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Index > Windows > How to print a float value?

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MikeHart



Joined: 31 May 2005
Posts: 7
MikeHart
Hi all,

I try to get this to work:

Code:
format PE CONSOLE 4.0
entry start

Include 'win32a.inc'

section ".code" code readable writeable executable

        string   db "Float value:",0
        szEnv    db "%s %4.2f",0
        valu     dq 6.6

start:
        cinvoke printf,szEnv, string, dword [valu]
        cinvoke getchar
        invoke ExitProcess,0

section '.idata' import data readable writeable

  library kernel32,'kernel32.dll',\
          msvcrt,'msvcrt.dll'

  import kernel32,\
         ExitProcess,'ExitProcess'

  import msvcrt,\
         getchar,'getchar',\
         printf,'printf'                               


As you can see, it doesn't print 6.6 on the console. What mistake did I do?

Cheers
Michael
Post 30 Jun 2005, 15:44
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Tommy



Joined: 17 Jun 2003
Posts: 489
Location: Norway
Tommy
change dq 6.6 (qword) to dd 6.6 (dword)
Post 30 Jun 2005, 16:31
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MikeHart



Joined: 31 May 2005
Posts: 7
MikeHart
Nope, that didn't help, still get that huge number that has nothing to do with 6.6
Post 30 Jun 2005, 18:11
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Tomasz Grysztar



Joined: 16 Jun 2003
Posts: 7796
Location: Kraków, Poland
Tomasz Grysztar
It should be qword, but you didn't pass the whole quad word to the "printf", only the lower half. To pass the whole quad word, do it like:
Code:
        cinvoke printf,szEnv, string, dword [valu], dword [valu+4]    
Post 30 Jun 2005, 18:14
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MikeHart



Joined: 31 May 2005
Posts: 7
MikeHart
Thanks Tomasz very much. That worked. I have to learn a lot but I wanna thank you for building such a great assembler!!!

Michael Hartlef
Post 30 Jun 2005, 18:25
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MikeHart



Joined: 31 May 2005
Posts: 7
MikeHart
Ok, how do I display a float value that is stored inside EAX?

Code:
format PE CONSOLE 4.0
entry start 

Include 'win32a.inc' 

section ".code" code readable writeable executable 

        string   db "Float value:",0 
        szEnv    db "%s %4.2f",13,10,0
        valu     dq 6.6 

start: 
        cinvoke printf,szEnv, string, dword [valu], dword [valu+4]
        mov eax , dword [valu]
        cinvoke printf,szEnv, string, eax

        cinvoke getchar 
        invoke ExitProcess,0 

section '.idata' import data readable writeable 

  library kernel32,'kernel32.dll',\ 
          msvcrt,'msvcrt.dll' 

  import kernel32,\ 
         ExitProcess,'ExitProcess' 

  import msvcrt,\ 
         getchar,'getchar',\ 
         printf,'printf'    
Post 24 Dec 2006, 19:50
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gunblade



Joined: 19 Feb 2004
Posts: 209
gunblade
You'll have to use 2 registers:

Code:
mov eax , dword [valu]
mov ebx, dword [valu+4]
cinvoke printf,szEnv, string, eax, ebx    


Otherwise you have the same problem as before, where you were only passing 4 of the 8 bytes in the quadword.
Post 25 Dec 2006, 11:39
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MikeHart



Joined: 31 May 2005
Posts: 7
MikeHart
Thank you gunblade and merry chrismas to you!
Post 25 Dec 2006, 17:39
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Garthower



Joined: 21 Apr 2006
Posts: 158
Location: Ukraine
Garthower
And how about manual converting float number to string? Somebody has examples? Or ideas? Smile
Post 07 Feb 2007, 20:51
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vid
Verbosity in development


Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia
vid
tomasz told to work on it for FASMLIB .... no idea how far it is
Post 07 Feb 2007, 21:26
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cod3b453



Joined: 25 Aug 2004
Posts: 619
cod3b453
Garthower wrote:
And how about manual converting float number to string? Somebody has examples? Or ideas?

This is something I'm still trying to finish, but it goes like this:
(If anything looks wrong please tell me Very Happy)
Code:
;Let D = double (qword)
;
;1) Is D < 0 ? Yes: bMinus = True
;2) D = |D| (Abs)
;3) E10 = Floor(Log10(D))
;4) Is E10 < 0: Yes: bEMinus = True
;5) P10 = 10 ^ -E10
;6) E10 = |E10| (Abs)
;7) D2 = D × P10 (Exponent = 0)
;Cool rbx = D2
;9) rbx --> dst ASCII

fstp qword [value] ;-Part 8
mov rbx,[value]    ;/
mov rsi,[Dst]

@@:

mov rax,rbx
mov rcx,0x199999999999999A
mul rcx
; rdx = rax / 10
mov rax,rbx ; restore rax
mov ebx,rdx ; Required for loop
mov rcx,rdx

shl rcx,1   ;\
shl rdx,3   ; rdx = rdx * 10
add rdx,rcx ;/
sub rax,rdx ; rax = last decimal digit value

add al,'0'  ; ASCII digit base
mov [rsi],al

inc rsi

jif rbx,ne,0,@b ; Done?
; Swap digits back
mov rax,rsi
mov rdi,[dst]
sub rax,rdi
mov rcx,rax
shr rax,1
dec rcx

@@:

dec rsi

mov dh,[rsi]
mov dl,[rdi]
mov [rsi],dl
mov [rdi],dh

inc rdi
dec rax

jif rax,ne,0,@b

;10) Subtract rcx from E10
;11) Do same as 8 & 9 for E10 into dstE
;12) If bMinus = True print "-"
;    print dst
;    print "E"
;    If bEMinus = True print "-"
;    print dstE
    


Maybe I should try finishing it and let a 64bitter try it Cool
Post 07 Feb 2007, 21:56
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Reverend



Joined: 24 Aug 2004
Posts: 408
Location: Poland
Reverend
http://board.flatassembler.net/topic.php?t=4377&start=53
There are my converting routines. Just convert float value and save it as a string in buffer, then display it.
Post 08 Feb 2007, 20:26
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