Command Line Optimization Level in NASM-CodePudding

I have written an assembly code to add ten numbers using byte variables, and code is error free.

Assembly code:

 ; a program to add ten numbers using byte variables
[org 0x0100]

jmp start 
num1: dw   10, 20, 30, 40, 50, 10, 20, 30, 40, 50
result: dw 0 

start: 
    ; initialize stuff 
    mov  ax, 0              ; reset the accumulator 
    mov  bx, 0              ; set the counter   
    outerloop: 
        add  ax, [num1   bx]
        add  bx, 2
        cmp bx, 20          ; sets ZF=1 when they are equal, 
                            ;un set ZF=0, if they are not equal  
        jne  outerloop 
    mov  [result], ax


    mov  ax, 0x4c00
    int  0x21

While assembling this code in NASM facing this error.

CodePudding user response：

NASM's command line options are case sensitive. It looks like you wanted to use the -o option (lower case o) to specify the output file name, so that -o C02-06.COM would write the output to a file named C02-06.COM. Instead you used upper-case -O, which requests optimization and (with your version) requires an additional flag, as the message says.

So change your command to -o C02-06.COM and it should work.