i was trying to understand how the strings work and i was looking at tinypad code, when it calls fasm with parameters... in the
start_fasm:

mov esi,filename
mov edi,fasm_parameters

cmp byte [esi],'/'
je .yes_systree

mov ecx,[filename_len]
rep movsb
mov al,',' ;this adds the comma after the filename in the fasm_parameters(example (filename=test.asm):fasm_parameter='test.asm,'... maybe i'm wrong ? :S
stosb

mov ecx,[filename_len];it starts all again, but why?
add ecx,-4 ;and what is this code doing?
mov esi,filename
rep movsb;this copies the filename again to fasm_parameters?
;then fasm_parameters=¿¿¿???

mov al,',';it adds the comma again
stosb
;i don't understand the next code
mov [edi],dword '/RD/'
add edi,4
mov [edi],word '1/'
inc edi
inc edi

mov al,0; and this adds the 0 at the end of the string
stosb


ok, as you can see, i'm very newbie, but i hope you can help me, i really want to understand this code (i'm also playing a little with this program in particular)

i understood almost everything, thanx!, anyway the last part is not too clear to me, i thought that if you did this:mov [edi],dword '/RD/'
you would be deleting the old data in edi, but i guess that i was wrong
and why this adds the '1/' whitout worring about the variable size (i have a lot of confusing things in my mind)...
ok, to tell the truth i need an explanation of the last things... after the
" ;i don't understand the next code "
mov [edi],word '1/'
inc edi
inc edi

OK.
Sorry my english
it puts string '1/' to the some place in memory, by address stored in edi.


There is no variables in Assembler. There are Sirs Registers and Mrs memory.
you see word 'word' next to '1/'? It orders precisely to store 2 bytes in RAM.