protected mode initialization

[mike931201]

I'm trying to compile the protected mode initialization example from
the Intel Software Developer's Manual Volume 3A using MASM, but I'm
getting some errors I don't know how to fix.

I put the code at:

http://www.coolgroups.com/asm/pm5.asm

If anyone has tips on how to get it working, I'd appreciate it.

[Intel_Software_Netw1]

Hi Mike,

What errors are you receiving?

(for those following along, the developer manuals are here: http://developer.intel.com/products/processor/manuals/index.htm)

==

Lexi S.

IntelSoftware NetworkSupport

http://www.intel.com/software

Contact us

[mike931201]

MASM doesn't seem to recognize the LGDT instruction.

[Intel_Software_Netw1]

One member of our engineering team suggests that youtry adding this macro toyour file:

LGDT macro mem:req

local x,y

x:

prefetchnt1 mem

y:

org x

byte 0fh

byte 01h

org y

endm

Another member of our engineering team responded as follows:

As of MSVC 2005 in both the 32-bit ml.exe and 64-bit cross-tools ml64.exe, the followingworks just fine when using LGDT... key is to use "FWORD PTR" as operand size modifier and when doing this in 32-bit code, also include ".686P" assembler pseudo-op to enable privileged instructions. Results in same opcode, i.e. 0F 01, being emitted in both 64-bit mode and compatibility/legacy mode. Also, please make sure that section 9.8 of Intel 64 and IA-3 2 Architectures Software Developer's Manual Volume 3A: System Programming Guide and related sections are well understood, as there are implications in order in which steps must be done when altering protected mode operation.

==

Lexi S.

IntelSoftware NetworkSupport

http://www.intel.com/software

Contact us