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From:	"Andrew Fairburn" <a DOT j DOT fairburn AT durham DOT ac DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Allocating memory....
Date:	Thu, 21 Feb 2002 14:59:06 -0000
Organization:	University of Durham, Durham, UK
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ive been trying to allocate a piece of memory so that both teh host itself
and a pci device reading straight from memory can acces it. Obviously its
not to hard to do this from the host point of view, but i need the real
address of the memory segment and offsets, not virtual, to access it via teh
pci device. At first i was attempting to use the
__dpmi_allocate_linear_memory()  function to get the real addres, then used
a descriptor to get the virtual address for teh host acces.
i.e.

smi.size = 0xfff;            // allocates size of host memory
if ((__dpmi_allocate_linear_memory(&smi, 1)) == -1) {
 printf("out");
 exit(32);
 }
sysaddr = smi.address;           // sets sysaddr to the start of smi memory
sys_sel = __dpmi_allocate_ldt_descriptors (2);  //allocates sys_sel as a
descriptor
__dpmi_set_segment_base_address (sys_sel, smi.address); // sets the base
address of the host memory segment
__dpmi_set_segment_limit (sys_sel, smi.size - 1);       // sets the size of
the host memory segment

Unfortunately i found out this call isnt supported by the windows or cws
dpmi library......

Is there any other way of doing this and/or a way of making this call work??

Thanks for any help,

Andy.

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