Display unsigned cnt in spin

dbpage · 2016-09-22 17:11

Do you have an elegant spin method to convert cnt to display unsigned 10 ASCII characters in the range of 0 to 4,294,967,295 without PASM support? It seems easy for someone smarter than me.

kwinn · 2016-09-22 18:06

Take a look at the "Dec" code in the FullDuplexSerial object.

dbpage · 2016-09-22 18:13

FullDuplexSerial "Dec" outputs a signed number in the range of -2,147,483,648 to 2,147,483,647.

Duane Degn · 2016-09-22 18:22

I can't think of a simple way to do this.

I think you need to test to see if the number if negative and if it's negative split the number into to parts.

I can't think of an easy way to split the number to allow you output the 10 characters but I'm sure this is possible.

kwinn · 2016-09-22 18:24

dbpage wrote: »

FullDuplexSerial "Dec" outputs a signed number in the range of -2,147,483,648 to 2,147,483,647.

True, but it is simple to modify the code to print as an unsigned binary number.

dbpage · 2016-09-22 18:27

I'm sure it is simple and I'll be embarrassed for asking the forum to show me how.

Duane Degn · 2016-09-22 18:40

kwinn wrote: »

True, but it is simple to modify the code to print as an unsigned binary number.

Is it? I've modified dec methods a bunch of times but I can't think of a simple way to output an unsigned 32-bit number.

Spin treats all longs as signed numbers.

Ariba · 2016-09-22 18:42

How about this:

  temp := CNT
  ser.dec((temp>>1) / 5)        'show first 9 chars (max.)
  if temp < 0
    temp := POSX-1+temp
  ser.dec(temp // 10)           'show last char

It's not so simple because *, / and // works also with signed numbers. >> allows an unsigned division by 2.

Andy

Edit: There seems to be a Problem with $8000_0000 and $8000_0001 for the lowest digit.

Dave Hein · 2016-09-22 18:59

Ariba, I like your solution. However, if CNT is between 0 and 9 you will get a "0X", where X is the value of CNT. The first ser.dec should be done only if temp < 0 or temp > 9.

ChrisGadd · 2016-09-22 19:52

PUB uDec(value) | i, x, s  
{{
   Transmit the ASCII string equivalent of an un-signed decimal value

   Parameters: value = the numeric value to be transmitted unsigned
   return:     none

   example usage: serial.uDec(-1)

   expected outcome of example usage call: Will print the string "4294967295" to a listening terminal.
}}

  s := 0
  if value < 0
    repeat until value => 0
      value -= 1_000_000_000
      s++

  i := 1_000_000_000

  repeat 10
    if value => i
      fds.Tx(value / i + s~ + "0")
      value //= i
      result~~
    elseif result or i == 1
      fds.Tx("0")
    i /= 10

ersmith · 2016-09-22 20:17

You'll have to adjust the last digit because POSX-1 has a last digit of 6 rather than 0. This should work:

PUB dec_uns(tmp) | last
  if (tmp => 0)
      ser.dec(tmp)
      return
  last := (tmp // 10) + 6
  if (last < 0)
    last += 10
  tmp := (tmp>>1)/5
  ser.dec(tmp)
  ser.dec(last)

(Edited for somewhat cleaner code)

Phil Pilgrim (PhiPi) · 2016-09-22 20:41

ersmith,

I think your method always displays a leading zero.

-Phil

ersmith · 2016-09-22 21:00

Phil Pilgrim (PhiPi) wrote: »

ersmith,

I think your method always displays a leading zero.

-Phil

The first test for "tmp => 0" ensures that any single digit positive numbers will be printed normally. The rest of the code only deals with unsigned numbers that are much greater than 10 (greater than 2 billion, in fact) so "tmp" will always be non-zero after the divide by 10.

Eric

Phil Pilgrim (PhiPi) · 2016-09-22 21:24

I see.

-Phil

dbpage · 2016-09-22 21:47

tmp := (tmp>>1)/5 is elegant. Too bad the last digit is messy.

Good work guys. Thanks.

Ariba · 2016-09-23 01:13

Here is another solution for the last digit:

    tmp := cnt
    if tmp<0 or tmp>9
      ser.dec(tmp>>1 / 5)
    ser.dec(tmp>>1 // 5 * 2 + (tmp & 1))

Andy

Duane Degn · 2016-09-23 02:30

dbpage wrote: »

Good work guys. Thanks.

+1 from me.

I appreciate seeing these solutions.

dbpage · 2016-09-23 02:30

Ariba wrote: »
Here is another solution for the last digit:
    tmp := cnt
    if tmp<0 or tmp>9
      ser.dec(tmp>>1 / 5)
    ser.dec(tmp>>1 // 5 * 2 + (tmp & 1))
Andy

Nice. Elegant.

dbpage · 2016-09-23 14:15

I think

tmp>>1 // 5 << 1 + (tmp & 1)

is a little faster than

tmp>>1 // 5 * 2 + (tmp & 1)

dbpage · 2016-09-23 23:02

While analyzing my last post, I found that, due to differences in operator precedence levels between "<<" and "*", the following snippets give different results:

tmp := -10
tmp>>1 // 5 * 2   ' = 6
tmp>>1 // 5 << 1  ' = 3

By controlling the operator precedence levels, following give identical results:

tmp := -10
tmp>>1 // 5 * 2     ' = 6
(tmp>>1 // 5) << 1  ' = 6

Yet, even though the above snippet results differ, the following give identical results:

tmp := -10
tmp>>1 // 5 << 1 + (tmp & 1)    ' = 6
(tmp>>1 // 5) << 1 + (tmp & 1)  ' = 6

Interesting.

Dave Hein · 2016-09-24 01:09

I get a value of 3 from the expression "tmp>>1 // 5 << 1 + (tmp & 1)" when tmp is -10.

dbpage · 2016-09-24 01:19

You're right. My mistake.

tmp := -10
tmp>>1 // 5 * 2 + (tmp & 1)     ' = 6
(tmp>>1 // 5) << 1 + (tmp & 1)  ' = 6
tmp>>1 // 5 << 1 + (tmp & 1)    ' = 3  Incorrect
(tmp>>1 // 5) << 1 + (tmp & 1)  ' = 6  Correct

Display unsigned cnt in spin

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