Want to get the correct negative number , Please help

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RonsWare

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Posted: 20th Apr 2012 15:40

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Hello all fellow coders.
I have a problem the variable types of DarkBasic Proffesional.

I need to get the next negative result -512

0x00FE after turning 0xFE00

In the HEX Editor i use i get this :

00 as Shortint: 0
00FE as Word: 65024
00FE as Integer: -512

The integer is correct

The next value is done correct.

In the Hex Editor.

60 as Shortint: 96
6000 as Word: 96
6000 as Integer: 96

0x6000 after turning 0x0060

It gives the correct number of 96

I just can't get the negative number of -512
I have tried everything i can think off.

Any help will be greatly appreciated.

I have included some code.

Thanks Ron.

nr as integer
nr2 as integer

nr = 0xFE00 ` This must -512 !!
nr2 = 0x0060 ` This is correct 96

print nr
print nr2

do
loop
end

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RonsWare

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Posted: 20th Apr 2012 15:47

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Here is the code.

+ Code Snippet

nr   as integer
nr2  as integer

nr  = 0xFE00 ` This must -512     !!
nr2 = 0x0060 ` This is correct 96

print nr
print nr2

do
loop
end

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zeroSlave

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Posted: 20th Apr 2012 23:02

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+ Code Snippet


nr   as integer
nr2  as integer
inr as integer
inr2 as integer

nr  = -0x200 ` This must -512     !!
nr2 = 0x0060 ` This is correct 96
inr = -512
inr2 = 96


print nr
print nr2

print inr
print inr2

do
loop
end

Would't this work? I'm not exactly sure why you are using hex so i'm not really sure what you are looking for.

Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.

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WLGfx

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Posted: 21st Apr 2012 03:36 Edited at: 21st Apr 2012 03:40

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An integer in DBP is a signed four byte integer so were you're declaring it as 0xFE00 (a short word value by the look) it should be something like 0xFFFFFE00.

EDIT: In DBP you can read a WORD value from a file and then cast it to an integer.

EDIT2: Although it does look like you cannot have a signed WORD...

Quote: "INTEGER Range : –2,147,483,648 to 2,147,483,647
REAL Range : 3.4E +/- 38 (7 digits)
BOOLEAN Range : 0 to 1
BYTE Range : 0 to 255
WORD Range : 0 to 65535
DWORD Range : 0 to 4,294,967,295
DOUBLE INTEGER Range : –9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
DOUBLE FLOAT Range : 1.7E +/- 308 (15 digits)
"

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Warning! May contain Nuts!

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RonsWare

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Posted: 21st Apr 2012 08:10

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zeroSlave and WLGfx thanks.

I am creating a map editor voor de good old doom games.
For me it's just to learn how ID software created IWAD and PWAD
directory structure.
IWAD = Internal WAD
PWAD = Patch WAD
WAD = Where's All the Data

The numbers are coord's (x,y)

I made a PWAD file myself to analyse.
Thats is why iám using the HEX Editor.
To check the data stored in the PWAD file

To read the coord data from the file i can't use the unsigned word.
Like WLGfx shows it's a positive variable. (0-65535)
it the only variable that is 16 bits.

x coord = 2 bytes and the y coord = 2 bytes.

I can't use the integer because it's 32 bits.

What i realy need is a signed integer.
but then one that is 16 bits.

Or a way to convert the number so it is giving me the correct -512.

if you have any questions please do.

Thanks Ron.

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WLGfx

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Posted: 21st Apr 2012 15:20

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A bit of psuedo code, but it's an idea of casting a WORD to an integer:

+ Code Snippet

inWord as WORD
outInt as integer

if ( inWord and 0x8000 ) then outInt = inWord or 0xffff0000 else outInt = inWord

Fingers crossed that'll fix the casting...

Mental arithmetic? Me? (That's for computers) I can't subtract a fart from a plate of beans!
Warning! May contain Nuts!

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RonsWare

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Posted: 21st Apr 2012 17:17

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WLGfx you are the best

Thank's to you i have created a function with your code.

You helped me a lot thank's

Cheers Ron.

+ Code Snippet

`Thanks to WLGfx this function is written.

global outint as integer

x1  = 0xfe00   ` -512     First x,y coord.
y1  = 0x0060   `   96
x2  = 0xffe0   `  -32     Second x,y coord.
y2  = 0x0060   `   96

MakeInt16( x1 )
x1 = outint

MakeInt16( y1 )
y1 = outint

MakeInt16( x2 )
x2 = outint

MakeInt16( y2 )
y2 = outint

print x1
print y1
print x2
print y2


do
loop
end

function MakeInt16( inword as word )
if (inword and 0x8000)
    outint = inword or 0xffff0000
else
    outint=inword
endif
endfunction

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RonsWare

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Posted: 21st Apr 2012 17:42

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I have posted the function code on the codebase also.
I hope that it will be off good use for people.

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RonsWare

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Posted: 21st Apr 2012 17:56

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Here is the code that make it clear what i wanted to do.

+ Code Snippet

`Thanks to WLGfx this function is written.

global outint as integer

x1  = 0xfe00   ` -512     First x,y coord.
y1  = 0x0060   `   96
x2  = 0xffe0   `  -32     Second x,y coord.
y2  = 0x0060   `   96

print "Before (all value's are positive)."
print "This is wrong !"
print
print x1       ` Before.
print y1
print x2
print y2
print

MakeInt16( x1 )
x1 = outint

MakeInt16( y1 )
y1 = outint

MakeInt16( x2 )
x2 = outint

MakeInt16( y2 )
y2 = outint

print "After converting."
print "Now they are correct !"
print
print x1       ` After.
print y1
print x2
print y2


do
loop
end

function MakeInt16( inword as word )
if (inword and 0x8000)
    outint = inword or 0xffff0000
else
    outint=inword
endif
endfunction

Cheers Ron

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WLGfx

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Posted: 21st Apr 2012 18:05 Edited at: 21st Apr 2012 18:14

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The function could be easier like this:

+ Code Snippet

function MakeInt16( inWord as WORD )
    local outInt as integer
    if ( inWord and 0x8000 )
        outInt = inWord or 0xffff0000
    else
        outInt = inWord
    endif
endfunction outInt

rem use as: myInt = MakeInt16( inWordValue )

No probs RonsWare and have a beer for me too...

Mental arithmetic? Me? (That's for computers) I can't subtract a fart from a plate of beans!
Warning! May contain Nuts!

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RonsWare

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Posted: 21st Apr 2012 18:50

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Your are right

I put the line in the code.

Thank's again WLGfx.

Cheers Ron.

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