Memory Mapping problem(win98 p4)

mrchsreddy · 05-13-2008, 09:44 PM

Hi All,
I wrote a simple DOS Program to access my ISA Card using far pointer
My ISA Card have resources like 2 I/O s and 1 Memory
My Card is configured to access the location from D000

My program is working(accessing the device memory) in Pentium 1 and not working in Pentium 4

code for accessing ISA device memory:

unsigned int far* BaseAddr;
BaseAddr = (unsigned int far *)MK_FP(0xD000,0x0000);
in P1 processor (Win98)
IO 1 - OK
IO 2 - OK
Memory - OK

in P4 processor (Win98)
IO 1 - OK
IO 2 - OK
Memory - Not mapping to device

thanks in advance.

**OldGrayGary** · 05-15-2008, 01:07 AM

Hi mrchsreddy

Most likely there are no Win98 drivers for the memory controller on the motherboard for your P4, expecially if it is a dual-core model. Win98 also has timing problems with cpus clocked higher than 2ghz - whether single or multi core.

Best of luck
. . . Gary

05-13-2008, 09:44 PM	#1 (permalink)
mrchsreddy Registered User Join Date: May 2008 Posts: 1 OS: win98,xp,2003	Memory Mapping problem(win98 p4) Hi All, I wrote a simple DOS Program to access my ISA Card using far pointer My ISA Card have resources like 2 I/O s and 1 Memory My Card is configured to access the location from D000 My program is working(accessing the device memory) in Pentium 1 and not working in Pentium 4 code for accessing ISA device memory: unsigned int far* BaseAddr; BaseAddr = (unsigned int far *)MK_FP(0xD000,0x0000); in P1 processor (Win98) IO 1 - OK IO 2 - OK Memory - OK in P4 processor (Win98) IO 1 - OK IO 2 - OK Memory - Not mapping to device thanks in advance.

05-15-2008, 01:07 AM	#2 (permalink)
OldGrayGary Mentor, Microsoft Support Join Date: Jun 2006 Location: Woodland Hills, CA Posts: 1,978 OS: Windows 98se/2000/XP/Vista	Re: Memory Mapping problem(win98 p4) Hi mrchsreddy Most likely there are no Win98 drivers for the memory controller on the motherboard for your P4, expecially if it is a dual-core model. Win98 also has timing problems with cpus clocked higher than 2ghz - whether single or multi core. Best of luck . . . Gary __________________