Pic16f877双字节无符号乘法源程序
Pic16f877双字节无符号乘法源程序内容如下: listp=16f877A; list directive to define processor #include<p16f877A.inc> processor specific variable definitions;-设置寄存器-ACCALO EQU 0X20 ;存放乘数低8位ACCAHI EQU 0X21 ;存放乘数高8位ACCBLO EQU 0X22 ;存放被乘数低 8 位和乘积第 1623 位ACCBHI EQU 0X23 ;存放被乘数高 8 位和乘积第 2431 位ACCCLO EQU 0X24 ;存放乘积第 07 位ACCCHI EQU 0X25 ;存放乘积第 815 位MDD EQU 0X26 ;临时寄存器MEE EQU 0X27 ;临时寄存器TEMP EQU 0X28 ;临时寄存器Maros_A EQU 0x29;宏单字节被乘数Maros_B EQU 0x30;宏单字节乘数Result_A EQU 0x31;单字节乘法结果高8位Result_B EQU 0x32;单字节乘法结果低8位;- ORG 0x0000 ; 复位入口地址 nop ; 兼容ICD调试工具,必须加nop goto Main ; 跳转至Main函数;-使用宏实现单字节无符号整数的乘法-MUTIL_8 macro Maros_A,Maros_B movlw .8 movwf TEMP clrf Result_A clrf Result_BLOOP_1 bcf STATUS,C rrf Maros_B btfsc STATUS,C call Add_8 rrf Result_A rrf Result_B decfsz TEMP,f goto LOOP_1 endm ;结束宏指令 ;-Main movlw 0x15 ;送入乘数 movwf ACCALO movlw 0x40 movwf ACCAHI movlw 0x21 ;送入被乘数 movwf ACCBLO movlw 0x33 movwf ACCBHI call Mpy_32 ;调用子函数 nop movlw 0x11 movwf Maros_A movlw 0x2a movwf Maros_B MUTIL_8 Maros_A,Maros_B;调用宏指令 goto $;-Mpy_32 call Init ;调用初始化的子程序LOOP bcf STATUS,C rrf MEE ;MEE和MDD右移 rrf MDD btfsc STATUS,C call Add_16 rrf ACCBHI rrf ACCBLO rrf ACCCHI rrf ACCCLO decfsz TEMP goto LOOP RETURN;-Init movlw .16 ;初始化TEMP寄存器 movwf TEMP movf ACCBLO,W;被乘数送临时寄存器MEE和MDD movwf MDD movf ACCBHI,W movwf MEE clrf ACCBLO clrf ACCBHI clrf ACCCLO clrf ACCCHI RETURN;-16位二进制数相加-Add_16 movf ACCALO,W addwf ACCBLO,F btfsc STATUS,C incf ACCBHI,F movf ACCAHI,W addwf ACCBHI,F RETURN ;-8位二进制数加法子程序-Add_8 movf Maros_A,w addwf Result_A,f return;- END