I am totally lost when it comes to assembly language. My teacher just decided one day at the end of this semester to give us a programming assignment in assembly language and has barely taught us anything. I have to use five subroutines: main, add, subtract, multiply, divide and cannot use any global variables (no .BLOCK variables). main should read in the two values and pass them as parameters to the other 4 subroutines. My addition and subtraction work fine, but multiplication and division i have no idea on. I am still pretty confused on stacks and haven't been able to find much info on them in this format of assembly language. Any help would be appreciated.
BR main ;ADD METHOD param1: .EQUATE 6 param2: .EQUATE 4 sum1: .EQUATE 0 add: SUBSP 2,i LDA param1,s ADDA param2,s STA sum1,s DECO sum1,s CHARO '\n',i RET2 ;SUBTRACT METHOD param3: .EQUATE 6 param4: .EQUATE 4 sum2: .EQUATE 0 subtract: SUBSP 2,i LDA param3,s SUBA param4,s STA sum2,s DECO sum2,s CHARO '\n',i RET2 ;MULTIPLY METHOD param5: .EQUATE 6 param6: .EQUATE 4 sum3: .EQUATE 0 multiply: SUBSP 2,i LDA param5,s ASLA ;no idea if this is what is supposed to be used to multiply or not STA sum3,s DECO sum3,s CHARO '\n',i RET2 ;DIVIDE METHOD ;need to find quotient AND remainder param7: .EQUATE 6 param8: .EQUATE 4 ;MAIN METHOD num1: .EQUATE 2 num2: .EQUATE 0 main:SUBSP 2,i STRO msg1,d DECI num1,s STRO msg2,d DECI num2,s DECO num1,s CHARO ' ',i CHARO '+',i CHARO ' ',i DECO num2,s CHARO ' ',i CHARO '=',i CHARO ' ',i CALL add DECO num1,s CHARO ' ',i CHARO '-',i CHARO ' ',i DECO num2,s CHARO ' ',i CHARO '=',i CHARO ' ',i CALL subtract DECO num1,s CHARO ' ',i CHARO '*',i CHARO ' ',i DECO num2,s CHARO ' ',i CHARO '=',i CHARO ' ',i CALL multiply ADDSP 2,i STOP msg1:.ASCII "Please enter the first positive value (0 to quit): \x00" msg2:.ASCII "Please enter the second positive value (0 to quit): \x00" .END