void * VBEAPI VBE_getBankedPointer(VBE_modeInfo *modeInfo)
/****************************************************************************
*
* Function: VBE_getBankedPointer
* Parameters: modeInfo - Mode info block for video mode
* Returns: Selector to the linear framebuffer (0 on failure)
*
* Description: Returns a near pointer to the VGA framebuffer area.
*
****************************************************************************/
{
/* We just map the pointer every time, since the pointer will always
* be in real mode memory, so we wont actually be mapping any real
* memory.
*
* NOTE: We cannot currently map a near pointer to the banked frame
* buffer for Watcom Win386, so we create a 16:16 far pointer to
* the video memory. All the assembler code will render to the
* video memory by loading the selector rather than using a
* near pointer.
*/
ulong seg = (ushort)modeInfo->WinASegment;
if (seg != 0) {
if (seg == 0xA000)
return (void*)PM_getA0000Pointer();
else
return (void*)PM_mapPhysicalAddr(seg << 4,0xFFFF,true);
}
return NULL;
}
/****************************************************************************
REMARKS:
Read the font data from the VGA character generator RAM
****************************************************************************/
static void vga_saveFont(
uchar *data)
{
uchar *A0000Ptr = PM_getA0000Pointer();
uchar save[7];
/* Enable access to character generator RAM */
save[0] = (uchar)vga_rdinx(SEQ_I,0x00);
save[1] = (uchar)vga_rdinx(SEQ_I,0x02);
save[2] = (uchar)vga_rdinx(SEQ_I,0x04);
save[3] = (uchar)vga_rdinx(SEQ_I,0x00);
save[4] = (uchar)vga_rdinx(GRA_I,0x04);
save[5] = (uchar)vga_rdinx(GRA_I,0x05);
save[6] = (uchar)vga_rdinx(GRA_I,0x06);
vga_wrinx(SEQ_I,0x00,0x01);
vga_wrinx(SEQ_I,0x02,0x04);
vga_wrinx(SEQ_I,0x04,0x07);
vga_wrinx(SEQ_I,0x00,0x03);
vga_wrinx(GRA_I,0x04,0x02);
vga_wrinx(GRA_I,0x05,0x00);
vga_wrinx(GRA_I,0x06,0x00);
/* Copy character generator RAM */
memcpy(data,A0000Ptr,FONT_C);
/* Restore VGA state */
vga_wrinx(SEQ_I,0x00,save[0]);
vga_wrinx(SEQ_I,0x02,save[1]);
vga_wrinx(SEQ_I,0x04,save[2]);
vga_wrinx(SEQ_I,0x00,save[3]);
vga_wrinx(GRA_I,0x04,save[4]);
vga_wrinx(GRA_I,0x05,save[5]);
vga_wrinx(GRA_I,0x06,save[6]);
}
/****************************************************************************
REMARKS:
Downloads the font data to the VGA character generator RAM
****************************************************************************/
static void vga_restoreFont(
const uchar *data)
{
uchar *A0000Ptr = PM_getA0000Pointer();
/* Enable access to character generator RAM */
vga_wrinx(SEQ_I,0x00,0x01);
vga_wrinx(SEQ_I,0x02,0x04);
vga_wrinx(SEQ_I,0x04,0x07);
vga_wrinx(SEQ_I,0x00,0x03);
vga_wrinx(GRA_I,0x04,0x02);
vga_wrinx(GRA_I,0x05,0x00);
vga_wrinx(GRA_I,0x06,0x00);
/* Copy font back to character generator RAM */
memcpy(A0000Ptr,data,FONT_C);
}