Streamline the commands and give the major parts of the code headings

src/boot.asm

@@ -8,16 +8,16 @@ mov ax, 0x1000
 mov es, ax
 mov bx, 0
 
-mov al, 32
+mov al, 0x20
 mov dh, 0
 mov ch, 0
-mov cl, 2
+mov cl, 0x2
 
-mov ah, 2
+mov ah, 0x2
 int 0x13
 
 jmp 0x1000:0
 
-times 510-($-$$) db 0
+times 0x1fe-($-$$) db 0
 db 0x55
 db 0xaa

src/os.asm

@@ -1,3 +1,5 @@
+;Main
+
 mov ax, 0x1000
 mov ds, ax
 
@@ -7,19 +9,31 @@ call print
 loop:
 mov si, prompt
 call print
-mov di, input
 call read
 cmp byte [input], 0
 je loop
+
+execute:
+.hello:
 mov si, input
-call print
-mov si, newline
-call print
-mov cx, 0x4e
-mov di, input
-mov al, 0
-rep stosb
+mov di, command.hello
+call compare
+jnc .echo
+call hello
 jmp loop
+.echo:
+mov si, input
+mov di, command.echo
+call compare
+jnc .unknown
+call echo
+jmp loop
+.unknown:
+mov si, command.unknown
+call print
+jmp loop
+
+;Calls
 
 print:
 lodsb
@@ -32,15 +46,20 @@ jmp print
 ret
 
 read:
+mov di, input
+mov cx, 0x80
+mov al, 0
+rep stosb
+mov di, input
 mov cl, 0
 .loop:
 mov ah, 0
 int 0x16
 cmp al, 0xd
 je .return
-cmp al, 8
+cmp al, 0x8
 je .backspace
-cmp cl, 0x4d
+cmp cl, 0x80
 je .loop
 cmp al, 0x20
 je .space
@@ -76,18 +95,78 @@ dec di
 dec cl
 jmp .loop
 .return:
+mov di, input.end
+.tspfind:
+dec di
+cmp byte [di], 0
+je .tspfind
+cmp byte [di], 0x20
+je .tsperase
+jmp .done
+.tsperase:
+mov al, 0
+stosb
+dec di
+jmp .tspfind
+.done:
 mov si, newline
 call print
 ret
 
+compare:
+mov al, [si]
+mov bl, [di]
+cmp al, bl
+jne .nequal
+cmp al, 0
+je .equal
+inc si
+inc di
+jmp compare
+.nequal:
+clc
+ret
+.equal:
+stc
+ret
+
+hello:
+mov si, .msg
+call print
+ret
+.msg:
+db "Hello world!", 0xd, 0xa, 0
+
+echo:
+call read
+cmp byte [input], 0
+je loop
+mov si, input
+call print
+mov si, newline
+call print
+ret
+
+;Data
+
 welcome:
 db 0xd, 0xa, "Welcome to EttinOS!", 0xd, 0xa, 0xd, 0xa, 0
 
-input:
-times 78 db 0
-
 prompt:
 db "> ", 0
 
+command:
+.hello:
+db "hello", 0
+.echo:
+db "echo", 0
+.unknown:
+db "Unknown command", 0xd, 0xa, 0
+
 newline:
 db 0xd, 0xa, 0
+
+input:
+times 0x80 db 0
+.end:
+db 0