Syslinux - Aug 2007 - proper way to sleep

This is not spam about sleep aids :)

Q: Is there a 'standard' way to sleep for a specified number of BIOS
ticks
(or seconds) in a com32 program?

I grepped through the com32 library source and didn't find anything for
'sleep' or 'tick'.

If not, you may want to consider adding:
  void syslinux_sleep(int seconds);
  void syslinux_sleep_bios_ticks(int ticks);


or something like that.

!Gracias!
Miguel

Miguel wrote:
> This is not spam about sleep aids :)
> 
> Q: Is there a 'standard' way to sleep for a specified number of
BIOS ticks
> (or seconds) in a com32 program?
> 
> I grepped through the com32 library source and didn't find anything for
> 'sleep' or 'tick'.
> 
> If not, you may want to consider adding:
>   void syslinux_sleep(int seconds);
>   void syslinux_sleep_bios_ticks(int ticks);
> 
> or something like that.
Not sleep, but there is a standard busy wait, so you could have
something like:

#include <syslinux/idle.h>
#include <sys/times.h>

void syslinux_sleep_ticks(int ticks)
{
	clock_t start = times(NULL);

	while (times(NULL) - start < ticks)
		syslinux_idle();
}

void syslinux_sleep(int seconds)
{
	syslinux_sleep_ticks(seconds*CLK_TCK);
}

> Not sleep, but there is a standard busy wait,
You are correct ... not really sleeping.
> so you could have
> something like:
>
> #include <syslinux/idle.h>
> #include <sys/times.h>
>
> void syslinux_sleep_ticks(int ticks)
> {
> 	clock_t start = times(NULL);
>
> 	while (times(NULL) - start < ticks)
> 		syslinux_idle();
> }
>
> void syslinux_sleep(int seconds)
> {
> 	syslinux_sleep_ticks(seconds*CLK_TCK);
> }
Excellent!


Miguel

Miguel wrote:
> This is not spam about sleep aids :)
>
> Q: Is there a 'standard' way to sleep for a specified number of
BIOS ticks
> (or seconds) in a com32 program?
>
> I grepped through the com32 library source and didn't find anything for
> 'sleep' or 'tick'.
>
> If not, you may want to consider adding:
>   void syslinux_sleep(int seconds);
>   void syslinux_sleep_bios_ticks(int ticks);
>
>   
I had the same problem in my com32 modules.. It could be nice to add a 
sleep(unsigned int msec) function.

Can't we use such code ?

unsigned char sleep(unsigned int msec)
{
   unsigned long micro = 1000*msec;
   com32sys_t inreg,outreg;
   REG_AH(inreg) = 0x86;
   REG_CX(inreg) = (micro >> 16);
   REG_DX(inreg) = (micro & 0xFFFF);
   __intcall(0x15,&inreg,&outreg);
   return REG_AH(outreg);
}

Op 21-08-2007 om 14:47 schreef Miguel:
> hpa wrote:
> > No, please spin on syslinux_idle(), at least for anything other than a
> > trivial delay.  Especially PXELINUX tends to need to perform tasks
while
> > spinning.
> >
> > 	-hpa
> 
> *This* is important information that needs to be more broadly circulated.
I think mentioning it on the syslinux wiki would be a good thing.
( that is one click away on http://syslinux.zytor.com )



Geert Stappers

Miguel wrote:
> hpa wrote:
>> No, please spin on syslinux_idle(), at least for anything other than a
>> trivial delay.  Especially PXELINUX tends to need to perform tasks
while
>> spinning.
>>
>> 	-hpa
> 
> *This* is important information that needs to be more broadly circulated.
> 
Overall the whole API layer needs documentation.

	-hpa