The simFlight Network Forums

# Off Topic,Epicinfo question

## Recommended Posts

Hi Pete i'm driving crazy with this,maybe you can help,i am introducing a modification in my epl code,and i don't remember too much about epic ISA programming

The point is that I need to check when the aircraft bank is more than 25 degrees,to the left and to the right.

To do this i want to use the PH 13 (PLANE_BANK_DEGREES) that it says that the first two bytes ( 0 and 1 )are for the absolute value and the the others ( 2 and 3 ) are used to determine the negative value (bank to the left I guess )

I just want to put the value in a variable for check if it is at more than +25 o more than -25 but I have no idea how to do it.

Any sugestion ?

thanks Pete

##### Share on other sites

Hi Pete i'm driving crazy with this,maybe you can help,i am introducing a modification in my epl code,and i don't remember too much about epic ISA programming

Nor me!

I just want to put the value in a variable for check if it is at more than +25 of more than -25 but I have no idea how to do it.

A peek at some typical lines in a Log would help. But I think to detect negative you just need to check the top bit (0x8000) in the 16-bit value from bytes 2-3 (or the 0x80 bit in byte 3). To do you could either use AND or TEST (if those instructions are supported -- see I just don't remember!) or, considering EPL doesn't have negative numbers, see if the 16-bit value is greater than 32767 (0x7FFF) or the high byte greater than 127 (0x7F).

Or do the whole job in reverse by testing if the 16-bit value is either Less than 25 (i.e. 0 - 24) or between 32768 and 32793 (representing -1 to -24).

Regards

Pete

##### Share on other sites

Nor me!

:mrgreen:

A peek at some typical lines in a Log would help. But I think to detect negative you just need to check the top bit (0x8000) in the 16-bit value from bytes 2-3 (or the 0x80 bit in byte 3). To do you could either use AND or TEST (if those instructions are supported -- see I just don't remember!) or, considering EPL doesn't have negative numbers, see if the 16-bit value is greater than 32767 (0x7FFF) or the high byte greater than 127 (0x7F).

Or do the whole job in reverse by testing if the 16-bit value is either Less than 25 (i.e. 0 - 24) or between 32768 and 32793 (representing -1 to -24).

Regards

Pete

Thanks for the help,i will check it

May I check for " greather than 27" at byte 3 to get the negative ?

##### Share on other sites

May I check for " greather than 27" at byte 3 to get the negative ?

127 not 27, yes.

Pete

## Create an account

Register a new account