摘自 ARM 程序分析与设计 王宇行
1.在 C 中声明函数原型,并加extern 关键词
extern int num;
exitern int sqr(int i);
2.在汇编中,用EXPROT 导出函数名,并用该函数名作为汇编代码段的标志
EXPORT sqr
EXPORT num
- 1. AREA |.text|,CODE,READONLY
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2. IMPORT Relacation
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3. EXPORT sqr
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4. EXPORT num
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5. ldr r5,=Relacation
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6. sqr
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7. MUL R1,R0,R0 ;R1=R0*R0
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8. MOV R0,R1 ;R0=R1
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9. MOV PC,LR ;return R0
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10. AREA |.data|,NOINIT,READWRITE
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11. data SPACE 1024
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12. END
- 1. #include<stdio.h>
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2. extern int num;
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3. extern int sqr(int i)
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4.
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5. int Relocation=0;
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6. int main(void)
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7. {
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8. printf("square of %d is %d\n",num,sqr(num));
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9. }
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