source: mainline/kernel/arch/ia32/src/boot/vesa_real.inc@ 3bacee1

#ifdef CONFIG_FB

#include <macros.h>

#define VESA_INFO_SIZE 1024

#define VESA_MODE_ATTRIBUTES_OFFSET  0
#define VESA_MODE_LIST_PTR_OFFSET    14
#define VESA_MODE_SCANLINE_OFFSET    16
#define VESA_MODE_WIDTH_OFFSET       18
#define VESA_MODE_HEIGHT_OFFSET      20
#define VESA_MODE_BPP_OFFSET         25
#define VESA_MODE_RED_MASK_OFFSET    31
#define VESA_MODE_RED_POS_OFFSET     32
#define VESA_MODE_GREEN_MASK_OFFSET  33
#define VESA_MODE_GREEN_POS_OFFSET   34
#define VESA_MODE_BLUE_MASK_OFFSET   35
#define VESA_MODE_BLUE_POS_OFFSET    36
#define VESA_MODE_PHADDR_OFFSET      40

#define VESA_END_OF_MODES  0xffff

#define VESA_OK  0x4f

#define VESA_GET_INFO       0x4f00
#define VESA_GET_MODE_INFO  0x4f01
#define VESA_SET_MODE       0x4f02
#define VESA_SET_PALETTE    0x4f09

.code32
vesa_init:
        lidtl vesa_idtr

        mov $GDT_SELECTOR(VESA_INIT_DATA_DES), %bx

        mov %bx, %es
        mov %bx, %fs
        mov %bx, %gs
        mov %bx, %ds
        mov %bx, %ss

        jmp $GDT_SELECTOR(VESA_INIT_CODE_DES), $vesa_init_real - vesa_init

vesa_idtr:
        .word 0x3ff
        .long 0

.code16
vesa_init_real:
        mov %cr0, %eax
        and $~CR0_PE, %eax
        mov %eax, %cr0

        jmp $VESA_INIT_SEGMENT, $vesa_init_real2 - vesa_init

vesa_init_real2:
        mov $VESA_INIT_SEGMENT, %bx

        mov %bx, %es
        mov %bx, %fs
        mov %bx, %gs
        mov %bx, %ds
        mov %bx, %ss

        movl %esp, %eax
        movl $0x0000fffc, %esp
        movl $0x0000fffc, %ebp
        pushl %eax

        /* Parse default mode string */

        mov $default_mode - vesa_init, %di
        xor %eax, %eax
        xor %ebx, %ebx

        mov $8, %ecx
        parse_width:
                mov (%di), %al

                /* Check for digit */

                cmp $'0', %al
                jb parse_width_done

                cmp $'9', %al
                ja parse_width_done

                sub $'0', %al

                /* Multiply default_width by 10 and add digit */

                mov default_width - vesa_init, %bx
                lea (%ebx, %ebx, 4), %ebx
                shl $1, %ebx
                add %ax, %bx
                mov %bx, default_width - vesa_init

                inc %di
                loop parse_width
        parse_width_done:

        mov (%di), %al
        cmp $0, %al
        jz parse_done
        inc %di

        mov $8, %ecx
        parse_height:
                mov (%di), %al

                /* Check for digit */

                cmp $'0', %al
                jb parse_height_done

                cmp $'9', %al
                ja parse_height_done

                sub $'0', %al

                /* Multiply default_height by 10 and add digit */

                mov default_height - vesa_init, %bx
                lea (%ebx, %ebx, 4), %ebx
                shl $1, %ebx
                add %ax, %bx
                mov %bx, default_height - vesa_init

                inc %di
                loop parse_height
        parse_height_done:

        mov (%di), %al
        cmp $0, %al
        jz parse_done
        inc %di

        mov $4, %ecx
        parse_bpp:
                mov (%di), %al

                /* Check for digit */

                cmp $'0', %al
                jb parse_bpp_done

                cmp $'9', %al
                ja parse_bpp_done

                sub $'0', %al

                /* Multiply default_bpp by 10 and add digit */

                mov default_bpp - vesa_init, %bx
                lea (%ebx, %ebx, 4), %ebx
                shl $1, %ebx
                add %ax, %bx
                mov %bx, default_bpp - vesa_init

                inc %di
                loop parse_bpp
        parse_bpp_done:

        parse_done:

        mov $VESA_GET_INFO, %ax
        mov $e_vesa_init - vesa_init, %di
        push %di
        /* Write the "VBE2" signature into the info structure in order
         * to get proper mode information. The presence of "VBE2"
         * indicates two things:
         *
         *  - VBE controller information structure is expected to be
         *    512 bytes long instead of 256 bytes.
         *  - The BIOS should report VBE 3.0 information (potentially
         *    including non-standard modes in the mode list).
         */
        movl $0x32454256, (%di)
        int $0x10

        pop %di
        cmp $VESA_OK, %al
        jnz no_mode

        mov 2 + VESA_MODE_LIST_PTR_OFFSET(%di), %si
        mov %si, %gs
        mov VESA_MODE_LIST_PTR_OFFSET(%di), %si

        add $VESA_INFO_SIZE, %di

        next_mode:
                /* Try next mode */

                mov %gs:(%si), %cx
                cmp $VESA_END_OF_MODES, %cx
                je no_mode

                inc %si
                inc %si
                push %cx
                push %di
                push %si
                mov $VESA_GET_MODE_INFO, %ax
                int $0x10

                pop %si
                pop %di
                pop %cx
                cmp $VESA_OK, %al
                jne no_mode

