[Proj] Re: Re: Proj4 Bug (rtodms)
cp
ch.panel at free.fr
Wed Nov 8 12:10:09 EST 2006
After these rights observations, I look at more seriously this portion of
code.
The numbers have effectively right and exact representations in ten-bytes
format, but the compiler instead of making r/60 makes r * 1/60 so it changes
a little thing. I precise that this is done without any optimization (force
no optimization) and with option "don't correct FDIV flaw" (for old
processors) and "no quick floating points". I have seen some quircks in
MS-Compiler, now I am seeing in Borland compiler.
It is not possible to go through and to force the compiler (I don't know how
?) to generate fdiv instead of fmul instruction.
here is the code generated
;
; res1 = (int)(r / 60.);
;
?debug L 11
fld tbyte ptr [@2] <= 1/60 with 8
bytes precision and not 10 bytes precision
fmul qword ptr [ebp-8]
call __ftol
mov dword ptr [_res1],eax
;
; res2 = floor(r / 60.);
;
?debug L 12
fld tbyte ptr [@2]
fmul qword ptr [ebp-8]
add esp,-8
fstp qword ptr [esp]
call _floor
add esp,8
call __ftol
mov dword ptr [_res2],eax
;
; printf("%s",(res1==res2) ? "OK!" : "NOT OK!");
A different code is generated by MS-Compiler which is right in this case.
A same Code is generated with the free command line compiler BCC32.exe :
Borland C++ 5.5.1 (Borland Builder, disabling too all optimizations)
So the problem is staying for all people who are working with Borland
environment or with code optimization and r / 60. give a false result.
In Last, thanks for all constructors of proj4 and BRAVO for the work
accomplished.
C.PANEL
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