PIC Assembly For Loop Example

Sun May 12, 2013 12:10 am

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Code:: #include <p18F8720.inc> radix dec n equ D'50' sum_hi set 0x01 ; high byte of sum sum_lo set 0x00 ; low byte of sum i set 0x02 ; loop index i org 0x00 ; reset vector goto start org 0x08 retfie org 0x18 retfie start clrf sum_hi,A ; initialize sum to 0 clrf sum_lo,A ; clrf i,A ; initialize i to 0 incf i,F,A ; i starts from 1 sum_lp movlw n ; place n in WREG cpfsgt i,A ; compare i with n and skip if i > n bra add_lp ; perform addition when i less or equal 50 bra exit_sum ; it is done when i > 50 add_lp movf i,W,A ; place i in WREG addwf sum_lo,F,A ; add i to sum_lo movlw 0 addwfc sum_hi,F,A ; add carry to sum_hi incf i,F,A ; increment loop index i by 1 bra sum_lp exit_sum nop bra exit_sum end