2 ;; -----------------------------------------------------------------------
4 ;; Copyright 1994-2002 H. Peter Anvin - All Rights Reserved
6 ;; This program is free software; you can redistribute it and/or modify
7 ;; it under the terms of the GNU General Public License as published by
8 ;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
9 ;; Bostom MA 02111-1307, USA; either version 2 of the License, or
10 ;; (at your option) any later version; incorporated herein by reference.
12 ;; -----------------------------------------------------------------------
15 ; This file should be entered with the config file open (for getc)
17 call parse_config ; Parse configuration file
20 ; Check whether or not we are supposed to display the boot prompt.
23 cmp word [ForcePrompt],byte 0 ; Force prompt?
25 test byte [KbdFlags],5Bh ; Caps, Scroll, Shift, Alt
26 jz auto_boot ; If neither, default boot
32 mov byte [FuncFlag],0 ; <Ctrl-F> not pressed
35 ; get the very first character -- we can either time
36 ; out, or receive a character press at this time. Some dorky BIOSes stuff
37 ; a return in the buffer on bootup, so wipe the keyboard buffer first.
39 clear_buffer: mov ah,1 ; Check for pending char
44 jmp short clear_buffer
49 jz get_char ; Timeout == 0 -> no timeout
50 inc cx ; The first loop will happen
51 ; immediately as we don't
52 ; know the appropriate DX value
57 mov dx,[BIOS_timer] ; Get time "of day"
59 cmp dx,ax ; Has the timer advanced?
62 loop time_loop ; If so, decrement counter
66 mov si,TimeOutCmd ; Copy timeoutcommand if we have one...
67 mov cx,[TimeOutCmdLen]
72 get_char_pop: pop eax ; Clear stack
80 got_ascii: cmp al,7Fh ; <DEL> == <BS>
85 cmp di,command_line ; Space must not be first
87 enter_char: test byte [FuncFlag],1
95 .not_ctrl_f: cmp di,max_cmd_len+command_line ; Check there's space
98 call writechr ; Echo to screen
100 not_ascii: mov byte [FuncFlag],0
103 cmp al,06h ; <Ctrl-F>
105 cmp al,16h ; <Ctrl-V>
107 cmp al,08h ; Backspace
109 backspace: cmp di,command_line ; Make sure there is anything
110 je get_char ; to erase
111 dec di ; Unstore one character
112 mov si,wipe_char ; and erase it from the screen
117 mov byte [FuncFlag],1
121 ctrl_f_0: add al,10 ; <Ctrl-F>0 == F10
127 ; AL = 0 if we get here
133 show_help: ; AX = func key # (0 = F1, 9 = F10)
134 push di ; Save end-of-cmdline pointer
135 shl ax,FILENAME_MAX_LG2 ; Convert to pointer
138 cmp byte [di],NULLFILE
139 je short fk_nofile ; Undefined F-key
141 jz short fk_nofile ; File not found
149 push di ; Command line write pointer
150 mov si,syslinux_banner
155 ; ... fall through ...
157 ; Write the boot prompt and command line again and
158 ; wait for input. Note that this expects the cursor
159 ; to already have been CRLF'd, and that the old value
160 ; of DI (the command line write pointer) is on the stack.
164 pop di ; Command line write pointer
166 mov byte [di],0 ; Null-terminate command line
168 call cwritestr ; Write command line so far
174 mov cx,(max_cmd_len+4) >> 2
176 jmp short load_kernel
179 cmp di,command_line ; Did we just hit return?
181 xor al,al ; Store a final null
184 load_kernel: ; Load the kernel now
186 ; First we need to mangle the kernel name the way DOS would...
196 ; Fast-forward to first option (we start over from the beginning, since
197 ; mangle_name doesn't necessarily return a consistent ending state.)
202 clin_is_wsp: and al,al
207 clin_opt_ptr: dec si ; Point to first nonblank
208 mov [CmdOptPtr],si ; Save ptr to first option
210 ; Now check if it is a "virtual kernel"
218 xor si,si ; Point to first vkernel
221 repe cmpsb ; Is this it?
228 ; Not a "virtual kernel" - check that's OK and construct the command line
230 cmp word [AllowImplicit],byte 0
246 ; Find the kernel on disk
248 get_kernel: mov byte [KernelName+FILENAME_MAX],0 ; Zero-terminate filename/extension
249 %if IS_SYSLINUX || IS_MDSLINUX ; SYSLINUX has to deal with DOS mangled names...
250 mov eax,[KernelName+8] ; Save initial extension
251 mov [exten_table_end],eax ; Last case == initial ext.
255 mov cx,FILENAME_MAX-5 ; Need 4 chars + null
256 repne scasb ; Scan for final null
258 dec di ; Point to final null
259 .no_skip: mov [KernelExtPtr],di
262 .search_loop: push bx
263 mov di,KernelName ; Search on disk
267 mov eax,[bx] ; Try a different extension
268 %if IS_SYSLINUX || IS_MDSLINUX
269 mov [KernelName+8],eax
271 mov si,[KernelExtPtr]
276 cmp bx,exten_table_end
277 jna .search_loop ; allow == case (final case)
282 call unmangle_name ; Get human form
283 mov si,err_notfound ; Complain about missing kernel
288 jmp abort_load ; Ask user for clue
290 ; bad_implicit: The user entered a nonvirtual kernel name, with "implicit 0"
292 bad_implicit: mov si,KernelName ; For the error message
297 ; vk_found: We *are* using a "virtual kernel"
304 push es ; Restore old DS
307 push word real_mode_seg
310 mov si,VKernelBuf+vk_append
311 mov cx,[VKernelBuf+vk_appendlen]
313 mov [CmdLinePtr],di ; Where to add rest of cmd
315 pop di ; DI -> KernelName
317 mov si,VKernelBuf+vk_rname
318 mov cx,FILENAME_MAX ; We need ECX == CX later
322 mov al,[VKernelBuf+vk_ipappend]
325 xor bx,bx ; Try only one version
327 %if IS_SYSLINUX || IS_MDSLINUX
330 ; Is this a "localboot" pseudo-kernel?
331 cmp byte [VKernelBuf+vk_rname], 0
332 jne get_kernel ; No, it's real, go get it
334 mov ax, [VKernelBuf+vk_rname+1]
339 ; kernel_corrupt: Called if the kernel file does not seem healthy
341 kernel_corrupt: mov si,err_notkernel
344 ; This is it! We have a name (and location on the disk)... let's load
345 ; that sucker!! First we have to decide what kind of file this is; base
346 ; that decision on the file extension. The following extensions are
347 ; recognized; case insensitive:
349 ; .com - COMBOOT image
350 ; .cbt - COMBOOT image
353 ; .0 - PXE bootstrap program (PXELINUX only)
355 ; .bss - Boot sector, but transfer over DOS superblock (SYSLINUX only)
356 ; .img - Floppy image (ISOLINUX only)
358 ; Anything else is assumed to be a Linux kernel.
366 mov [KernelCNameLen],di
369 %if IS_SYSLINUX || IS_MDSLINUX
370 mov ecx,[KernelName+7]
381 .one_step: mov ecx,[di-4] ; 4 bytes before end
387 ; At this point, DX:AX contains the size of the kernel, and SI contains
388 ; the file handle/cluster pointer.
390 or ecx,20202000h ; Force lower case
406 %if IS_SYSLINUX || IS_MDSLINUX
419 ; Otherwise Linux kernel