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June 7th, 2009, 07:16 AM
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| |  Anyone know assembler?
Is there anyone here who knows MASM assembly language? If so, would anyone be willing to take a look at a simple program that I started to comment? See I want to make sure that I am understand what is going on in the program. The best way to do that is by commenting the program. If anyone is willing to see if I am on the write track, please reply and I will post the code. |
June 7th, 2009, 11:07 AM
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Quote:
Originally Posted by gammaman  Is there anyone here who knows MASM assembly language? If so, would anyone be willing to take a look at a simple program that I started to comment? See I want to make sure that I am understand what is going on in the program. The best way to do that is by commenting the program. If anyone is willing to see if I am on the write track, please reply and I will post the code. | I'd like to take a look. I've written several programs (a CriticalPath/Pert program; a chess program; and dozens of other little buggers) using MicroSoft Assembler, and a bunch of one shot snippets. If the code is short (about 5 printed pages) I do not see a problem listing it here. However, if it is longer than that it would be best to post it elsewhere and provide a link to it. My opinion. Check with the mods for non-math posts. |
June 7th, 2009, 11:53 AM
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Yes it is very short. Again I just really want some help commenting the code and some input on what I have already commented. Code: title prog3
;this program eliminates a number from a list specifically, 50
.model small
.stack 100h ;256 byte stack
.data
array db 10, 20, 30, 40, 50, 60, 70, 80, 90
arraysize dw 9
.code
main proc
extrn writeint:proc, crlf:proc ;Writeint.obj found in fierro.lib,Crlf.obj found in fierro.lib
mov ax, @data ;copy the address of the data segment
mov ds, ax ;@data into ds register
mov bx, offset array ;get the address of array into bx
mov cx, arraysize ;put arraysize into cx register
mov ax, 4
call delete
call printout
mov ax, 4c00h
int 21h
main endp
delete proc
add bx, ax ;add value in ax to value in bx
sub cx, ax ;subtract ax from value in cx
dec cx
repeat:
mov ax, [bx+1]
mov [bx], ax
inc bx
loop repeat
ret
delete endp
printout proc
mov si,0
mov cx, arraysize
dec cx ;decrement the cx register
again:
mov ah,0
mov al, [array + si]
mov bx, 10
call writeint ; in base 10 format
mov dl, " "
mov ah, 2 ;dispay character function
int 21h
inc si ;use si to count how many times we push onto the stack
loop again
ret
printout endp
end main
 |
June 9th, 2009, 06:05 AM
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Quote:
Originally Posted by gammaman Yes it is very short. Again I just really want some help commenting the code and some input on what I have already commented. Code: title prog3
;this program eliminates a number from a list specifically, 50
.model small
.stack 100h ;256 byte stack
.data
array db 10, 20, 30, 40, 50, 60, 70, 80, 90
arraysize dw 9
.code
main proc
extrn writeint:proc, crlf:proc ;Writeint.obj found in fierro.lib,Crlf.obj found in fierro.lib
mov ax, @data ;copy the address of the data segment
mov ds, ax ;@data into ds register
mov bx, offset array ;get the address of array into bx
mov cx, arraysize ;put arraysize into cx register
mov ax, 4
call delete
call printout
mov ax, 4c00h
int 21h
main endp
delete proc
add bx, ax ;add value in ax to value in bx
sub cx, ax ;subtract ax from value in cx
dec cx
;move up the remaining items
repeat:
mov ax, [bx+1]
mov [bx], ax
inc bx
loop repeat
ret
delete endp
printout proc
mov si,0
mov cx, arraysize
dec cx ;decrement the cx register
again:
mov ah,0
mov al, [array + si]
mov bx, 10
call writeint ; in base 10 format
mov dl, " "
mov ah, 2 ;dispay character function
int 21h
inc si ;use si to count how many times we push onto the stack
loop again
ret
printout endp
end main
| The items highlighted in blue are meaningful. They tell me something that at first glance explains what's up.
"in base 10 format" is beautiful.
normally it is hex, but this clarifies intent!
The highlighted red information, merely states exactly what the instruction is doing. There is nothing "wrong" with that, but it does not help.
In a few months when you look at something like Code:
delete proc
add bx, ax ;next value in data array
sub cx, ax ;items remaining
will give you an immediate idea of what is being done.
With your existing comment you will have to spend a few seconds to study the group of instructions before you come to the same conclusion.
You want to MINIMIZE your time when looking at code.
The lines highlighted in fuscia or pink [or whatever that color is] just makes a statement of what is occuring. When you review this (if ever you need to re-use code) the snippet becomes more like a paragraph and you can become more effective.
For me, one of the most helpful things, at the start of a procedure:
list the registers and identify what each contains;
state what is INTENDED to be done
and
which registers have valid data at exit.
Remember, there is no right or wrong way to comment your code.
[unless, of course, you are a member of a group that must alter/change each others pieces of code, that all are part of a larger product, then, naturally there is a RIGHT way of doing it.
As the boss says, "my way or you are deleted"]
The real value of the comments is that they will save you a lot of grief a few weeks/months/years down the way. | | Thread Tools | | | | Display Modes |  Linear Mode | 
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