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New Re: Also 12 on HPQ Presario 5831 (500 MHz Athlon)/gcc 2.95.4
OK, then, it's gcc (why am I not surprised?)

The 10 was reported by C++Builder, which uses the FPU natively.
jb4
"There are two ways for you to have lower Prescription-drug costs. One is you could hire Rush Limbaugh's housekeeper ... or you can elect me President."
John Kerry
New Re: Also 12 on HPQ Presario 5831 (500 MHz Athlon)/gcc 2.95.4
Come on jb, you know the gcc math library is using the FPU.

It's just tracking round error internally to the library when needed:
\n\n\n[voyager] drossl 1: ~> vi junk.c\n\n#include <math.h>\n\nvoid main(void)\n{\n   float a, x = 1.0;\n   double b, y = 1.0;\n   long double c, z = 1.0;\n\n   a = atan(x);\n   b = atan(y);\n   c = atan(z);\n\n   c = (long double) a + (long double) b;\n}\n\n[voyager] drossl 2: ~> gcc -S -O0 junk.c\njunk.c: In function `main':\njunk.c:4: warning: return type of `main' is not `int'\n[voyager] drossl 3: ~> vi junk.s\n\n        .file   "junk.c"\n        .text\n.globl main\n        .type   main, @function\nmain:\n\n;       Set up\n\n        pushl   %ebp\n        movl    %esp, %ebp\n        subl    $88, %esp\n        andl    $-16, %esp\n        movl    $0, %eax\n        subl    %eax, %esp\n        movl    $0x3f800000, -16(%ebp)\n        movl    $0, -32(%ebp)\n        movl    $1072693248, -28(%ebp)\n        movl    $0, -72(%ebp)\n        movl    $-2147483648, -68(%ebp)\n        movl    $16383, -64(%ebp)\n\n;       float call to atan\n\n        subl    $8, %esp\n        flds    -16(%ebp)\n        leal    -8(%esp), %esp\n        fstpl   (%esp)\n        call    atan\n\n;       double call to atan\n\n        addl    $16, %esp\n        fstps   -12(%ebp)\n        subl    $8, %esp\n        pushl   -28(%ebp)\n        pushl   -32(%ebp)\n        call    atan\n\n;       long double call to atan\n\n        addl    $16, %esp\n        fstpl   -24(%ebp)\n        subl    $8, %esp\n        fldt    -72(%ebp)\n        fstpl   -88(%ebp)\n        movl    -88(%ebp), %eax\n        movl    -84(%ebp), %edx\n        pushl   %edx\n        pushl   %eax\n        call    atan\n\n;       long double arithmetic\n\n        addl    $16, %esp\n        fstpt   -56(%ebp)\n        flds    -12(%ebp)\n        fldl    -24(%ebp)\n        faddp   %st, %st(1)\n        fstpt   -56(%ebp)\n\n        leave\n        ret\n        .size   main, .-main\n        .ident  "GCC: (GNU) 3.3 20030226 (prerelease) (SuSE Linux)"\n\n\n


-drl
New Sorry Ross: No Sale
Yer not gonna convince me using that garbage that passes for assembler that gcrapcrap spews! How the fuck do I know what an 'fstpl' or 'flds' or 'fstps' really maps to? The back-end could just as easily map it to an invalid instruction opcode that invokes the FPE (and quite probably does!).

Nope...show me real assembler code, and then I'll be convinced. I wanna know exactly what opcode causes the FPU to kick into (the heretofore undocumented) 128-bit mode....
jb4
"There are two ways for you to have lower Prescription-drug costs. One is you could hire Rush Limbaugh's housekeeper ... or you can elect me President."
John Kerry
New Re: Sorry Ross: No Sale
You're a hard man jb, to make me search a cvsweb on a phone line...

glibc-2.3.2 inverse cosine, single:
[link|http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/sysdeps/i386/fpu/e_acosf.S?rev=1.1&content-type=text/x-cvsweb-markup&cvsroot=glibc|http://sources.redha...kup&cvsroot=glibc]

glibc-2.3.2 inverse cosine, long double:
[link|http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/sysdeps/i386/fpu/e_acosl.c?rev=1.1&content-type=text/x-cvsweb-markup&cvsroot=glibc|http://sources.redha...kup&cvsroot=glibc]

