vesavbe.c

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/****************************************************************************
*
*           The SuperVGA Kit - UniVBE Software Development Kit
*
*  ========================================================================
*
*    The contents of this file are subject to the SciTech MGL Public
*    License Version 1.0 (the "License"); you may not use this file
*    except in compliance with the License. You may obtain a copy of
*    the License at http://www.scitechsoft.com/mgl-license.txt
*
*    Software distributed under the License is distributed on an
*    "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
*    implied. See the License for the specific language governing
*    rights and limitations under the License.
*
*    The Original Code is Copyright (C) 1991-1998 SciTech Software, Inc.
*
*    The Initial Developer of the Original Code is SciTech Software, Inc.
*    All Rights Reserved.
*
*  ========================================================================
*
* Language:     ANSI C
* Environment:  IBM PC Real Mode and 16/32 bit Protected Mode.
*
* Description:  Module to implement a C callable interface to the standard
*               VESA VBE routines. You should rip out this module and use it
*               directly in your own applications, or you can use the
*               high level SDK functions.
*
*               MUST be compiled in the LARGE or FLAT models.
*
****************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "vesavbe.h"
#include "pmapi.h"
#include "drvlib/os/os.h"

/*---------------------------- Global Variables ---------------------------*/

#define VBE_SUCCESS     0x004F
#define MAX_LIN_PTRS    10

static uint         VESABuf_len = 1024;/* Length of the VESABuf buffer  */
static ibool        haveRiva128;    /* True if we have a Riva128        */
static VBE_state    defState = {0}; /* Default state buffer             */
static VBE_state    *state = &defState; /* Pointer to current buffer    */
static int          VBE_shared = 0;
#ifndef REALMODE
static char         localBuf[512];  /* Global PM string translate buf   */
#define MAX_LOCAL_BUF &localBuf[511]
#endif

/*----------------------------- Implementation ----------------------------*/

/* static function in WinDirect for passing 32-bit registers to BIOS */
int PMAPI WD_int386(int intno, RMREGS *in, RMREGS *out);

void VBEAPI VBE_init(void)
/****************************************************************************
*
* Function:     VBE_init
*
* Description:  Initialises the VBE transfer buffer in real mode DC.memory.
*               This routine is called by the VESAVBE module every time
*               it needs to use the transfer buffer, so we simply allocate
*               it once and then return.
*
****************************************************************************/
{
    if (!state->VESABuf_ptr) {
	/* Allocate a global buffer for communicating with the VESA VBE */
	if ((state->VESABuf_ptr = PM_getVESABuf(&VESABuf_len, &state->VESABuf_rseg, &state->VESABuf_roff)) == NULL)
	    PM_fatalError("VESAVBE.C: Real mode memory allocation failed!");
	}
}

void * VBEAPI VBE_getRMBuf(uint *len,uint *rseg,uint *roff)
/****************************************************************************
*
* Function:     VBE_getRMBuf
*
* Description:  This function returns the location and length of the real
*               mode memory buffer for calling real mode functions.
*
****************************************************************************/
{
    *len = VESABuf_len;
    *rseg = state->VESABuf_rseg;
    *roff = state->VESABuf_roff;
    return state->VESABuf_ptr;
}

void VBEAPI VBE_setStateBuffer(VBE_state *s)
/****************************************************************************
*
* Function:     VBE_setStateBuffer
*
* Description:  This functions sets the internal state buffer for the
*               VBE module to the passed in buffer. By default the internal
*               global buffer is used, but you must use separate buffers
*               for each device in a multi-controller environment.
*
****************************************************************************/
{
    state = s;
}

void VBEAPI VBE_callESDI(RMREGS *regs, void *buffer, int size)
/****************************************************************************
*
* Function:     VBE_callESDI
* Parameters:   regs    - Registers to load when calling VBE
*               buffer  - Buffer to copy VBE info block to
*               size    - Size of buffer to fill
*
* Description:  Calls the VESA VBE and passes in a buffer for the VBE to
*               store information in, which is then copied into the users
*               buffer space. This works in protected mode as the buffer
*               passed to the VESA VBE is allocated in conventional
*               memory, and is then copied into the users memory block.
*
****************************************************************************/
{
    RMSREGS sregs;

    if (!state->VESABuf_ptr)
	PM_fatalError("You *MUST* call VBE_init() before you can call the VESAVBE.C module!");
    sregs.es = (ushort)state->VESABuf_rseg;
    regs->x.di = (ushort)state->VESABuf_roff;
    memcpy(state->VESABuf_ptr, buffer, size);
    PM_int86x(0x10, regs, regs, &sregs);
    memcpy(buffer, state->VESABuf_ptr, size);
}

