用老师代码反汇编结果与老师的反汇编代码不同

为啥我用老师的代码反汇编结果与老师的反汇编代码不同？
led.c

• int main()
• {
• unsigned int *pGPFCON = (unsigned int *)0x56000050;
• unsigned int *pGPFDAT = (unsigned int *)0x56000054;
• /* 配置GPF4为输出引脚 */
• *pGPFCON = 0x100;
• /* 设置GPF4输出0 */
• *pGPFDAT = 0;
• return 0;
• }
  

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start.S

• .text
• .global _start
• _start:
• /* 设置内存: sp 栈 */
• ldr sp, =4096 /* nand启动 */
• // ldr sp, =0x40000000+4096 /* nor启动 */
• /* 调用main */
• bl main
• halt:
• b halt
• 
  

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我的反汇编

• led.elf: file format elf32-littleARM
• Disassembly of section .text:
• 00000000 <_start>:
• 0: e3a0da01 mov sp, #4096 ; 0x1000
• 4: eb000000 bl c
• 00000008 :
• 8: eafffffe b 8
• 0000000c
  :
• c: e52db004 push {fp} ; (str fp, [sp, #-4]!)
• 10: e28db000 add fp, sp, #0 ; 0x0
• 14: e24dd00c sub sp, sp, #12 ; 0xc
• 18: e3a03456 mov r3, #1442840576 ; 0x56000000
• 1c: e2833050 add r3, r3, #80 ; 0x50
• 20: e50b300c str r3, [fp, #-12]
• 24: e3a03456 mov r3, #1442840576 ; 0x56000000
• 28: e2833054 add r3, r3, #84 ; 0x54
• 2c: e50b3008 str r3, [fp, #-8]
• 30: e51b200c ldr r2, [fp, #-12]
• 34: e3a03c01 mov r3, #256 ; 0x100
• 38: e5823000 str r3, [r2]
• 3c: e51b2008 ldr r2, [fp, #-8]
• 40: e3a03000 mov r3, #0 ; 0x0
• 44: e5823000 str r3, [r2]
• 48: e3a03000 mov r3, #0 ; 0x0
• 4c: e1a00003 mov r0, r3
• 50: e28bd000 add sp, fp, #0 ; 0x0
• 54: e8bd0800 pop {fp}
• 58: e12fff1e bx lr
  

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老师的反汇编

• led.elf: file format elf32-littlearm
• Disassembly of section .text:
• 00000000 <_start>:
• 0: e3a0da01 mov sp, #4096 ; 0x1000
• 4: eb000000 bl c
• 00000008 :
• 8: eafffffe b 8
• 0000000c
  :
• c: e1a0c00d mov ip, sp
• 10: e92dd800 stmdb sp!, {fp, ip, lr, pc}
• 14: e24cb004 sub fp, ip, #4 ; 0x4
• 18: e24dd008 sub sp, sp, #8 ; 0x8
• 1c: e3a03456 mov r3, #1442840576 ; 0x56000000
• 20: e2833050 add r3, r3, #80 ; 0x50
• 24: e50b3010 str r3, [fp, #-16]
• 28: e3a03456 mov r3, #1442840576 ; 0x56000000
• 2c: e2833054 add r3, r3, #84 ; 0x54
• 30: e50b3014 str r3, [fp, #-20]
• 34: e51b2010 ldr r2, [fp, #-16]
• 38: e3a03c01 mov r3, #256 ; 0x100
• 3c: e5823000 str r3, [r2]
• 40: e51b2014 ldr r2, [fp, #-20]
• 44: e3a03000 mov r3, #0 ; 0x0
• 48: e5823000 str r3, [r2]
• 4c: e3a03000 mov r3, #0 ; 0x0
• 50: e1a00003 mov r0, r3
• 54: e24bd00c sub sp, fp, #12 ; 0xc
• 58: e89da800 ldmia sp, {fp, sp, pc}
  

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