#include "eel.h"
#include "lowlevel.h"

typedef struct vesa_info {
    char    vesa[4];
    short   version;
    int     OEM_name;
    char    caps[4];
    int     modes;
    char    resv[238];
} VESA_INFO;

/* int to far pointer conversion structure */
/* related to the EEL_PTR structure in lowlevel.h */
typedef struct {
    int     base,
            size,
            value;
} EEL_POINTER;

set_eel_pointer(p, base, size, value)
    EEL_POINTER *p;
  {
    p->base = base;
    p->size = size;
    p->value = value;
  }

/* active = 2 - test for availability of this mode  */
/* active = 1 - set video to this mode              */
/* active = 0 - turn off this mode                  */ 
/* video.e already supports the 80x60 mode (0x108)  */
video_vesa_mode(mode, active)
  {     
    int         i;
    short       *mp;
    VESA_INFO   info;
    
    switch (active) {
    case 2:                                 /* test for support */
        m_regs.w.es = get_pointer(&info, SEGMENT);
        m_regs.w.di = get_pointer(&info, OFFSET);
        vid_int(0x4F00);                    /* get superVGA information */
        if (m_regs.w.ax != 0x004F || !info.modes || strncmp(info.vesa, "VESA", 4))
            return 0;
        set_eel_pointer(&mp, info.modes, 1024, info.modes);
        for (i = 0; i < 256 && mp[i] != -1; i++)
            if (mp[i] == mode)              /* find this mode in the array */
                return 1;
        break;
    case 1:                                 /* set this mode */
        m_regs.w.bx = mode;
        vid_int(0x4F02);                    /* set superVGA video mode */
        if (m_regs.w.ax == 0x004F)             
            return 1;
        break;
    case 0:                                 /* terminate mode */
        vid_int(video_normal_mode());		/* set mode to 80x25 */
        vid_bright_back(1);
        leave_blank = 1;
        return 1;
    }
    return 0;                               /* failure */
  }

video_mode_132x25(active)
  {
    return video_vesa_mode(0x109, active);
  }

video_mode_132x43(active)
  {
    return video_vesa_mode(0x10A, active);
  }

video_mode_132x50(active)
  {
    return video_vesa_mode(0x10B, active);
  }

video_mode_132x60(active)
  {
    return video_vesa_mode(0x10C, active);
  }