#ifndef REALMODE
static char *VBE_copyStrToLocal(char *p,char *realPtr,char *max)
/****************************************************************************
*
* Function:     VBE_copyStrToLocal
* Parameters:   p       - Flat model buffer to copy to
*               realPtr - Real mode pointer to copy
* Returns:      Pointer to the next byte after string
*
* Description:  Copies the string from the real mode location pointed to
*               by 'realPtr' into the flat model buffer pointed to by
*               'p'. We return a pointer to the next byte past the copied
*               string.
*
****************************************************************************/
{
    uchar   *v;

    v = PM_mapRealPointer((uint)((ulong)realPtr >> 16), (uint)((ulong)realPtr & 0xFFFF));
    while (*v != 0 && p < max)
	*p++ = *v++;
    *p++ = 0;
    return p;
}

static void VBE_copyShortToLocal(ushort *p,ushort *realPtr)
/****************************************************************************
*
* Function:     VBE_copyShortToLocal
* Parameters:   p       - Flat model buffer to copy to
*               realPtr - Real mode pointer to copy
*
* Description:  Copies the mode table from real mode memory to the flat
*               model buffer.
*
****************************************************************************/
{
    ushort  *v;

    v = PM_mapRealPointer((uint)((ulong)realPtr >> 16),(uint)((ulong)realPtr & 0xFFFF));
    while (*v != 0xFFFF)
	*p++ = *v++;
    *p = 0xFFFF;
}
#endif

int VBEAPI VBE_detectEXT(VBE_vgaInfo *vgaInfo,ibool forceUniVBE)
/****************************************************************************
*
* Function:     VBE_detect
* Parameters:   vgaInfo - Place to store the VGA information block
* Returns:      VBE version number, or 0 if not detected.
*
* Description:  Detects if a VESA VBE is out there and functioning
*               correctly. If we detect a VBE interface we return the
*               VGAInfoBlock returned by the VBE and the VBE version number.
*
****************************************************************************/
{
    RMREGS  regs;

    regs.x.ax = 0x4F00;     /* Get SuperVGA information */
    if (forceUniVBE) {
	regs.x.bx = 0x1234;
	regs.x.cx = 0x4321;
	}
    else {
	regs.x.bx = 0;
	regs.x.cx = 0;
	}
    strncpy(vgaInfo->VESASignature,"VBE2",4);
    VBE_callESDI(&regs, vgaInfo, sizeof(*vgaInfo));
    if (regs.x.ax != VBE_SUCCESS)
	return 0;
    if (strncmp(vgaInfo->VESASignature,"VESA",4) != 0)
	return 0;

    /* Check for bogus BIOSes that return a VBE version number that is
     * not correct, and fix it up. We also check the OemVendorNamePtr for a
     * valid value, and if it is invalid then we also reset to VBE 1.2.
     */
    if (vgaInfo->VESAVersion >= 0x200 && vgaInfo->OemVendorNamePtr == 0)
	vgaInfo->VESAVersion = 0x102;
#ifndef REALMODE
    /* Relocate all the indirect information (mode tables, OEM strings
     * etc) from the low 1Mb memory region into a static buffer in
     * our default data segment. We do this to insulate the application
     * from mapping the strings from real mode to protected mode.
     */
    {
	char *p,*p2;
     p2 = VBE_copyStrToLocal(localBuf,vgaInfo->OemStringPtr,MAX_LOCAL_BUF);
     vgaInfo->OemStringPtr = localBuf;
     if (vgaInfo->VESAVersion >= 0x200) {
	 p = VBE_copyStrToLocal(p2,vgaInfo->OemVendorNamePtr,MAX_LOCAL_BUF);
	 vgaInfo->OemVendorNamePtr = p2;
	 p2 = VBE_copyStrToLocal(p,vgaInfo->OemProductNamePtr,MAX_LOCAL_BUF);
	 vgaInfo->OemProductNamePtr = p;
	 p = VBE_copyStrToLocal(p2,vgaInfo->OemProductRevPtr,MAX_LOCAL_BUF);
	 vgaInfo->OemProductRevPtr = p2;
	 VBE_copyShortToLocal((ushort*)p,vgaInfo->VideoModePtr);
	 vgaInfo->VideoModePtr = (ushort*)p;
	 }
     else {
	 VBE_copyShortToLocal((ushort*)p2,vgaInfo->VideoModePtr);
	 vgaInfo->VideoModePtr = (ushort*)p2;
	 }
    }
#endif
    state->VBEMemory = vgaInfo->TotalMemory * 64;

    /* Check for Riva128 based cards since they have broken triple buffering
     * and stereo support.
     */
    haveRiva128 = false;
    if (vgaInfo->VESAVersion >= 0x300 &&
	   (strstr(vgaInfo->OemStringPtr,"NVidia") != NULL ||
	    strstr(vgaInfo->OemStringPtr,"Riva") != NULL)) {
	haveRiva128 = true;
	}

