Subversion Repositories HelenOS

#ifdef CONFIG_FB

#define MULTIBOOT_LOADER_MAGIC  0x2BADB002
#define MBINFO_BIT_CMDLINE      2
#define MBINFO_OFFSET_CMDLINE   16

    # copy real mode VESA initialization code
    
    mov $vesa_init, %esi
    mov $VESA_INIT_SEGMENT << 4, %edi
    mov $e_vesa_init - vesa_init, %ecx
    rep movsb
    
    # check for GRUB command line
    
    mov grub_eax, %eax
    cmp $MULTIBOOT_LOADER_MAGIC, %eax
    jne no_cmdline
    
    mov grub_ebx, %ebx
    mov (%ebx), %eax
    bt $MBINFO_BIT_CMDLINE, %eax
    jnc no_cmdline
    
    # skip the kernel path in command line
    
    mov MBINFO_OFFSET_CMDLINE(%ebx), %esi
    
    skip_loop:
        lodsb
        
        cmp $0, %al
        je no_cmdline
        
        cmp $' ', %al
        je skip_loop_done
        
        jmp skip_loop
    skip_loop_done:
    
    mov (%esi), %al
    cmp $0, %al
    je no_cmdline
    
    # copy at most 23 characters from command line
    
    mov $VESA_INIT_SEGMENT << 4, %edi
    add $default_mode - vesa_init, %edi
    mov $23, %ecx
    
    cmd_loop:
        lodsb
        stosb
        
        cmp $0, %al
        je cmd_loop_done
        
        loop cmd_loop
    cmd_loop_done:
    
    # zero termination
    
    xor %eax, %eax
    stosb
    
    no_cmdline:
    
    # jump to the real mode
    
    mov $VESA_INIT_SEGMENT << 4, %edi
    jmpl *%edi
    
    vesa_meeting_point:
        # returned back to protected mode
        
        mov %esi, KA2PA(vesa_ph_addr)
        mov %di, KA2PA(vesa_height)
        shr $16, %edi
        mov %di, KA2PA(vesa_width)
        mov %bx, KA2PA(vesa_scanline)
        shr $16, %ebx
        mov %bx, KA2PA(vesa_bpp)
#endif