Mixed programming of C language and assembly language in stm32

Catalog

One .Keil Next C Language call assembler

Two . Original assembly language Init_1 Change the type of the function to int Init_1(init) , This function function is modified to Pass in an integer number x, The function returns an integer number after running x+100.

3、 ... and . Calling one in assembly function C Functions written in language

Four . summary

---

One .Keil Next C Language call assembler

Create a new file under the project main.c and Function.s

 main.c

# include<stdio.h>

extern void	Init_1(void);

int main(){
	
	Init_1();
	
	return 0;
}

Function.s

	AREA	MY_FUNCTION,CODE,READONLY
	EXPORT 	Init_1  




Init_1

	MOV R1,#0     
	MOV R2,#0	  
	
LOOP	
	CMP R1,#10	  
	BHS LOOP_END  	  
	ADD R2,#1	  
	ADD R1,#1     
	B LOOP		  
	
LOOP_END
	NOP	
	
	END  

Compile debugging ：

Two . Original assembly language Init_1 Change the type of the function to int Init_1(init) , This function function is modified to Pass in an integer number x, The function returns an integer number after running x+100.

modify main.c The contents of the document

main.c

# include<stdio.h>
 
extern int Init_1(int x);
 
int main(){
	
	int xx = Init_1(10);
	printf("%d", xx);
	
	return 0;
}

Function.s

 
	AREA	MY_Function,CODE,READONLY
	EXPORT 	Init_1 
 
 
 
 
Init_1
	ADD R0,#100    
	MOV PC,LR		
	
	
LOOP	
	CMP R1,#10	  
	BHS LOOP_END  	  
	ADD R2,#1	  
	ADD R1,#1     
	B LOOP		  
	
LOOP_END
	NOP	
	
	
	END  

result

 

3、 ... and . Calling one in assembly function C Functions written in language

main.c

# include<stdio.h>
 
extern void	Init_1(void);
 
int get5(void);
 
int main(){
	
	printf("Begin...\n");
	Init_1();
 
	
	return 0;
}
 
int get5(){
	return 5;
}
 

Function.s

 
	AREA	MY_Function,CODE,READONLY
	EXPORT 	Init_1  
	IMPORT  get5    
 
 
 
 
Init_1
 
	MOV R1,#0     
	MOV R2,#0	  
	
LOOP	
	CMP R1,#10	  
	BHS LOOP_END  	  
	ADD R2,#1	 
	ADD R1,#1    
	BL get5  	 
	B LOOP		 
	
LOOP_END
	NOP	
	
	
	END 

result

Four . summary

Through this experiment , I am right. C The transfer method of language call function parameters and ARM Better understanding of register usage .

reference ：(3 Bar message ) STM32 Next C Mixed programming of VB and assembly language _Baker The blog of -CSDN Blog