WebSVN – Kolibri OS – Diff – /kernel/trunk/boot/bootcode.inc

 ;;  KolibriOS 16-bit loader,                                    ;;
 ;;                        based on bootcode for MenuetOS        ;;
 ;;                                                              ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-$Revision: 3964 $
+$Revision: 3989 $
 getkey:                         ; Use BIOS INT 16h to read a key from the keyboard
 ; get number in range [bl,bh] (bl,bh in ['0'..'9'])
 ; in: bx=range
 ; out: ax=digit (1..9, 10 for 0)
-        mov     ah, 0           ; If 'int 16h' is called with 'ah' equal to zero, the BIOS will not return control
+        mov     ah, 0       ; If 'int 16h' is called with 'ah' equal to zero, the BIOS will not return control to the caller
-        int     16h             ; to the caller until a key is available in the system type ahead buffer. On return,
+        int     16h         ; until a key is available in the system type ahead buffer. On return, 'al' contains the ASCII
+        cmp     al, 27      ; code for the key read from the buffer and 'ah' contains the keyboard scan code. (27=>ESC)
-        cmp     al, bl          ; 'al' contains the ASCII code for the key read from the buffer and 'ah' contains
+        jz      @f          ; If ESC is pressed, return (user doesn't want to change any value).
-        jb      getkey          ; the keyboard scan code. Here we compare 'al' with the range of accepted characters.
+        cmp     al, bl      ; Compare 'al' (ASCII code of key pressed) with 'bl' (lowest accepted char from the range).
+        jb      getkey      ; ASCII code is below lowest accepted value => continue waiting for another key.
-        cmp     al, bh          ; If the key pressed is not in the range, continue waiting for another key.
+        cmp     al, bh      ; Compare 'al' (ASCII code of key pressed) with 'bh' (highest accepted char from the range).
-        ja      getkey
+        ja      getkey      ; ASCII code is above highest accepted value => continue waiting for another key.
-        push    ax              ; If the pressed key is in the accepted range, save it on the stack and echo to screen.
+        push    ax          ; If the pressed key is in the accepted range, save it on the stack and echo to screen.
         call    putchar
+        pop     ax
-        pop     ax
+        and     ax, 0Fh     ; Convert ASCII code to number: '1'->1, '2'->2, etc. 0Fh=1111b.
-        and     ax, 0Fh         ; ASCII code for '0' is 48 (110000b). 0F4=1111b. (110000b AND 1111b) = 0
+        jnz     @f          ; ASCII code for '0' is 48 (110000b). (110000b AND 1111b) = 0
-        jnz     @f              ; So if key '0' was entered, return 10 in 'ax'
-        mov     al, 10
+        mov     al, 10      ; So if key '0' was entered, return 10 in 'ax'
 @@:
         ret
+{
         mov     dx, row*256 + column
         call    setcursor
+}
+macro _ask_question question,range,variable_to_set
+{
+        _setcursor 16,0
+        mov     si, question    ; Print the question
+        call    print
+        mov     bx, range       ; range accepted for answer
+        call    getkey
+        cmp     al, 27          ; If ESC was pressed, do not change the value
+        jz      .esc_pressed
+        mov     [variable_to_set], al
+}
 boot_read_floppy:
         push    si
         xor     si, si
         mov     ah, 2   ; read
         cmp     al, 'd'         ; start launcher after kernel is loaded?
         jz      .change_d
         cmp     al, 'e'         ; select boot origin
         jnz     .show_remarks
 ; e) preboot_device = from where to boot?
-        _setcursor 16,0
-        mov     si, bdev
-        call    print
 if defined extended_primary_loader
-        mov     bx, '12'        ; range accepted for answer: 1-2
+        _ask_question bdev,'12',preboot_device              ; range accepted for answer: 1-2
 else
-        mov     bx, '14'        ; range accepted for answer: 1-4
+        _ask_question bdev,'14',preboot_device              ; range accepted for answer: 1-4
 end if
-        call    getkey
-        mov     [preboot_device], al
         _setcursor 14,0
 .d:
 if ~ defined extended_primary_loader
         mov     [.bSettingsChanged], 1
 end if
+.esc_pressed:
         call    clear_vmodes_table             ;clear vmodes_table
         jmp     .printcfg
 .change_a:
         call    clear_vmodes_table             ;clear vmodes_table
 .loops:
         call    draw_vmodes_table
         _setcursor 25,0         ; out of screen
         int     0x16
 ;        call    clear_table_cursor             ;clear current position of cursor
+        mov     si, word [cursor_pos]
+        cmp     al, 27              ; If ESC was pressed, do not change the value
-        mov     si, word [cursor_pos]
+        jz      .esc_pressed        ; Just exit the resolution selection box
         cmp     ah, 0x48;x,0x48E0               ; up
         jne     .down
         cmp     si, modes_table
         mov     word [preboot_graph], bp          ;save choose
         jmp     .d
 .change_b:                      ; b) preboot_biosdisk  = use BIOS disks through V86 emulation?
-        _setcursor 16,0
+;        _setcursor 16,0
 ;        mov     si, ask_dma    // (earlier was: preboot_dma  = use DMA access?)
 ;        call    print
 ;        mov     bx, '13'       ; range accepted for answer: 1-3
-;        call    getkey
-;        mov     [preboot_dma], al
-        mov     si, ask_bd
+;        call    getkey
-        call    print
-        mov     bx, '12'        ; range accepted for answer: 1-2
-        call    getkey
+;        mov     [preboot_dma], al
-        mov     [preboot_biosdisk], al
+        _ask_question ask_bd,'12',preboot_biosdisk              ; range accepted for answer: 1-2
         _setcursor 11,0
         jmp     .d
 ;.change_c:                     ; //  VRR is an obsolete functionality, used only with CRT monitors
 ;        call    getkey
 ;        mov     [preboot_vrrm], al
 ;        _setcursor 12,0
 ;        jmp     .d
 .change_c:                      ; c) preboot_debug = duplicates kernel debug output to the screen
-        _setcursor 16,0
-        mov     si, ask_debug
-        call    print
-        mov     bx, '12'        ; range accepted for answer: 1-2
+        _ask_question ask_debug,'12',preboot_debug              ; range accepted for answer: 1-2
-        call    getkey
-        mov     [preboot_debug], al
         _setcursor 12,0
         jmp     .d
 .change_d:                      ; d) preboot_launcher = start the first app (right now it's LAUNCHER) after kernel is loaded?
-        _setcursor 16,0
-        mov     si, ask_launcher
-        call    print
-        mov     bx, '12'        ; range accepted for answer: 1-2
+        _ask_question ask_launcher,'12',preboot_launcher        ; range accepted for answer: 1-2
-        call    getkey
-        mov     [preboot_launcher], al
         _setcursor 13,0
         jmp     .d
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 .say_on_off:
         pushf

Subversion Repositories Kolibri OS

(root)/kernel/trunk/boot/bootcode.inc – Rev 3964 → 3989