vbe.h

#ifndef VBE_H
#define VBE_H

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>

#define VBE_DISPI_IOPORT_INDEX          0x01CE
#define VBE_DISPI_IOPORT_DATA           0x01CF
#define VBE_DISPI_INDEX_ID              0
#define VBE_DISPI_INDEX_XRES            1
#define VBE_DISPI_INDEX_YRES            2
#define VBE_DISPI_INDEX_BPP             3
#define VBE_DISPI_INDEX_BANK            5
#define VBE_DISPI_INDEX_VIRT_WIDTH      6
#define VBE_DISPI_INDEX_VIRT_HEIGHT     7
#define VBE_DISPI_INDEX_X_OFFSET        8
#define VBE_DISPI_INDEX_Y_OFFSET        9

#define VBE_DISPI_BPP_4                 0x04
#define VBE_DISPI_BPP_8                 0x08
#define VBE_DISPI_BPP_15                0x0F
#define VBE_DISPI_BPP_16                0x10
#define VBE_DISPI_BPP_24                0x18
#define VBE_DISPI_BPP_32                0x20

#define VBE_DISPI_DISABLED              0x00 
#define VBE_DISPI_ENABLED               0x01
#define VBE_DISPI_INDEX_ENABLE          0x04
#define VBE_DISPI_LFB_ENABLED           0x40
#define VBE_DISPI_NOCLEARMEM            0x80

#define VBE_DISPI_ID0                   0xB0C0
#define VBE_DISPI_ID1                   0xB0C1
#define VBE_DISPI_ID2                   0xB0C2
#define VBE_DISPI_ID3                   0xB0C3
#define VBE_DISPI_ID4                   0xB0C4
#define VBE_DISPI_ID5                   0xB0C5

#define VBE_DISPI_LFB_PHYSICAL_ADDRESS  0xA0000
#define BANK_SIZE                       0x10000

//typedef for VESA mode information
typedef struct vbe_mode_info {
        unsigned short mode_attributes      __attribute__((packed));
        unsigned char win_a_attributes;
        unsigned char win_b_attributes;
        unsigned short win_granularity      __attribute__((packed));
        unsigned short win_size             __attribute__((packed));
        unsigned short win_a_segment        __attribute__((packed));
        unsigned short win_b_segment        __attribute__((packed));
        unsigned long win_func_ptr          __attribute__((packed));
        unsigned short bytes_per_scan_line  __attribute__((packed));
        unsigned short x_res                __attribute__((packed));
        unsigned short y_res                __attribute__((packed));
        unsigned char x_char_size;
        unsigned char y_char_size;
        unsigned char num_planes;
        unsigned char bpp;
        unsigned char bank_num;
        unsigned char mem_model;
        unsigned char bank_size;
        unsigned char num_image_pages;
        unsigned char reserved_page;
        unsigned char red_mask_size;
        unsigned char red_mask_pos;
        unsigned char green_mask_size;
        unsigned char green_mask_pos;
        unsigned char blue_mask_size;
        unsigned char blue_mask_pos;
        unsigned char reserved_mask_size;
        unsigned char reserved_mask_pos;
        unsigned char direct_color_mode_info;
        unsigned long physbase              __attribute__((packed));
        unsigned long offscreen_mem_offset  __attribute__((packed));
        unsigned short offscreen_mem_size   __attribute__((packed));
        unsigned char reserved[256];
} vbe_mode_info;

typedef struct vesa_info {
        unsigned char vesa_signature[4];
        unsigned short vesa_version         __attribute__((packed));
        unsigned long oem_string_ptr        __attribute__((packed));
        unsigned char capabilities[4];
        unsigned long video_mode_ptr        __attribute__((packed));
        unsigned short total_memory         __attribute__((packed));
        unsigned short oem_software_rev     __attribute__((packed));
        unsigned long oem_vendor_name_ptr   __attribute__((packed));
        unsigned long oem_product_name_ptr  __attribute__((packed));
        unsigned long oem_product_rev_ptr   __attribute__((packed));
        unsigned char reserved[222];
        unsigned char oem_data[256];
} vesa_info;

//read/write to VBE registers
void vbe_write_reg(unsigned short idx, unsigned short val);
unsigned short vbe_read_reg(unsigned short idx);

//is VBE available in our environment?
bool vbe_available(void);

//switch video memory bank to 'bank_num'
void vbe_set_bank(unsigned short bank_num);

//perform VBE graphics mode switch using given parameters
//if 'use_lfb' is set pixels can be plotted directly onto a framebuffer
//if 'clear_vmem' is set we'll request VBE clear framebuffer before we recieve it
void vbe_set_video_mode(unsigned int width, unsigned int height, unsigned int depth, bool use_lfb, bool clear_vmem);

#endif