rom.c File Reference

#include "ntvdm.h"
#include <debug.h>
#include "emulator.h"
#include "memory.h"
#include "cpu/callback.h"
#include "rom.h"
#include "utils.h"

Include dependency graph for rom.c:

Go to the source code of this file.

Macros
#define	NDEBUG

Functions
static BOOLEAN FASTCALL	ShadowRomWrite (ULONG Address, PVOID Buffer, ULONG Size)
static HANDLE	OpenRomFile (IN PCSTR RomFileName, OUT PULONG RomSize OPTIONAL)
static BOOLEAN	LoadRomFileByHandle (IN HANDLE RomFileHandle, IN PVOID RomLocation, IN ULONG RomSize, OUT PULONG BytesRead)
static VOID	InitRomRange (IN PCALLBACK16 Context, IN ULONG Start, IN ULONG End, IN ULONG Increment)
BOOLEAN	WriteProtectRom (IN PVOID RomLocation, IN ULONG RomSize)
BOOLEAN	WriteUnProtectRom (IN PVOID RomLocation, IN ULONG RomSize)
UCHAR	CalcRomChecksum (IN ULONG RomLocation, IN ULONG RomSize)
BOOLEAN	LoadBios (IN PCSTR BiosFileName, OUT PVOID *BiosLocation OPTIONAL, OUT PULONG BiosSize OPTIONAL)
BOOLEAN	LoadRom (IN PCSTR RomFileName, IN PVOID RomLocation, OUT PULONG RomSize OPTIONAL)
VOID	SearchAndInitRoms (IN PCALLBACK16 Context)

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 13 of file rom.c.

Function Documentation

CalcRomChecksum()

UCHAR CalcRomChecksum	(	IN ULONG	RomLocation,
		IN ULONG	RomSize
	)

Definition at line 153 of file rom.c.

{
    ULONG RomLastAddress = RomLocation + RomSize;
    UCHAR Sum = 0x00;   // Using a UCHAR guarantees that we wrap at 0xFF i.e. we do a sum modulo 0x100.
 
    while (RomLocation < RomLastAddress)
    {
        Sum += *(PUCHAR)REAL_TO_PHYS(RomLocation);
        ++RomLocation;
    }
 
    return Sum;
}

Referenced by InitRomRange(), and VidBiosInitialize().

InitRomRange()

static VOID InitRomRange ( IN PCALLBACK16  Context, IN ULONG  Start, IN ULONG  End, IN ULONG  Increment  )

static

Definition at line 87 of file rom.c.

{
    ULONG Address, EntryPoint;
    ULONG RomSize;
    UCHAR Checksum;
 
    for (Address = Start; Address < End; Address += Increment)
    {
        /* Does the ROM have a valid signature? */
        if (*(PUSHORT)REAL_TO_PHYS(Address) == OPTION_ROM_SIGNATURE)
        {
            /* Check the control sum of the ROM */
 
            /*
             * If this is an adapter ROM (Start: C8000, End: E0000),
             * its reported size is stored in byte 2 of the ROM.
             *
             * If this is an expansion ROM (Start: E0000, End: F0000),
             * its real length is 64kB.
             */
            RomSize = *(PUCHAR)REAL_TO_PHYS(Address + 2) * 512; // Size in blocks of 512 bytes
            if (Address >= 0xE0000) RomSize = 0x10000;
 
            Checksum = CalcRomChecksum(Address, RomSize);
            if (Checksum == 0x00)
            {
                EntryPoint = Address + 3;
                DPRINT1("Going to run @ address 0x%p\n", EntryPoint);
 
                EntryPoint = MAKELONG((EntryPoint & 0xFFFF), (EntryPoint & 0xF0000) >> 4);
                // setDS((Address & 0xF0000) >> 4);
                setDS((Address & 0xFF000) >> 4);
                RunCallback16(Context, EntryPoint);
                // Call16((EntryPoint & 0xF0000) >> 4, (EntryPoint & 0xFFFF));
 
                DPRINT1("ROM @ address 0x%p initialized\n", Address);
            }
            else
            {
                DPRINT1("ROM @ address 0x%p has invalid checksum of 0x%02x\n", Address, Checksum);
            }
        }
    }
}

Referenced by SearchAndInitRoms().

LoadBios()

BOOLEAN LoadBios	(	IN PCSTR	BiosFileName,
		OUT PVOID *BiosLocation	OPTIONAL,
		OUT PULONG BiosSize	OPTIONAL
	)

Definition at line 169 of file rom.c.

{
    BOOLEAN Success;
    HANDLE  hBiosFile;
    ULONG   ulBiosSize = 0;
    PVOID   pBiosLocation;
 
    /* Open the BIOS image file */
    hBiosFile = OpenRomFile(BiosFileName, &ulBiosSize);
 
    /* If we failed, bail out */
    if (hBiosFile == NULL) return FALSE;
 
    /* BIOS location needs to be aligned on 32-bit boundary */
    // (PVOID)((ULONG_PTR)BaseAddress + ROM_AREA_END + 1 - ulBiosSize)
    pBiosLocation = MEM_ALIGN_DOWN(TO_LINEAR(0xF000, 0xFFFF) + 1 - ulBiosSize, sizeof(ULONG));
 
    /* Attempt to load the BIOS image file into memory */
    Success = LoadRomFileByHandle(hBiosFile,
                                  pBiosLocation,
                                  ulBiosSize,
                                  &ulBiosSize);
    DPRINT1("BIOS loading %s ; GetLastError() = %u\n", Success ? "succeeded" : "failed", GetLastError());
 
    /* Close the BIOS image file */
    FileClose(hBiosFile);
 
    /*
     * In case of success, write-protect the BIOS location
     * and return the BIOS location and its size if needed.
     */
    if (Success)
    {
        WriteProtectRom(pBiosLocation, ulBiosSize);
 
        if (BiosLocation) *BiosLocation = pBiosLocation;
        if (BiosSize)     *BiosSize     = ulBiosSize;
    }
 
    return Success;
}

Referenced by BiosInitialize().

