[desijoker]

hey guys .i am trying to write a lc3 assembly language program that takes two input numbers and prints out "x * y = z".

i can get it to work for numbers 0-9 however any numbers above that i get weird letters or symbols.
Also how i can i make it so that it can not only take only 1 inputs per GETC but two numbers eg. "10 * 12= 120"?
Any help would be appreaciated!

Here's what i have done so far

    .ORIG x3000
    AND R3, R3, #0 ;r3 stores the sum, set r3 to zero
    AND R4, R4, #0 ;r4 is the counter
    LD R5, INVERSE_ASCII_OFFSET ;inverse ascii offset
    LD R6, DECIMAL_OFFSET ;decimal offset
    ;---------------------
    ;storing first input digits
    LEA R0, display1 ;load the address of the 'display1' message string
    PUTS ;Prints the message string
    GETC ;get the first number
    OUT ;print the first number
    ADD R1, R0, #0 ;store input value(ascii) to r1
    ADD R1, R1, R5 ;get real value of r1
    ;storing second input digits
    LEA R0, display2 ;load the address of the 'display2' message string
    PUTS ;Prints the message string
    GETC ;get the first number
    OUT ;print the first number
    ADD R2, R0, #0 ;store input value(ascii) to r2
    ADD R2, R2, R5 ;get real value of r2
    ;----------------------
    ADD R4, R2, #0 ;fill counter with multiplier
    MULTIPLICATION:
    ADD R3, R3, R1 ;add to sum
    ADD R4, R4, #-1 ;decrease counter by one
    BRp MULTIPLICATION ;continue loop until multiplier is 0
    LEA R0, stringResult
    PUTS
    ADD R0, R3, R6 ;move result to r0
    OUT ;print result
    HALT
    display1 .STRINGZ "\nenter the 1st no.: "
    display2 .STRINGZ "\nenter the 2nd no.: "
    stringResult .STRINGZ "\nResult: "
    INVERSE_ASCII_OFFSET .fill xFFD0 ; Negative of x0030.
    DECIMAL_OFFSET .fill #48
    .END

[turboscrew]

GETC reads just one character, not a number. You need to read in the digits one by one.

Quote

Also how i can i make it so that it can not only take only 1 inputs per GETC but two numbers

You can't.
You just read the stuff in a loop.

[desijoker]

turboscrew, on 09 May 2012 - 10:24 PM, said:

GETC reads just one character, not a number. You need to read in the digits one by one.

Quote

Also how i can i make it so that it can not only take only 1 inputs per GETC but two numbers

You can't.
You just read the stuff in a loop.

how would i read a digit 1 by one? wouldn't it be easier if i multiply the input by 10?

[turboscrew]

What I mean: You give "123"
first GETC returns "1"
second GETC returns "2"
3rd GETC returns "3"

That's what I ment by "digit by digit".
Actually it's a good way to read them as:

number = 0
digit = GETC()
WHILE (digit IN ['0' .. '9'] DO
  digit =  digit - '0'
  number = number * 10 + digit
  digit = GETC()
ENDWHILE