| |
JackAsser
Registered: Jun 2002
Posts: 1989 |
32bit Decimal convertion
Anybody got this shitz for 32-bit numbers? http://codebase64.org/doku.php?id=base:hexadecimal_to_decimal_c.. |
|
... 17 posts hidden. Click here to view all posts....
|
| |
JackAsser
Registered: Jun 2002
Posts: 1989 |
Or I just show the experience points in hex... ;) |
| |
JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: If he is, I could sort of sympathise with that, if it was part of a large project like Eye of the Beholder with zillions of lines of code and someone else had already implemented a 32-bit version of that routine.
I can't sympathise with the spelling of "Convertion" (Conversion) though. ;)
Also not zillions, but just 40688 at the moment (675kb). |
| |
Krill
Registered: Apr 2002
Posts: 2851 |
Quoting JackAssernope, same there as on Codebase. Indeed, Codebase has a straight 1:1 rip of the original 6502.org page, without giving proper credit. Not cool, Codebase, not cool.
Quoting JackAsserThinking of some simple shift+add with the 1/10 since that is a very simple bitpattern 110011001100110011... Please elaborate. :) |
| |
JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: You're too lazy to pick any of the 3 approaches and modify the routine for 32-bit numbers? :)
Actually I didn't even bother to look closer on that code posted there but I didn't now and it's meant to be extended.
"The principle should be pretty clear. You can take it out to as many digits as you want."
However it relies on decimal mode being set, something my interrupt handlers can't handle and I'm not willing to fuck timing all over the place. |
| |
Krill
Registered: Apr 2002
Posts: 2851 |
You have shitloads of spare memory for lookup tables, right? :) That allows for a very simple and fast approach with 4 8-bit lookups and 3 adds, both times decimal places, or something, i think. |
| |
JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: Quoting JackAssernope, same there as on Codebase. Indeed, Codebase has a straight 1:1 rip of the original 6502.org page, without giving proper credit. Not cool, Codebase, not cool.
Quoting JackAsserThinking of some simple shift+add with the 1/10 since that is a very simple bitpattern 110011001100110011... Please elaborate. :)
Basically you want to do:
int value = 0xdeadbeef;
int digit0 = value%10; value/=10;
int digit1 = value%10; value/=10;
int digit2 = value%10; value/=10;
int digit3 = value%10; value/=10;
int digit4 = value%10; value/=10;
int digit5 = value%10; value/=10;
.
.
.
When rolling your own division the remainder will pop out automatically. Doing a /10 is the same as doing a multiply by 1/10. Multiply by 1/10 is simply a shift+add multiplication with a %110011001100... bitpattern. |
| |
JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: You have shitloads of spare memory for lookup tables, right? :) That allows for a very simple and fast approach with 4 8-bit lookups and 3 adds, both times decimal places, or something, i think.
I actually don't have shitloads of memory left and this code can be dead slow so I'd rather have it tight. |
| |
Krill
Registered: Apr 2002
Posts: 2851 |
Then i'd go with the first algorithm, bitwise conversion without any tables or div/mul. |
| |
JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: Then i'd go with the first algorithm, bitwise conversion without any tables or div/mul.
Need to digest it. Don't understand at all how it works atm. :D |
| |
JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: Need to digest it. Don't understand at all how it works atm. :D
Or I just substract billions, and when underflowing, roll back one step and start substracting 100-millions, and then 10-millions etc.. down to ones. Should be resonably fast.
ldx #<-1
:
sec
lda TMP+0
sbc #<(1000000000>>0)
sta TMP+0
lda TMP+1
sbc #<(1000000000>>8)
sta TMP+1
lda TMP+2
sbc #<(1000000000>>16)
sta TMP+2
lda TMP+1
sbc #<(1000000000>>24)
sta TMP+1
inx
bvc :-
etc.. |
| Previous - 1 | 2 | 3 | 4 - Next |
