微算機lab5

tags: microcontroller lab

題目
連結可能失效！！！

main.c

#include <xc.h>

extern unsigned int devide(unsigned int a, unsigned int b);

void main(void){
    

    volatile unsigned int res = devide(255, 2);
    volatile unsigned char quotient =  (unsigned char) (res>>8);
    volatile unsigned char remainder = (unsigned char) (res);
    while(1);
    return;
}

---

devide.asm

#include "xc.inc"

GLOBAL _devide
    
PSECT mytext, local, class=CODE, reloc=2
 
 init:
    subff macro va,vb
	movff vb, WREG
	subwf va, W
    endm
    
_devide:
    movlw 0xFF
    movwf 0x09, F
    movff 0x01, LATA
    movff 0x03, LATB
moved:
    incf 0x0A
    rlcf LATB
    bnc moved
    rrcf LATB
start:
    subff LATA, LATB
    btfss WREG,7
    rcall addcarry
    rlcf LATC
    rcall clearcarry
    rrcf LATB
    decf 0x0A
    bz finish
    goto start
addcarry:
    movwf LATA
    rcall setcarry
    return
setcarry:
    movlw 0xFF
    movwf 0x09
    rlcf 0x09
    return
clearcarry:
    movlw 0x00
    movwf 0x09
    rlcf 0x09
    return
finish:
    movff LATC, 0x02
    movff LATA, 0x01
    movff LATC, 0x03
    movff LATA, 0x04
	return