Reorganized DOS memory remapping slightly, so that the real-mode
interrupt table can exist even when low DOS memory isn't mapped,
and is copied down along with the BIOS area whenever it is mapped.
Added DOSMEM_SystemBase() which returns a pointer to the virtual
real-mode interrupt table and BIOS data segment.
Allowed DOSMEM_Init(TRUE) to be called more than once.
diff --git a/include/miscemu.h b/include/miscemu.h
index 07e25ec..61d9854 100644
--- a/include/miscemu.h
+++ b/include/miscemu.h
@@ -143,6 +143,7 @@
extern void DOSMEM_Tick(WORD timer);
extern WORD DOSMEM_AllocSelector(WORD);
extern char * DOSMEM_MemoryBase(void);
+extern char * DOSMEM_SystemBase(void);
extern LPVOID DOSMEM_GetBlock(UINT size, WORD* p);
extern BOOL DOSMEM_FreeBlock(void* ptr);
extern LPVOID DOSMEM_ResizeBlock(void* ptr, UINT size, WORD* p);
diff --git a/msdos/dosmem.c b/msdos/dosmem.c
index 6506fa1..cd2a9a2 100644
--- a/msdos/dosmem.c
+++ b/msdos/dosmem.c
@@ -64,8 +64,11 @@
/* DOS memory base */
static char *DOSMEM_dosmem;
-/* bios area; normally at offset 0x400, but can be moved to trap NULL pointers */
-static void *DOSMEM_biosdata;
+/* DOS system base (for interrupt vector table and BIOS data area)
+ * ...should in theory (i.e. Windows) be equal to DOSMEM_dosmem (NULL),
+ * but is normally set to 0xf0000 in Wine to allow trapping of NULL pointers,
+ * and only relocated to NULL when absolutely necessary */
+static char *DOSMEM_sysmem;
/* various real-mode code stubs */
WORD DOSMEM_wrap_seg;
@@ -74,6 +77,16 @@
WORD DOSMEM_dpmi_sel;
/***********************************************************************
+ * DOSMEM_SystemBase
+ *
+ * Gets the virtual DOS memory base (interrupt table).
+ */
+char *DOSMEM_SystemBase(void)
+{
+ return DOSMEM_sysmem;
+}
+
+/***********************************************************************
* DOSMEM_MemoryBase
*
* Gets the DOS memory base.
@@ -129,11 +142,17 @@
*/
static void DOSMEM_FillIsrTable(void)
{
- SEGPTR *isr = (SEGPTR*)DOSMEM_dosmem;
- DWORD *stub = (DWORD*)((char*)isr + (VM_STUB_SEGMENT << 4));
+ SEGPTR *isr = (SEGPTR*)DOSMEM_sysmem;
int x;
for (x=0; x<256; x++) isr[x]=PTR_SEG_OFF_TO_SEGPTR(VM_STUB_SEGMENT,x*4);
+}
+
+static void DOSMEM_MakeIsrStubs(void)
+{
+ DWORD *stub = (DWORD*)(DOSMEM_dosmem + (VM_STUB_SEGMENT << 4));
+ int x;
+
for (x=0; x<256; x++) stub[x]=VM_STUB(x);
}
@@ -198,7 +217,7 @@
BIOSDATA * DOSMEM_BiosData()
{
- return (BIOSDATA *)DOSMEM_biosdata;
+ return (BIOSDATA *)(DOSMEM_sysmem + 0x400);
}
BYTE * DOSMEM_BiosSys()
@@ -429,7 +448,7 @@
*/
static void setup_dos_mem( int dos_init )
{
- int bios_offset = 0x400;
+ int sys_offset = 0;
int page_size = VIRTUAL_GetPageSize();
void *addr = VIRTUAL_mmap( -1, (void *)page_size, 0x110000-page_size, 0,
PROT_READ | PROT_WRITE | PROT_EXEC, 0 );
@@ -451,8 +470,8 @@
if (!dos_init)
{
VirtualProtect( addr, 0x10000, PAGE_NOACCESS, NULL );
- /* move the BIOS data from 0x400 to 0xf0400 */
- bios_offset += 0xf0000;
+ /* move the BIOS and ISR area from 0x00000 to 0xf0000 */
+ sys_offset += 0xf0000;
}
}
else
@@ -468,7 +487,7 @@
}
}
DOSMEM_dosmem = addr;
- DOSMEM_biosdata = (char *)addr + bios_offset;
+ DOSMEM_sysmem = (char*)addr + sys_offset;
}
@@ -480,19 +499,20 @@
*/
BOOL DOSMEM_Init(BOOL dos_init)
{
- static int already_done;
+ static int already_done, already_mapped;
if (!already_done)
{
setup_dos_mem( dos_init );
- DOSMEM_0000H = GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_biosdata - 0x400,
+ DOSMEM_0000H = GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_sysmem,
0x10000, 0, FALSE, FALSE, FALSE );
- DOSMEM_BiosDataSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_biosdata,
+ DOSMEM_BiosDataSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_sysmem + 0x400,
0x100, 0, FALSE, FALSE, FALSE );
DOSMEM_BiosSysSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_dosmem+0xf0000,
0x10000, 0, FALSE, FALSE, FALSE );
DOSMEM_FillBiosSegments();
+ DOSMEM_FillIsrTable();
DOSMEM_InitMemory();
DOSMEM_InitCollateTable();
DOSMEM_InitErrorTable();
@@ -500,7 +520,7 @@
DOSDEV_InstallDOSDevices();
already_done = 1;
}
- else if (dos_init)
+ else if (dos_init && !already_mapped)
{
if (DOSMEM_dosmem)
{
@@ -510,14 +530,16 @@
MESSAGE( "Warning: unprotecting the first 64KB of memory to allow real-mode calls.\n"
" NULL pointer accesses will no longer be caught.\n" );
VirtualProtect( NULL, 0x10000, PAGE_EXECUTE_READWRITE, NULL );
- /* copy the BIOS area down to 0x400 */
- memcpy( DOSMEM_dosmem + 0x400, DOSMEM_biosdata, 0x100 );
- DOSMEM_biosdata = DOSMEM_dosmem + 0x400;
+ /* copy the BIOS and ISR area down */
+ memcpy( DOSMEM_dosmem, DOSMEM_sysmem, 0x400 + 0x100 );
+ DOSMEM_sysmem = DOSMEM_dosmem;
SetSelectorBase( DOSMEM_0000H, 0 );
SetSelectorBase( DOSMEM_BiosDataSeg, 0x400 );
+ /* we may now need the actual interrupt stubs, and since we've just moved the
+ * interrupt vector table away, we can fill the area with stubs instead... */
+ DOSMEM_MakeIsrStubs();
+ already_mapped = 1;
}
- /* interrupt table is at addr 0, so only do this when setting up DOS mode */
- if (dos_init) DOSMEM_FillIsrTable();
return TRUE;
}
