From: "Martin Czamai" <M DOT Czamai AT peak-system DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Does CWSDPMI block jumps to 0xFFFF0 ??
Date: Sat, 20 Oct 2001 15:45:40 +0200
Organization: [neXgo] the next generation online
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Hi,

can anybody tell me whether cwsdpmi blocks jumps to 0xFFFF0 (0xFFFF :
0x0000) to reboot the computer??
If not, what's wrong at this few lines of code??

#include <sys/farptr.h>
#include <go32.h>

void (*pRstFunction)(void);                                     // simple
function pointer

int main(void)
{
     _farpokew(_dos_ds, 0x40*16+0x72, 0x1234);  // seg*16 +offset ; warm
boot
//   _farpokew(_dos_ds, 0x40*16+0x72, 0x0000);  // cold boot
//   jmp to Adr. 0xFFFF:0000

//   __asm__(" jmp 0xFFFF0 ");           // direct jump to adress causes
segment violation (but a jmp to 0xFFFF works fine..)

     pRstFunction = 0xFFFF0;                // correct pointer
     (*pRstFunction)();                            // perform jump; causes
just a segement violation instead of a reboot
     return(0);                                          // should never run
this line of code, just to make the compiler happy
}

Thanks in advance for any help

Martin
M DOT Czamai AT PEAK-System DOT com