How to display large numbers

[paul borgmeier]

Opps - on the comment in the above code snippet ....

is:
' take 4*65536+55296 = 4*(65000+536)+55296 = 4*65000+4*536+55296
' the 4*65000 term does not contribute to the low 3 digits so leave it out

was:
' take 4*65536+55296 = 4*(6200+536)+55296 = 4*62000+4*536+55296
' the 4*62000 term does not contribute to the low 3 digits so leave it out


I need more coffee - paul

[BigWumpus]

OK,

32-bit-arithemtik,
sometimes I'm happy to have learned the basics of our job (on a pdp/8 with 12-bit-words an silly switches and lamps on the front).

Div-by-10 ... uuuh ... I feel sleepy!

$7FFFFFFF is decimal 2147483647 .... uuuh, the big one !

I think, you will deal with 7-count numbers....
Just look, if the number is bigger then 999999:

Flag=0
if High_Word>$F Then Flag=1
if High_Word=$F AND Low_Word>$423F Then Flag=1

If it is bigger, count how often by subtracting 1000000 !

Ct=0
If Flag Then
Repeat
If Low_Word<$4240 Then High_Word=High_Word-1
Low_Word=Low_Word-$4240:Ct=Ct+1
[...] copy **** from above
Until Flag=0
Endif

You got an digit ! Just Store or print it ! (LCDWRITE "0"+Ct)
Multiply the rest by 10 !

Gosub Rotate32 (x2)
High_Copy=High_Byte:Low_Copy=Low_Byte
Gosub Rotate32:Gosub Rotate32 (all together x8)
High_Word=High_Word+High_Copy
If Low_Word.15 AND Low_Copy.15 Then High_Word=High_Word+1:Low_Word.15=0:Low_Copy.15=0
Flag=Low_Word.15 or Low_Copy.15
Low_Word=Low_Word+Low_Copy:If Flag AND (Low_Word.15=0) Then High_Word=High_Word+1

Rotate32:
High_Word=High_Word<<1:If Low_Word.15 Then High_Word.0=1
Low_Word=Low_Word<<1:Return

uuuuh ... with assembler its much smoother because of the carry-flag.


Repeat it seven times !
Go sleep!