LoadRom()

BOOLEAN LoadRom	(	IN PCSTR	RomFileName,
		IN PVOID	RomLocation,
		OUT PULONG RomSize	OPTIONAL
	)

Definition at line 214 of file rom.c.

{
    BOOLEAN Success;
    HANDLE  hRomFile;
    ULONG   ulRomSize = 0;
 
    /* Open the ROM image file */
    hRomFile = OpenRomFile(RomFileName, &ulRomSize);
 
    /* If we failed, bail out */
    if (hRomFile == NULL) return FALSE;
 
    /* Attempt to load the ROM image file into memory */
    Success = LoadRomFileByHandle(hRomFile,
                                  RomLocation,
                                  ulRomSize,
                                  &ulRomSize);
    DPRINT1("ROM loading %s ; GetLastError() = %u\n", Success ? "succeeded" : "failed", GetLastError());
 
    /* Close the ROM image file and return */
    FileClose(hRomFile);
 
    /*
     * In case of success, write-protect the ROM location
     * and return the ROM size if needed.
     */
    if (Success)
    {
        WriteProtectRom(RomLocation, ulRomSize);
        if (RomSize) *RomSize = ulRomSize;
    }
 
    return Success;
}

Referenced by BiosInitialize().

LoadRomFileByHandle()

static BOOLEAN LoadRomFileByHandle ( IN HANDLE  RomFileHandle, IN PVOID  RomLocation, IN ULONG  RomSize, OUT PULONG  BytesRead  )

static

Definition at line 63 of file rom.c.

{
    /*
     * The size of the ROM image file is at most 256kB. For instance,
     * the SeaBIOS image, which includes also expansion ROMs inside it,
     * covers the range C000:0000 to F000:FFFF .
     */
    if (RomSize > 0x40000)
    {
        DPRINT1("ROM image size 0x%lx too large, expected at most 0x40000 (256kB)\n", RomSize);
        return FALSE;
    }
 
    /* Attempt to load the ROM image file into memory */
    return FileLoadByHandle(RomFileHandle,
                            REAL_TO_PHYS(RomLocation),
                            RomSize,
                            BytesRead);
}

Referenced by LoadBios(), and LoadRom().

OpenRomFile()

static HANDLE OpenRomFile ( IN PCSTR  RomFileName, OUT PULONG RomSize  OPTIONAL  )

static

Definition at line 32 of file rom.c.

{
    HANDLE hRomFile;
    ULONG  ulRomSize = 0;
 
    /* Open the ROM image file */
    hRomFile = FileOpen(RomFileName, &ulRomSize);
 
    /* If we failed, bail out */
    if (hRomFile == NULL) return NULL;
 
    /*
     * The size of the ROM image file is at most 256kB. For instance,
     * the SeaBIOS image, which includes also expansion ROMs inside it,
     * covers the range C000:0000 to F000:FFFF .
     */
    if (ulRomSize > 0x40000)
    {
        /* We failed, bail out */
        DPRINT1("ROM image size 0x%lx too large, expected at most 0x40000 (256kB)\n", ulRomSize);
        FileClose(hRomFile);
        return NULL;
    }
 
    /* Success, return file handle and size if needed */
    if (RomSize) *RomSize = ulRomSize;
    return hRomFile;
}

Referenced by LoadBios(), and LoadRom().

SearchAndInitRoms()

VOID SearchAndInitRoms

(

IN PCALLBACK16

Context

)

Definition at line 252 of file rom.c.

{
    /* Video ROMs -- Start: C0000, End: C8000, 2kB blocks */
    InitRomRange(Context, 0xC0000, 0xC8000, 0x0800);
 
    /* Adapters ROMs -- Start: C8000, End: E0000, 2kB blocks */
    InitRomRange(Context, 0xC8000, 0xE0000, 0x0800);
 
    /* Expansion ROM -- Start: E0000, End: F0000, 64kB block */
    InitRomRange(Context, 0xE0000, 0xEFFFF, 0x10000);
}

Referenced by Bios32Post().

ShadowRomWrite()

static BOOLEAN FASTCALL ShadowRomWrite ( ULONG  Address, PVOID  Buffer, ULONG  Size  )

static

Definition at line 25 of file rom.c.

{
    /* Prevent writing to ROM */
    return FALSE;
}

Referenced by WriteProtectRom().

WriteProtectRom()

BOOLEAN WriteProtectRom	(	IN PVOID	RomLocation,
		IN ULONG	RomSize
	)

Definition at line 138 of file rom.c.

{
    return MemInstallFastMemoryHook(RomLocation, RomSize,
                                    NULL, ShadowRomWrite);
}

Referenced by Bios32Initialize(), LoadBios(), LoadRom(), and VidBiosInitialize().

WriteUnProtectRom()

BOOLEAN WriteUnProtectRom	(	IN PVOID	RomLocation,
		IN ULONG	RomSize
	)

Definition at line 146 of file rom.c.

{
    return MemRemoveFastMemoryHook(RomLocation, RomSize);
}