Moving/Seperating numbers

JBWolf · 2013-02-17 02:02

I believe there are some unique ways using SPIN to move bytes and numbers around and was hoping somone could provide some help.
I am compiling multiple variables into one numeric value by multiplying by 10 and adding the next variable.
i.e... AllVars := ((((VarA * 10) + VarB) * 10) + VarC)
None of these individual variables exceed a value of 9 so they can be compiled.

So now I'm trying to find the best way to return it back to multiple variables.

I can only think of a complicated way to do this and the numbers do have remainders which I expect to be lost since the variables are not declared as float.
i.e:
VarA := (AllVars / 100)
VarB := ((AllVars / 10) - (VarA * 10))
VarC := ((AllVars - (VarA * 100)) - (VarB * 10))

I was wondering if there is SPIN code to simplify this task.
Thanks

kuroneko · 2013-02-17 03:39

Try this, it splits the number into its decimal digits, each being stored into an element of the digits byte array. Sign is currently ignored but can easily be added.

CON
  _clkmode = XTAL1|PLL16X
  _xinfreq = 5_000_000

OBJ
  serial: "FullDuplexSerial"
  
VAR
  byte  digits[16]
  
PUB null | n

  serial.start(31, 30, %0000, 115200)
  waitcnt(clkfreq*3 + cnt)
  serial.tx(0)
  
  n := split(123456789)

  repeat n
    serial.dec(digits[--n])
  serial.tx(13)

PRI split(value) : n

' n starts as 0

  repeat
    digits[n++] := ||(value // 10)
    value /= 10
  while value

' fill level is returned

DAT

MagIO2 · 2013-02-17 03:43

Fastest way is using BCD representation. It makes use of the fact that the numbers 0 - 9 are equal to %0000 - %1001 and need maximum 4 bits

AllVars := VarA | VarB<<4 | VarC<<8

The reverse operation is:
VarA := AllVars & %1111
VarB := AllVars>>4 & %1111
VarC := AllVars>>8 & %1111

Moving/Seperating numbers

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