    /* Check for Matrox G400 cards which claim to be VBE 3.0
     * compliant yet they don't implement the refresh rate control
     * functions.
     */
    if (vgaInfo->VESAVersion >= 0x300 && (strcmp(vgaInfo->OemProductNamePtr,"Matrox G400") == 0))
	vgaInfo->VESAVersion = 0x200;
    return (state->VBEVersion = vgaInfo->VESAVersion);
}

int VBEAPI VBE_detect(VBE_vgaInfo *vgaInfo)
/****************************************************************************
*
* Function:     VBE_detect
* Parameters:   vgaInfo - Place to store the VGA information block
* Returns:      VBE version number, or 0 if not detected.
*
* Description:  Detects if a VESA VBE is out there and functioning
*               correctly. If we detect a VBE interface we return the
*               VGAInfoBlock returned by the VBE and the VBE version number.
*
****************************************************************************/
{
    return VBE_detectEXT(vgaInfo,false);
}

ibool VBEAPI VBE_getModeInfo(int mode,VBE_modeInfo *modeInfo)
/****************************************************************************
*
* Function:     VBE_getModeInfo
* Parameters:   mode        - VBE mode to get information for
*               modeInfo    - Place to store VBE mode information
* Returns:      True on success, false if function failed.
*
* Description:  Obtains information about a specific video mode from the
*               VBE. You should use this function to find the video mode
*               you wish to set, as the new VBE 2.0 mode numbers may be
*               completely arbitrary.
*
****************************************************************************/
{
    RMREGS  regs;
    int     bits;

    regs.x.ax = 0x4F01;             /* Get mode information         */
    regs.x.cx = (ushort)mode;
    VBE_callESDI(&regs, modeInfo, sizeof(*modeInfo));
    if (regs.x.ax != VBE_SUCCESS)
	return false;
    if ((modeInfo->ModeAttributes & vbeMdAvailable) == 0)
	return false;

    /* Map out triple buffer and stereo flags for NVidia Riva128
     * chips.
     */
    if (haveRiva128) {
	modeInfo->ModeAttributes &= ~vbeMdTripleBuf;
	modeInfo->ModeAttributes &= ~vbeMdStereo;
	}

    /* Support old style RGB definitions for VBE 1.1 BIOSes */
    bits = modeInfo->BitsPerPixel;
    if (modeInfo->MemoryModel == vbeMemPK && bits > 8) {
	modeInfo->MemoryModel = vbeMemRGB;
	switch (bits) {
	    case 15:
		modeInfo->RedMaskSize = 5;
		modeInfo->RedFieldPosition = 10;
		modeInfo->GreenMaskSize = 5;
		modeInfo->GreenFieldPosition = 5;
		modeInfo->BlueMaskSize = 5;
		modeInfo->BlueFieldPosition = 0;
		modeInfo->RsvdMaskSize = 1;
		modeInfo->RsvdFieldPosition = 15;
		break;
	    case 16:
		modeInfo->RedMaskSize = 5;
		modeInfo->RedFieldPosition = 11;
		modeInfo->GreenMaskSize = 5;
		modeInfo->GreenFieldPosition = 5;
		modeInfo->BlueMaskSize = 5;
		modeInfo->BlueFieldPosition = 0;
		modeInfo->RsvdMaskSize = 0;
		modeInfo->RsvdFieldPosition = 0;
		break;
	    case 24:
		modeInfo->RedMaskSize = 8;
		modeInfo->RedFieldPosition = 16;
		modeInfo->GreenMaskSize = 8;
		modeInfo->GreenFieldPosition = 8;
		modeInfo->BlueMaskSize = 8;
		modeInfo->BlueFieldPosition = 0;
		modeInfo->RsvdMaskSize = 0;
		modeInfo->RsvdFieldPosition = 0;
		break;
	    }
	}

    /* Convert the 32k direct color modes of VBE 1.2+ BIOSes to
     * be recognised as 15 bits per pixel modes.
     */
    if (bits == 16 && modeInfo->RsvdMaskSize == 1)
	modeInfo->BitsPerPixel = 15;

    /* Fix up bogus BIOS'es that report incorrect reserved pixel masks
     * for 32K color modes. Quite a number of BIOS'es have this problem,
     * and this affects our OS/2 drivers in VBE fallback mode.
     */
    if (bits == 15 && (modeInfo->RsvdMaskSize != 1 || modeInfo->RsvdFieldPosition != 15)) {
	modeInfo->RsvdMaskSize = 1;
	modeInfo->RsvdFieldPosition = 15;
	}
    return true;
}

long VBEAPI VBE_getPageSize(VBE_modeInfo *mi)
/****************************************************************************
*
* Function:     VBE_getPageSize
* Parameters:   mi  - Pointer to mode information block
* Returns:      Caculated page size in bytes rounded to correct boundary
*
* Description:  Computes the page size in bytes for the specified mode
*               information block, rounded up to the appropriate boundary
*               (8k, 16k, 32k or 64k). Pages >= 64k in size are always
*               rounded to the nearest 64k boundary (so the start of a
*               page is always bank aligned).
*
****************************************************************************/
{
    long size;

    size = (long)mi->BytesPerScanLine * (long)mi->YResolution;
    if (mi->BitsPerPixel == 4) {
	/* We have a 16 color video mode, so round up the page size to
	 * 8k, 16k, 32k or 64k boundaries depending on how large it is.
	 */

	size = (size + 0x1FFFL) & 0xFFFFE000L;
	if (size != 0x2000) {
	    size = (size + 0x3FFFL) & 0xFFFFC000L;
	    if (size != 0x4000) {
		size = (size + 0x7FFFL) & 0xFFFF8000L;
		if (size != 0x8000)
		    size = (size + 0xFFFFL) & 0xFFFF0000L;
		}