乘除运算子程序.docVIP

工作过程中写了这些小程序，供大家参考。虽然在客户的应用中经过测试，但还是希望大家验证一下。如果有优化请告知。任何PIC单片机都适用。#define STATUS 3#define skpb skpnc ;skip if borrowed#define skpnb skpc ;skip if no borrow cblock 0x10PROD:2 ;2 bytes for productionQUOT:2 ;2 bytes for quotientPAVRA ;divider/multiplierPAVRB ;reminder / multiplierPAVRC ;additional byte spacemcount ;loop counter endc org 000h ;movlw 0x20; ;movwf PAVRA ;movlw 0x30 ;movwf PAVRB call BBYTE_DIV goto $-1;=;PROD:2 = PAVRA * PAVRB;=BYTE_MUL clrf PROD clrf PROD+1 movlw .8 movwf mcount_mul1 rlf PROD,f ;left shift 16-bit with LSB=0 bcf PROD,0 rlf PROD+1,f rlf PAVRA,w ;make left-rotate shift rlf PAVRA,f ;and check MSB skpc ;skip if MSB=1 goto _mul2 ;MSB=0 ;do when MSB=1 movf PAVRB,w addwf PROD,f skpnc incf PROD+1,f_mul2 decfsz mcount,f goto _mul1 retlw 0;=;WORD divided by BYTE =;PROD:2 / PAVRA = ;QUOT:2 = Quotient =;PAVRB = Reminder =;=WBYTE_DIV movf PAVRA,f skpnz retlw 1 ;return if divider=0 clrf PAVRB clrf PAVRC clrf QUOT clrf QUOT+1 movlw .16 movwf mcount_wdiv1 rlf QUOT,f ;adjust Quotient rlf QUOT+1,f bcf QUOT,0 ; rlf PROD+1,w rlf PROD,f rlf PROD+1,f ; rlf PAVRB,f rlf PAVRC,f ; movf PAVRA,w subwf PAVRB,f skpb ;skip if borrow goto _wdiv2 ;if borrow btfsc PAVRC,0 goto _wdiv2 addwf PAVRB,f bcf PAVRC,0 goto _wdiv3_wdiv2 ;if no borrow bcf PAVRC,0 bsf QUOT,0 _wdiv3 decfsz mcount,f goto _wdiv1 retlw 0;=;BYTE divided by BYTE =;PROD0 / PAVRA = ;QUOT0 = Quotient =;PAVRB = Reminder =;=BBYTE_DIV movf PAVRA,f skpnz retlw 1 ;return if divider=0 clrf PAVRB ;clear reminder clrf QUOT ;clear quotient movlw .8 movwf mcount ;for 8 times shift_bdiv1 rlf QUOT,f ;adjust Quotient bcf QUOT,0 ;left shift i bit ; rlf PROD,w ;get 1 bit, MSB first rlf PROD,f ;do rotate shift ; rlf PAVRB,f ;set to LSB of reminder ; movf PAVRA,w ;reminder - divider subwf PAVRB,f skpb ;skip if borrow goto _bdiv2 ;do if borrowed addwf PAVRB,f ;cancel subtraction goto _bdiv3 ;go for next_bdiv2 ;do if no borrow bsf QUOT,0 ;reminder div