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
50 jz get_char ; Timeout == 0 -> no timeout
51 inc cx ; The first loop will happen
52 ; immediately as we don't
53 ; know the appropriate DX value
58 mov dx,[BIOS_timer] ; Get time "of day"
60 cmp dx,ax ; Has the timer advanced?
64 loop time_loop ; If so, decrement counter
68 mov si,Ontimeout ; Copy ontimeout command
69 mov cx,[OntimeoutLen] ; if we have one...
74 get_char_pop: pop eax ; Clear stack
82 got_ascii: cmp al,7Fh ; <DEL> == <BS>
87 cmp di,command_line ; Space must not be first
89 enter_char: test byte [FuncFlag],1
97 .not_ctrl_f: cmp di,max_cmd_len+command_line ; Check there's space
100 call writechr ; Echo to screen
102 not_ascii: mov byte [FuncFlag],0
105 cmp al,06h ; <Ctrl-F>
107 cmp al,16h ; <Ctrl-V>
109 cmp al,08h ; Backspace
111 backspace: cmp di,command_line ; Make sure there is anything
112 je get_char ; to erase
113 dec di ; Unstore one character
114 mov si,wipe_char ; and erase it from the screen
119 mov byte [FuncFlag],1
123 ctrl_f_0: add al,10 ; <Ctrl-F>0 == F10
129 ; AL = 0 if we get here
135 show_help: ; AX = func key # (0 = F1, 9 = F10)
136 push di ; Save end-of-cmdline pointer
137 shl ax,FILENAME_MAX_LG2 ; Convert to pointer
140 cmp byte [di],NULLFILE
141 je short fk_nofile ; Undefined F-key
143 jz short fk_nofile ; File not found
151 push di ; Command line write pointer
152 mov si,syslinux_banner
157 ; ... fall through ...
159 ; Write the boot prompt and command line again and
160 ; wait for input. Note that this expects the cursor
161 ; to already have been CRLF'd, and that the old value
162 ; of DI (the command line write pointer) is on the stack.
166 pop di ; Command line write pointer
168 mov byte [di],0 ; Null-terminate command line
170 call cwritestr ; Write command line so far
176 mov cx,(max_cmd_len+4) >> 2
178 jmp short load_kernel
181 cmp di,command_line ; Did we just hit return?
183 xor al,al ; Store a final null
186 load_kernel: ; Load the kernel now
188 ; First we need to mangle the kernel name the way DOS would...
198 ; Fast-forward to first option (we start over from the beginning, since
199 ; mangle_name doesn't necessarily return a consistent ending state.)
204 clin_is_wsp: and al,al
209 clin_opt_ptr: dec si ; Point to first nonblank
210 mov [CmdOptPtr],si ; Save ptr to first option
212 ; Now check if it is a "virtual kernel"
220 xor si,si ; Point to first vkernel
223 repe cmpsb ; Is this it?
230 ; Not a "virtual kernel" - check that's OK and construct the command line
232 cmp word [AllowImplicit],byte 0
248 ; Find the kernel on disk
250 get_kernel: mov byte [KernelName+FILENAME_MAX],0 ; Zero-terminate filename/extension
251 %if IS_SYSLINUX || IS_MDSLINUX ; SYSLINUX has to deal with DOS mangled names...
252 mov eax,[KernelName+8] ; Save initial extension
253 mov [exten_table_end],eax ; Last case == initial ext.
257 mov cx,FILENAME_MAX-5 ; Need 4 chars + null
258 repne scasb ; Scan for final null
260 dec di ; Point to final null
261 .no_skip: mov [KernelExtPtr],di
264 .search_loop: push bx
265 mov di,KernelName ; Search on disk
269 mov eax,[bx] ; Try a different extension
270 %if IS_SYSLINUX || IS_MDSLINUX
271 mov [KernelName+8],eax
273 mov si,[KernelExtPtr]
278 cmp bx,exten_table_end
279 jna .search_loop ; allow == case (final case)
280 ; Fall into bad_kernel
282 ; bad_kernel: Kernel image not found
283 ; bad_implicit: The user entered a nonvirtual kernel name, with "implicit 0"
294 call unmangle_name ; Get human form
295 mov si,err_notfound ; Complain about missing kernel
300 jmp abort_load ; Ask user for clue
303 ; on_error: bad kernel, but we have onerror set
314 pop di ; <E> di == command_line
315 pop bx ; <D> bx == [OnerrorLen]
316 je bad_kernel.really ; Onerror matches command_line already
317 neg bx ; bx == -[OnerrorLen]
318 lea cx,[max_cmd_len+bx]
319 ; CX == max_cmd_len-[OnerrorLen]
320 mov di,command_line+max_cmd_len-1
321 mov byte [di+1],0 ; Enforce null-termination
324 rep movsb ; Make space in command_line
326 pop cx ; <C> cx == [OnerrorLen]
327 pop di ; <B> di == command_line
328 pop si ; <A> si == Onerror
333 ; vk_found: We *are* using a "virtual kernel"
340 push es ; Restore old DS
343 push word real_mode_seg
346 mov si,VKernelBuf+vk_append
347 mov cx,[VKernelBuf+vk_appendlen]
349 mov [CmdLinePtr],di ; Where to add rest of cmd
351 pop di ; DI -> KernelName
353 mov si,VKernelBuf+vk_rname
354 mov cx,FILENAME_MAX ; We need ECX == CX later
358 mov al,[VKernelBuf+vk_ipappend]
361 xor bx,bx ; Try only one version
363 %if IS_SYSLINUX || IS_MDSLINUX
366 ; Is this a "localboot" pseudo-kernel?
367 cmp byte [VKernelBuf+vk_rname], 0
368 jne get_kernel ; No, it's real, go get it
370 mov ax, [VKernelBuf+vk_rname+1]
375 ; kernel_corrupt: Called if the kernel file does not seem healthy
377 kernel_corrupt: mov si,err_notkernel
380 ; This is it! We have a name (and location on the disk)... let's load
381 ; that sucker!! First we have to decide what kind of file this is; base
382 ; that decision on the file extension. The following extensions are
383 ; recognized; case insensitive:
385 ; .com - COMBOOT image
386 ; .cbt - COMBOOT image
389 ; .0 - PXE bootstrap program (PXELINUX only)
391 ; .bss - Boot sector, but transfer over DOS superblock (SYSLINUX only)
392 ; .img - Floppy image (ISOLINUX only)
394 ; Anything else is assumed to be a Linux kernel.
402 mov [KernelCNameLen],di
405 %if IS_SYSLINUX || IS_MDSLINUX
406 mov ecx,[KernelName+7]
417 .one_step: mov ecx,[di-4] ; 4 bytes before end
423 ; At this point, DX:AX contains the size of the kernel, and SI contains
424 ; the file handle/cluster pointer.
426 or ecx,20202000h ; Force lower case
442 %if IS_SYSLINUX || IS_MDSLINUX
455 ; Otherwise Linux kernel