                /*
                 * Check for proper attributes (supported,
                 * color, graphics, linear framebuffer).
                 */

                mov VESA_MODE_ATTRIBUTES_OFFSET(%di), %ax
                and $0x99, %ax
                cmp $0x99, %ax
                jne next_mode

                /* Check for proper resolution */

                mov default_width - vesa_init, %ax
                cmp VESA_MODE_WIDTH_OFFSET(%di), %ax
                jne next_mode

                mov default_height - vesa_init, %ax
                cmp VESA_MODE_HEIGHT_OFFSET(%di), %ax
                jne next_mode

                /* Check for proper bpp */

                mov default_bpp - vesa_init, %al
                cmp VESA_MODE_BPP_OFFSET(%di), %al
                je set_mode

                mov $24, %al
                cmp default_bpp - vesa_init, %al
                jne next_mode

                /* For 24 bpp modes accept also 32 bit bpp */

                mov $32, %al
                cmp VESA_MODE_BPP_OFFSET(%di), %al
                jne next_mode

        set_mode:
                mov %cx, %bx
                or $0xc000, %bx
                push %di
                mov $VESA_SET_MODE, %ax
                int $0x10

                pop %di
                cmp $VESA_OK, %al
                jnz no_mode

                /* Set 3:2:3 VGA palette */

                mov VESA_MODE_BPP_OFFSET(%di), %al
                cmp $8, %al
                jnz vga_not_set

                mov VESA_MODE_ATTRIBUTES_OFFSET(%di), %ax
                push %di
                mov $vga323 - vesa_init, %di
                mov $0x100, %ecx

                /* Test if VGA compatible registers are present */
                bt $5, %ax
                jnc vga_compat

                        /* Use VESA routine to set the palette */

                        mov $VESA_SET_PALETTE, %ax
                        xor %bl, %bl
                        xor %dx, %dx
                        int $0x10

                        cmp $0x00, %ah
                        je vga_not_compat

                vga_compat:

                        /* Use VGA registers to set the palette */

                        movw $0x3c6, %dx  /* set palette mask */
                        movb $0xff, %al
                        outb %al, %dx

                        movw $0x3c8, %dx  /* first index to set */
                        xor %al, %al
                        outb %al, %dx

                        movw $0x3c9, %dx  /* data port */

                        vga_loop:
                                movb %es:2(%di), %al
                                outb %al, %dx

                                movb %es:1(%di), %al
                                outb %al, %dx

                                movb %es:(%di), %al
                                outb %al, %dx

                                addw $4, %di
                        loop vga_loop

                vga_not_compat:

                        pop %di

                vga_not_set:

                /*
                 * Store mode parameters:
                 *  eax = bpp[16] scanline[16]
                 *  ebx = width[16]  height[16]
                 *  edx = red_mask[8] red_pos[8] green_mask[8] green_pos[8]
                 *  esi = blue_mask[8] blue_pos[8]
                 *  edi = linear frame buffer
                 */

                mov VESA_MODE_BPP_OFFSET(%di), %al
                xor %ah, %ah
                shl $16, %eax
                mov VESA_MODE_SCANLINE_OFFSET(%di), %ax

                mov VESA_MODE_WIDTH_OFFSET(%di), %bx
                shl $16, %ebx
                mov VESA_MODE_HEIGHT_OFFSET(%di), %bx

                mov VESA_MODE_BLUE_MASK_OFFSET(%di), %dl
                shl $8, %edx
                mov VESA_MODE_BLUE_POS_OFFSET(%di), %dl
                mov %edx, %esi

                mov VESA_MODE_RED_MASK_OFFSET(%di), %dl
                shl $8, %edx
                mov VESA_MODE_RED_POS_OFFSET(%di), %dl

                shl $8, %edx
                mov VESA_MODE_GREEN_MASK_OFFSET(%di), %dl
                shl $8, %edx
                mov VESA_MODE_GREEN_POS_OFFSET(%di), %dl

                mov VESA_MODE_PHADDR_OFFSET(%di), %edi

                vesa_leave_real:

                        mov %cr0, %ecx
                        or $CR0_PE, %ecx
                        mov %ecx, %cr0

                        jmp vesa_leave_real2

                vesa_leave_real2:

                        ljmpl $GDT_SELECTOR(KTEXT32_DES), $(vesa_init_protected - vesa_init + VESA_INIT_SEGMENT << 4)

        no_mode:

                /* No prefered mode found */

                mov $0x111, %cx
                push %di
                push %cx
                mov $VESA_GET_MODE_INFO, %ax
                int $0x10

                pop %cx
                pop %di
                cmp $VESA_OK, %al
                jnz text_mode
                jz set_mode  /* force relative jump */

        text_mode:

                /* Reset to EGA text mode (because of problems with VESA) */

                mov $0x0003, %ax
                int $0x10

                xor %eax, %eax
                xor %ebx, %ebx
                xor %edx, %edx
                xor %edi, %edi

                jz vesa_leave_real  /* force relative jump */

vga323:
#include "vga323.pal"

default_width:
        .word 0

default_height:
        .word 0

default_bpp:
        .byte 0

default_mode:
        .ascii STRING(CONFIG_BFB_MODE)
        .ascii "-"
        .asciz STRING(CONFIG_BFB_BPP)
        .fill 24

#include "vesa_ret.inc"

.align 4
e_vesa_init:
#endif