Trying to fix svim when up key ispressed

bootloader.nasm

@@ -31,7 +31,7 @@ start:
 	mov si, enter_debug_mode
     call print 
     call printCRLF
-    %IF 1
+    %IF 0
     ; here goes wait call, for the user to enter debug mode. 
     ; Wating for 2 seconds: 
     mov ah, 0x86   ; code for waiting interupt call

lib/svim.nasm

@@ -12,6 +12,7 @@ svim:
     mov BYTE [bx], 0 ; be sure that the first byte is zero. 
     mov WORD [svim_counter_char_in_left_buffer], 0 ; reset these to zero
     mov WORD [svim_counter_char_in_right_buffer], 0 
+    mov WORD [svim_get_cursor_distance_to_next_line_break], 0
 
     call os_clear_screen
     
@@ -114,6 +115,7 @@ svim:
     ;add bx, svim_magic_buffer_size - 2
     ;mov ax, [bx]
     mov [svim_counter_char_in_left_buffer], ax
+
     ;mov [svim_counter_char_in_left_buffer], ax
     ; print buffer
     ;mov si, [buffer_for_svim_base_left_of_cursor]
@@ -178,7 +180,7 @@ svim:
 .check_up_key:
     cmp ax, 0x48e0 ; up key
     jne .check_right_key
-
+    call handle_up_key_pressed
     jmp .svim_loop    
 .check_right_key:
     cmp ax, 0x4de0 ; right key
@@ -275,7 +277,10 @@ svim:
 
 
 handle_left_key_pressed:
+    pusha
     mov ax, [svim_counter_char_in_left_buffer]
+    cmp ax, 0
+    je .end
     mov bx, [buffer_for_svim_base_left_of_cursor]
     add bx, ax
     dec bx ; Because it faces the next free spot
@@ -299,10 +304,11 @@ handle_left_key_pressed:
     jne .end
     call handle_left_key_pressed ; we have hit a linebreak and need to go once more
 .end:    
+    popa
     ret
 
 handle_right_key_pressed:
-
+    pusha
     mov ax, [svim_counter_char_in_right_buffer]
     cmp ax, 0 ; check if we have more on the right side of the buffer
     je .end    ; If we don't, jump to the end and do nothing. 
@@ -329,8 +335,41 @@ handle_right_key_pressed:
     jne .end 
     call handle_right_key_pressed ; we have hit a linebreak and need to go once more
 .end:    
+    popa
     ret
 
+handle_up_key_pressed:
+    call get_cursor_position  ; Find the position of the cursor
+    xor cx, cx
+    mov cl, dl                ; Store coulun count
+    inc cx
+    push cx                   ; save the column count. 
+.find_first_line_break:
+    cmp BYTE cl, 0
+    je .find_right_position_on_new_line
+    call handle_left_key_pressed
+    dec cl
+    jmp .find_first_line_break
+.find_right_position_on_new_line:
+    call svim_get_left_line_count ; updates the value in svim_get_cursor_distance_to_next_line_break
+    mov ax, [svim_get_cursor_distance_to_next_line_break]    
+    call dumpax
+    pop cx
+.move_curser_to_correct_position_on_the_new_line:
+    cmp cx, ax
+    jge .end
+    call handle_left_key_pressed
+    dec ax
+    jmp .move_curser_to_correct_position_on_the_new_line
+.end:
+    ret
+
+
+handle_down_key_pressed:
+
+    ret
+
+
 get_cursor_position:
     xor ax, ax
     xor bx, bx
@@ -339,24 +378,27 @@ get_cursor_position:
     int 0x10
     ret
 
-svim_get_end_of_line_count: 
+svim_get_left_line_count: 
     pusha
     xor ax, ax ; Number of chars in the right side buffer
     xor cx, cx ; This is our counter to the next line break
-    mov ax, [svim_counter_char_in_right_buffer]
-    mov bx, buffer_for_svim_base_right_of_cursor
-.check_next:    
-    cmp ax, 0 ; No more chars to check, we have hit the end of the last line
+    mov ax, [svim_counter_char_in_left_buffer]
+    mov bx, buffer_for_svim_base_left_of_cursor
+    add bx, ax
+.check_next:
+    cmp ax, 0 ; check if we have hit the absolut beginnig of the string
     je .end
-    cmp BYTE [bx], 13 ; See if we have hit an linebreak
-    je .end_procedure 
-    sub ax, 1 ; substract one for the numbers of element that we are looking at
-    inc bx ; add one the our buffer to look at the next element     
-    inc cx
-.end_procedure:
-    mov [svim_get_cursor_distance_to_next_line_break], cx
-
+    mov BYTE dl, [bx]
+    cmp BYTE dl, 13 ; See if we have hit an linebreak
+    je .end_line_break 
+    dec bx ; dec one, to check the prev char, until we hit a line break. 
+    dec ax  
+    inc cx ; add one to the counter
+    jmp .check_next
+.end_line_break: 
+    inc cx ; add one to the counter    
 .end:
+    mov WORD [svim_get_cursor_distance_to_next_line_break], cx
     popa
     ret
 
@@ -407,7 +449,7 @@ svim_counter_char_in_left_buffer dw 0
 svim_counter_char_in_right_buffer dw 0
 seperate_line  db '________________________________________________________________________________', 0
 welcome_svim db 'Vim like text editor for SingOS, ESC to exit', 0
-welcome_svim_select_file db 'svim v0.0.27 - Open file: ', 0
+welcome_svim_select_file db 'svim v0.0.28 - Open file: ', 0
 welcome_svim_enter_fileindex db 'Enter fileindex: ', 0
 fileindex_for_open_file dw 0
 svim_total_file_size_counter dw 0