PNut/Spin2 Latest Version (v51 - New POW, LOG2, EXP2, LOG10, EXP10, LOG, EXP floating-point ops)

Francis Bauer · 2025-02-28 07:27

@wummi said:
Hi Chip,
I found a strange behavior with REPEAT <count> WITH <variable> when count is zero.
PUB go () | i
  repeat 0 with i
    debug(sdec(i))
{ debug output
Cog0  i = 0
Cog0  i = -1
}
I expected debug(sdec(i)) is never executed, but it executes twice.

I believe this behavior is expected. The Spin document indicates that the count value is normally expected to be a number greater than 0.
The WITH form of the REPEAT statement is a smaller/faster version than the REPEAT FROM statement.

v40 2023-09-21 ● New smaller/faster REPEAT form added for iterating a variable from 0 to n-1, where n > 0.
   REPEAT n WITH i 'best way to iterate a variable from 0 to n - 1
   REPEAT i from 0 to n - 1 'general equivalent, though WITH needs n > 0

Example:

_clkfreq = 200_000_000

PUB go () | i,n

  repeat 0 with i
    debug("with loop: ",sdec(i))

  n := 0  
  repeat i from 0 to n-1
    debug("from loop: ",sdec(i))

Output:
Cog0  with loop: i = 0                                                          
Cog0  with loop: i = -1                                                         
Cog0  from loop: i = 0                                                          
Cog0  from loop: i = -1

wummi · 2025-02-28 09:49

OK, i do not now that n must be greater than 0

evanh · 2025-02-28 11:15

Undefined is not the same as expected.

cgracey · 2025-04-02 21:29

A new PNut_v51 has been posted at the top of this thread.

v51 - 2025.04.02 - New POW, LOG2, EXP2, LOG10, EXP10, LOG, and EXP floating-point operators. SIZEOF() can now be used by PASM code to get sizes of structures. Long variables within structures can now be used as method pointers. Ignore-multiple-return-values '_ (number_of_longs)' had a stack bug rendering it useless, so it has been fixed and the syntax has been changed to use brackets, instead: '_ [number_of_longs]'.

RbtsEvrywhr_Riley · 2025-05-22 00:45

Posted this to the github but I'm not sure if it goes there or here, having some syntax issues with structs vs the example.

https://github.com/parallaxinc/P2_PNut_Public/issues/6

Hope I didn't miss a post about it or something. lil help?

ersmith · 2025-05-22 09:03

Make sure your code has a {Spin2_v51} comment at the very start to declare the Spin2 version number.

In your posted example you've got syntax like:

STRUCT mavlink_message_header(BYTE mark = PROTOCOL_MARKER_V1, BYTE mlen, BYTE seq, BYTE srcSystem, BYTE srcComponent, BYTE msgId)

I don't think initializing the structure members (mark = xxx) is legal in PNut; it certainly isn't in FlexSpin.

RbtsEvrywhr_Riley · 2025-05-22 16:40

Thanks. I'd like to suggest this be made more prominent in the manual than just in a changelog note 10 versions back from current. This is extremely easy to miss if you don't know what you're looking for.

PNut/Spin2 Latest Version (v51 - New POW, LOG2, EXP2, LOG10, EXP10, LOG, EXP floating-point ops)

Comments