Mail Archives: djgpp/2005/11/24/05:31:51
<blk5743 AT yahoo DOT com DOT tw> wrote in message
news:1132805974 DOT 565960 DOT 317470 AT g14g2000cwa DOT googlegroups DOT com...
> i want to move data between real mode memory and my buffer
> how can i to do this?
>
> i built a structure(Move) to do this
> what pamater should i fill
>
> i got transfer lenght = length
> destinational buff = BYTE databuf[100]
> handle(from AH=0x09)
> phy_addr(from AH=0x0C)
>
> Move.length = length
> Move.SHnd = ?
> Move.Off = ?
> Move.DHnd = ?
> Move.Off = ?
>
> DS = ?
> SI = ?
I'm not sure why you created structure "Move"...
Unlike OpenWATCOM, DJGPP has functions to transfer data between from RM to
PM, and/or from PM to RM. They are called "dosmemget" and "dosmemput",
respectively.
DJGPP also has pre-allocated RM memory called the "transfer buffer" which
can be used to transfer data between RM and PM. The transfer buffer is
designed for to setup the data for RM DOS calls, or get the returned data
from RM DOS calls. The transfer buffer's size varies whether you use
CWSDPMI or PMODEDJ (pmodetsr), but I believe it is about 32k. It's address
is __tb. It's offset is __tb_offset. And, It's segment iis __tb_segment.
Most of this information is in DJGPP's "libc.info".
e.g.,
To transfer RM memory of length "length" from RM "segment:offset" to PM
"buffer", use this:
offset32 = segment * 16 + offset;
dosmemget(int offset32, int length, void *buffer);
e.g.,
To transfer PM memory of length "length" from PM "buffer" to RM
"segment:offset", use this:
offset32 = segment * 16 + offset;
void dosmemput(const void *buffer, int length, int offset);
e.g.,
This function for detecting the LFN API, int 0x21, AX=71a0h could be a
template for using the transfer buffer.
int lfn_71A0(char *mpath) /* used to check if an LFN driver is installed */
{
#ifdef __DJGPP__
dosmemput(mpath, 32, __tb);
r.x.ax = 0x71a0;
r.x.ds = __tb_segment;
r.x.dx = __tb_offset;
r.x.es = r.x.ds;
r.x.di = r.x.dx+OFFS;
r.x.cx = 32;
r.x.flags |= 1;
__dpmi_int(0x21, &r);
dosmemget(__tb+OFFS, 32, mpath);
if (r.x.bx&0x4000)
return(1);
return(0);
#endif
// my OpenWATCOM 1.3. version deleted...
}
Don't reinvent the wheel. :)
Rod Pemberton
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