CALLING ASSEMBLY DELAY ROUTINE FROM C SOURCE CODE

THIS POST IS ALL ABOUT HOW TO CALL AN ASSEMBLY ROUTINE FROM C SOURCE CODE

I PRESENT A EXAMPLE BELOW

THERE IS THREE FILES
1) DELAYS.ASM
2)DELAY_MAIN.C
3)DELAY_HEADER.H

DELAYS.ASM
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;;

;THIS IS A ASSEMBLY LANGUAGE ROUTINES WHICH GENERATING

; 1MILI SEC,500MILI SEC

;AND 1SEC ROUTINES.

;THIS ROUTINES CAN BE CALLED FROM C LANGUAGE USING BELOW FORMATS

;FOR 1 MILI SEC:: void delay_1_ms(void);

;FOR 500 MILI SEC:: void delay_500_ms(void);

;FOR 1 SEC:: void delay_1_sec(void);

;FILE NAME:DELAYS.ASM

;AUTHOR::RAJESH KUMAR SAHOO

;SKYPE ID:rajesh6115

;face book:www.facebook.com/rajesh6115

;                                  ;                                  ;





?PR?del_seg SEGMENT CODE

    PUBLIC delay_1_ms

    PUBLIC delay_500_ms

    PUBLIC delay_1_sec

    RSEG ?PR?del_seg

delay_1_ms:

    MOV R7,#250

    DJNZ R7,$

    MOV R7,#247

    DJNZ R7,$

    RET

delay_500_ms:

    MOV R6,#250

L1_500:

    ACALL delay_1_ms

    DJNZ R6,L1_500

    

    MOV R6,#248

L2_500:

    ACALL delay_1_ms

    DJNZ R6,L2_500

    MOV R6,#250

    DJNZ R6,$

    MOV R6,#247

    DJNZ R6,$

    NOP

    NOP

    RET

delay_1_sec:

    MOV R5,#8

LO_SEC:

    MOV R6,#124

LI_SEC:

    ACALL delay_1_ms

    DJNZ R6,LI_SEC

    DJNZ R5,LO_SEC

    MOV R5,#5

L_SEC:    

    ACALL delay_1_ms

    DJNZ R5,L_SEC

    MOV R5,#250

    DJNZ R5,$

    MOV R5,#237

    DJNZ R5,$

    RET

    END

  

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DELAY_MAIN.C
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/**
*THIS IS A C SOURCE CODE FROM WHERE ASSEMBLY ROUTINES ARE CALLED
*FILE NAME: DELAY_MAIN.C
*
*/

#include <reg51.h>
#include "delays_header.h"
void main()
{
    delay_1_sec();
    delay_500_ms();
    delay_1_ms();

    delay_1_sec();
}

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DELAY_HEADER.H
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#ifndef _delay_h_
#define _delay_h_

void delay_1_ms(void);
void delay_500_ms(void);
void delay_1_sec(void);

#endif

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THE HOLE EXAMPLE PROJECT YOU CAN DOWNLOAD FROM HERE
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