Narue

After division, DX contains the remainder. In this case, DX holds the digit we just sliced off. Earlier I posted how the division works:
The only problem is that these values are bare. 3 is 3, 2 is 2, and 1 is 1. You want the ASCII representation of those numbers, where 3 is 51, 2 is 50, and 1 is 49. So to force that representation, you take the bare number and add '0', which has a value of 48.

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Even if the voices aren't real, they have some pretty good ideas.

kruptof

nicely explain Narue u have taught me alot in this thread alone and i can't think of anyway to thank you.................THANK YOU

kruptof

hey Narue was just playing around with the code and when i change it to something like this: you don't get an ouput...... is like as if the save variable is blank?....................why is this.

Narue

jnz relies on test to set the flags properly for the loop. dec also modifies flags, so if you move dec after test, jnz uses the result of dec as the loop condition. The reason it doesn't print anything is because save is initialized to DOS string terminators (the '$' character). When DI is 1, it's decremented to 0 and jnz is false, so the loop ends before filling in the first character of save. Since the first character is still '$', it's technically an empty string.

__________________
Even if the voices aren't real, they have some pretty good ideas.

kruptof

oh ok...............that makes sense.............nicely explained again............your pretty advanced at this langauge do you do as a career Narue?

kruptof

try playing around with this code even more but this time the DOS window just freezes when ever i run this program, here is the code:

Narue

>jmp calc
There's no need for this unless you're jumping over something. Since calc is the next thing in the source, execution will fall through to it without your help.

>jnz calc
jne would make your intentions more obvious.

>add save,10
This doesn't make sense.

>mov al,00
You forgot the int 21h to terminate your program.

One big issue is the infinite loop you're going to cause by entering strings longer than two characters. Since you test the loop condition at the bottom, after you copy to save, entering something like 123 will actually cause '1', '2', 3', 10 to be written to memory. That erases the last '$', and 09h will just keep going until it finds a '$' somewhere else in memory. So you need to use a top testing loop to avoid writing the carriage return to save:
An alternative since a top testing loop uses an extra jump instruction, one at the top and one at the bottom, you can move that extra jump outside of the loop by using a bottom testing loop with a condition part:
That's slightly more efficient, but it's also harder to follow.

>do you do as a career Narue?
I'm a professional programmer, yes. I tend to use assembly more than many programmers, but most of my work is in C and C++.

__________________
Even if the voices aren't real, they have some pretty good ideas.

kruptof

okay i see my mistake................but what if i wanted to add a number to whats inside the save variable that's what the "add save,10" was for

Narue

>but what if i wanted to add a number to whats inside the save variable
You access the memory just like you did when you copied the character in the first place:

__________________
Even if the voices aren't real, they have some pretty good ideas.

kruptof

i Hav tried to run the following code:
but i keep an dialog boxes with an error on it (i have attached the image of this) do you know what this means Narue and if so can you please explain it to me

Attached Images

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