You could, but why? If you use a text editor to write your programs you have to write the ascii symbols for each opcode. And thats a pain in the ****. Besides, you couldnt even write all the numbers you wanted, since some numbers cant be written with a keyboard.
AISB, i trying to make c compiler for amd64.
and, i am in some kind of dilemma,
sizeof(void *) is 8bytes, so some trick doesn't worked anymore.
anyway, i found that i have to use compiler to develop compiler. :-)
objdump -d is useful.
I don't see how could you execute anything with text editor.
You might be able to make executable "by hand", but for that you need acess to all 8 bit codes ( 0-255 ) whereas text editors have some limitations there, regardless of standard codetable they use (ISO-885x, ASCII, ISO-646/UTF-8 etc).
Why not use decent assembler, like NASM or FASM or even compiler, like gcc ?