Intravision/reactos
1
0
Fork 0
mirror of https://github.com/reactos/reactos.git synced 2025-02-22 16:36:33 +00:00
Code Issues Projects Releases Packages Wiki Activity

[NTVDM]: Implement PC reset handling in the BIOS. Used by some apps for switching from protected mode back to real mode the 286 way (see: http://www.rcollins.org/articles/pmbasics/ for more details).

Browse source 
svn path=/trunk/; revision=67601
This commit is contained in:
Hermès Bélusca-Maïto 2015-05-08 19:26:46 +00:00
parent ff8b29da1b
commit b86604cdde
2 changed files with 84 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
reactos/subsystems/mvdm/ntvdm/bios/bios.h
View file

@ -74,7 +74,13 @@ typedef struct
WORD CrtBasePort; // 0x63
BYTE CrtModeControl; // 0x65
BYTE CrtColorPaletteMask; // 0x66
BYTE CassetteData[5]; // 0x67
union // 0x67
{
BYTE CassetteData[5]; // Cassette tape control (unused)
DWORD ResumeEntryPoint; // CS:IP for 286 return from Protected Mode
};
DWORD TickCounter; // 0x6c
BYTE MidnightPassed; // 0x70
BYTE BreakFlag; // 0x71

84
reactos/subsystems/mvdm/ntvdm/bios/bios32/bios32.c
View file

@ -31,6 +31,7 @@
#include "hardware/cmos.h"
#include "hardware/pic.h"
#include "hardware/pit.h"
#include "hardware/ps2.h"
/* PRIVATE VARIABLES **********************************************************/
@ -131,7 +132,7 @@ static BYTE Bootstrap[] =
static BYTE PostCode[] =
{
LOBYTE(EMULATOR_BOP), HIBYTE(EMULATOR_BOP), BOP_RESET, // Call BIOS POST
0xCD, 0x19, // INT 0x19, the bootstrap loader interrupt
0xCD, BIOS_BOOTSTRAP_LOADER, // INT 0x19
// LOBYTE(EMULATOR_BOP), HIBYTE(EMULATOR_BOP), BOP_UNSIMULATE
};
@ -233,9 +234,9 @@ static VOID WINAPI BiosMiscService(LPWORD Stack)
* Return the (usable) extended memory (after 1 MB)
* size in kB from CMOS.
*/
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_ACTUAL_EXT_MEMORY_LOW);
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_ACTUAL_EXT_MEMORY_LOW | CMOS_DISABLE_NMI);
Low = IOReadB(CMOS_DATA_PORT);
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_ACTUAL_EXT_MEMORY_HIGH);
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_ACTUAL_EXT_MEMORY_HIGH | CMOS_DISABLE_NMI);
High = IOReadB(CMOS_DATA_PORT);
setAX(MAKEWORD(Low, High));
@ -607,9 +608,9 @@ static VOID InitializeBiosData(VOID)
* Retrieve the conventional memory size
* in kB from CMOS, typically 640 kB.
*/
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_BASE_MEMORY_LOW);
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_BASE_MEMORY_LOW | CMOS_DISABLE_NMI);
Low = IOReadB(CMOS_DATA_PORT);
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_BASE_MEMORY_HIGH);
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_BASE_MEMORY_HIGH | CMOS_DISABLE_NMI);
High = IOReadB(CMOS_DATA_PORT);
Bda->MemorySize = MAKEWORD(Low, High);
}
@ -640,6 +641,7 @@ Bios32Post(VOID)
#if 0
BOOLEAN Success;
#endif
BYTE ShutdownStatus;
DPRINT("Bios32Post\n");
@ -654,12 +656,80 @@ Bios32Post(VOID)
setDS(BDA_SEGMENT);
/*
* Perform early CMOS shutdown status checks
*/
/* Read the CMOS shutdown status byte and reset it */
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_SHUTDOWN_STATUS | CMOS_DISABLE_NMI);
ShutdownStatus = IOReadB(CMOS_DATA_PORT);
IOWriteB(CMOS_ADDRESS_PORT, CMOS_REG_SHUTDOWN_STATUS | CMOS_DISABLE_NMI);
IOWriteB(CMOS_DATA_PORT, 0x00);
DPRINT1("Bda->SoftReset = 0x%04X ; ShutdownStatus = 0x%02X\n",
Bda->SoftReset, ShutdownStatus);
switch (ShutdownStatus)
{
/* Shutdown after Memory Tests (unsupported) */
case 0x01: case 0x02: case 0x03:
/* Shutdown after Protected Mode Tests (unsupported) */
case 0x06: case 0x07: case 0x08:
/* Shutdown after Block Move Test (unsupported) */
case 0x09:
{
DisplayMessage(L"Unsupported CMOS Shutdown Status value 0x%02X. The VDM is stopping...", ShutdownStatus);
EmulatorTerminate();
return;
}
/* Shutdown to Boot Loader */
case 0x04:
{
DPRINT1("Fast restart to Bootstrap Loader...\n");
return;
}
/* Flush keyboard, issue an EOI... */
case 0x05:
{
IOReadB(PS2_DATA_PORT);
/* Send EOI */
IOWriteB(PIC_SLAVE_CMD , PIC_OCW2_EOI);
IOWriteB(PIC_MASTER_CMD, PIC_OCW2_EOI);
// Fall back
}
/*
* ... and far JMP to user-specified location at 0040:0067
* (Bda->ResumeEntryPoint) with interrupts and NMI disabled.
*/
case 0x0A:
{
DPRINT1("Bda->ResumeEntryPoint = %04X:%04X\n",
HIWORD(Bda->ResumeEntryPoint),
LOWORD(Bda->ResumeEntryPoint));
/* Position execution pointers to Bda->ResumeEntryPoint and return */
setCS(HIWORD(Bda->ResumeEntryPoint));
setIP(LOWORD(Bda->ResumeEntryPoint));
return;
}
/* Soft reset or unexpected shutdown... */
case 0x00:
/* ... or other possible shutdown codes: just continue the POST */
default:
break;
}
/*
* FIXME: UNIMPLEMENTED!
* Check the word at 0040h:0072h (Bda->SoftReset) and do one of the
* following actions:
* - if the word is 0000h, perform a cold reboot (aka. Reset). Everything gets initialized.
* - if the word is 1234h, perform a warm reboot (aka. Ctrl-Alt-Del). Some stuff is skipped.
* In case we do a warm reboot, we need to check for the CMOS shutdown flag
* and take a suitable action.
*/
// FIXME: This is a debug temporary check: