 了解 arm-linux-objdump, arm-linux-objcopy 等工具的使用方法【實(shí)驗(yàn)內(nèi)容】1編寫(xiě)匯編程序led.s-閃爍開(kāi)發(fā)板上的led燈2編寫(xiě)鏈接腳本3編寫(xiě)一個(gè)包含多文件的makefileo4燒寫(xiě)到開(kāi)發(fā)板中，運(yùn)行查看情況【實(shí)驗(yàn)步驟】1 led燈的裸奔程序(1) 新建一個(gè)項(xiàng)目目錄：$ mkdir led$ cd led(2) 編寫(xiě)匯編程序文件gedit led.s內(nèi)容如下： text global _start_start:

2、b resetb .b .b .bb .b .b .reset:close dogldr ro,=0x53000000mov rl, #0 str rl, roldr sp,= (0x40000000+4096) extern delay ldr ro,=0x2fff bl _delayset gpf4, 5, 6, 7 output ldr ro,=0x56000050 ldr rl,=0x5500 str rl,roset up offldr ro,=0x56000058 ldr rl,二oxfo;loop:ldr ro,=0x56000054 ldr rl,=0x0 str rl, ro

3、ldr ro,=0x2ffff bl _delayldr ro,=0x56000054 ldr rl,二oxff str rl,roldr ro,=0x2ffff bl delayb loop b .end編寫(xiě)另一匯編文件:gedit delay.s globaldelay tex t_delay:subr0, ro, #1cmpro,#0x0bnedelaymovpc, ir end(3) 編寫(xiě)連接腳本 gedit led.idsoutput_format(elf32-littlearm) output_arch(arm)entry(_start)sections. = 0x00000000

4、;.text:led.o(.text)*(.text).data :*(.data)*(.bss)(4) 編寫(xiě) makefileled.bin:delay.o led.o led .idsarm-linux-ld -tie dds delay.o led.o -o led.elf arm-linux-objcopy -o binary led.elf led.bin delay.o:delay.sarm-linux-gcc -c delay, s o delay.oled.o:led.sarm-linux-gcc -c led.s -o led.o(5) 編譯,得到led.bin燒寫(xiě)到開(kāi)發(fā)板中

5、，查看led燈2調(diào)用c函數(shù)實(shí)驗(yàn)(i)新建另外一個(gè)目錄$ cd$ mkdir boot$ cd boot編輯啟動(dòng)匯編程序start.s text global _start_start:b resetb .b .bb .b .bbreset:設(shè)置sp指針ldr sp,=(0x40000000+4096) 關(guān)閉看門(mén)狗 extern disable watchdog bl disable_watchdog 調(diào)用led_l oop函數(shù) extern led_loop bl led loopb.end(3)編輯c程序init.c#define gpfcon (* (volatile unsigned l

6、ong *)0x56000050) ttdefine gpfdat (* (volatile unsigned long *)0x56000054) ttdefine gpfup (*(volatile unsigned long *)0x56000058) define rwtcon (*(volat訂e unsigned *)0x53000000) void disable_watchdog(void)rwtcon = 0x0;return ;void delay(unsigned long d)int i;for (i=0;i<d;i+);return ;void ledloop(

7、void) gpfcon二gpfc0n&(0xff«8) | (0x55«8);gpfup |= oxfo;wh訂edelay(3000);gpfdat&(oxf«4); delay (3000); gpfdat| = (0xf«4);(4)編寫(xiě)鏈接腳本boot.ldsoutput format(elf32-littlearm)output_arch(arm)entrycstart)sections. = 0x40000000; text: datastart. o(. text) *(. text)： bss* (. data):*(.

8、 bss)(5)編寫(xiě) makefileobjs = start, o init.o boot, bin:$(objs) boot.idsarm-linux-ld -tboot.ids $ (objs) -0 boot.elf arm-1inux-objcopy -0 binary boot, elf boot.bin arm-1inux-objdump -d bootelfbootdis%. o:%. sarm-linux-gcc -nostdlib -c -o $ $<%. 0：%. carm-linux-gcc -nostdlib -c -o $ $<clean:rm -fr /* o /* bin . /* elf . /*