Intravision/reactos
1
0
Fork 0
mirror of https://github.com/reactos/reactos.git synced 2025-02-23 00:45:24 +00:00
Code Issues Projects Releases Packages Wiki Activity

[NTVDM]

Browse source 
Programs don't expect the XMS function AH = 07h to access the keyboard
controller, since the specification says it's done in a hardware-independent
way. So, reimplement this function by calling EmulatorGetA20() instead.
Also, for the sake of simplicity, use EmulatorSetA20 instead of PCAT_A20Control
to change the A20 state.


svn path=/trunk/; revision=68029
This commit is contained in:
Aleksandar Andrejevic 2015-06-06 02:22:36 +00:00
parent 50f36e7cb3
commit b0c5426a7c
1 changed files with 4 additions and 63 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

67
reactos/subsystems/mvdm/ntvdm/dos/dos32krnl/himem.c
View file

@ -76,47 +76,13 @@ static LONG A20EnableCount = 0;
/* HELPERS FOR A20 LINE *******************************************************/ /* HELPERS FOR A20 LINE *******************************************************/
static BOOLEAN PCAT_A20Control(BYTE Control, PBOOLEAN A20Status)
{
BYTE ControllerOutput;
/* Retrieve PS/2 controller output byte */
IOWriteB(PS2_CONTROL_PORT, 0xD0);
ControllerOutput = IOReadB(PS2_DATA_PORT);
switch (Control)
{
case 0: /* Disable A20 line */
ControllerOutput &= ~0x02;
IOWriteB(PS2_CONTROL_PORT, 0xD1);
IOWriteB(PS2_DATA_PORT, ControllerOutput);
break;
case 1: /* Enable A20 line */
ControllerOutput |= 0x02;
IOWriteB(PS2_CONTROL_PORT, 0xD1);
IOWriteB(PS2_DATA_PORT, ControllerOutput);
break;
default: /* Get A20 status */
break;
}
if (A20Status)
*A20Status = (ControllerOutput & 0x02) != 0;
/* Return success */
return TRUE;
}
static VOID XmsLocalEnableA20(VOID) static VOID XmsLocalEnableA20(VOID)
{ {
/* Enable A20 only if we can do so, otherwise make the caller believe we enabled it */ /* Enable A20 only if we can do so, otherwise make the caller believe we enabled it */
if (!CanChangeA20) goto Quit; if (!CanChangeA20) goto Quit;
/* The count is zero so enable A20 */ /* The count is zero so enable A20 */
if (A20EnableCount == 0 && !PCAT_A20Control(1, NULL)) if (A20EnableCount == 0) EmulatorSetA20(TRUE);
goto Fail;
++A20EnableCount; ++A20EnableCount;
@ -124,11 +90,6 @@ Quit:
setAX(0x0001); /* Line successfully enabled */ setAX(0x0001); /* Line successfully enabled */
setBL(XMS_STATUS_SUCCESS); setBL(XMS_STATUS_SUCCESS);
return; return;
Fail:
setAX(0x0000); /* Line failed to be enabled */
setBL(XMS_STATUS_A20_ERROR);
return;
} }
static VOID XmsLocalDisableA20(VOID) static VOID XmsLocalDisableA20(VOID)
@ -142,8 +103,7 @@ static VOID XmsLocalDisableA20(VOID)
--A20EnableCount; --A20EnableCount;
/* The count is zero so disable A20 */ /* The count is zero so disable A20 */
if (A20EnableCount == 0 && !PCAT_A20Control(0, NULL)) if (A20EnableCount == 0) EmulatorSetA20(FALSE);
goto Fail;
Quit: Quit:
setAX(0x0001); /* Line successfully disabled */ setAX(0x0001); /* Line successfully disabled */
@ -156,25 +116,6 @@ Fail:
return; return;
} }
static VOID XmsGetA20State(VOID)
{
BOOLEAN A20Status = FALSE;
/*
* NOTE: The XMS specification explicitely says that this check is done
* in a hardware-independent manner, by checking whether high memory wraps.
* For our purposes we just call the emulator API.
*/
/* Get A20 status */
if (PCAT_A20Control(2, &A20Status))
setBL(XMS_STATUS_SUCCESS);
else
setBL(XMS_STATUS_A20_ERROR);
setAX(A20Status);
}
/* PRIVATE FUNCTIONS **********************************************************/ /* PRIVATE FUNCTIONS **********************************************************/
static inline PXMS_HANDLE GetHandleRecord(WORD Handle) static inline PXMS_HANDLE GetHandleRecord(WORD Handle)
@ -395,8 +336,8 @@ static VOID WINAPI XmsBopProcedure(LPWORD Stack)
/* Query A20 State */ /* Query A20 State */
case 0x07: case 0x07:
{ {
/* This call sets AX and BL to their correct values */ setAX(EmulatorGetA20());
XmsGetA20State(); setBL(XMS_STATUS_SUCCESS);
break; break;
} }