The whole IEEE interface:
[link|http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/sysdeps/i386/fpu/?cvsroot=glibc|http://sources.redha...pu/?cvsroot=glibc]

This is interesting:
[link|http://www.ussg.iu.edu/hypermail/linux/kernel/0103.0/0453.html|http://www.ussg.iu.e.../0103.0/0453.html]

(drill down down down)

What Linux does presently on x86 is as right as right can be on this platform. Compare with what MS's compilers do (die when you run out of the fp stack slots, telling users to simplify the expressions in the source code) and be happy. The *BSD choice is valid by some lines of thought, but it also denies people the happy accident of computing with more precision and range than they thought they needed. Overall, computing with x86 double-extended is a good thing so long as you don't introduce multiple roundings. That's a compiler issue, not a kernel one. Historical note: According to one of the x87 designers, this all boils down to the simple fact that there's no time when a pair of collaborators in California and Israel can be both awake and lucid enough to explain things well over a noisy telephone line. Amazing that it really wasn't long ago. And if anyone's really interested, keep checking

[link|http://www.cs.berkeley.edu/~wkahan/|http://www.cs.berkeley.edu/~wkahan/]

as some of Dr. Kahan's older papers are slowly converted and added. They give a great deal of insight into the choices that eventually became the accepted IEEE 754 standard.
-drl
New Please stand by...
...This is an acknowledgement of your outstanding work in tracking down those links. There is something...er, odd...about them, and I have to do a little looking up which I haven't got time to do now here at work.

Watch this space for an update soon...
jb4
"There are two ways for you to have lower Prescription-drug costs. One is you could hire Rush Limbaugh's housekeeper ... or you can elect me President."
John Kerry
New Doesn't compile here
peter@cordelia:~> gcc junk.c
junk.c: In function `main':
junk.c:4: warning: return type of `main' is not `int'
/tmp/ccQ6VeMY.o(.text+0x4e): In function `main':
: undefined reference to `atan'
/tmp/ccQ6VeMY.o(.text+0x62): In function `main':
: undefined reference to `atan'
/tmp/ccQ6VeMY.o(.text+0x7e): In function `main':
: undefined reference to `atan'
collect2: ld returned 1 exit status
peter@cordelia:~> gcc -v
Reading specs from /usr/lib/gcc-lib/i586-suse-linux/3.3.1/specs
Configured with: ../configure --enable-threads=posix --prefix=/usr --with-local-prefix=/usr/local --infodir=/usr/share/info --mandir=/usr/share/man --libdir=/usr/lib --enable-languages=c,c++,f77,objc,java,ada --disable-checking --enable-libgcj --with-gxx-include-dir=/usr/include/g++ --with-slibdir=/lib --with-system-zlib --enable-shared --enable-__cxa_atexit i586-suse-linux
Thread model: posix
gcc version 3.3.1 (SuSE Linux)
peter@cordelia:~>


Peter
[link|http://www.debian.org|Shill For Hire]
[link|http://www.kuro5hin.org|There is no K5 Cabal]
[link|http://guildenstern.dyndns.org|Blog]
New Gotta add -lm for math library
-drl
     Newbie C++ Builder problem with overflow. - (Another Scott) - (25)
         Re: Newbie C++ Builder problem with overflow. - (deSitter) - (19)
             Second paragraph in deS msg explains it - (Arkadiy) - (1)
                 Thanks! That did it. - (Another Scott)
             You're speaking over my head. - (Another Scott) - (16)
                 Re: You're speaking over my head. - (deSitter) - (15)
                     Thanks for the tips. Greatly appreciated. -NT - (Another Scott)
                     Actually, Ross... - (jb4) - (13)
                         Re: Actually, Ross... - (deSitter) - (12)
                             Hrm? - (jb4) - (11)
                                 Re: Hrm? - (deSitter) - (10)
                                     So what iron is that running on? - (jb4) - (9)
                                         Re: So what iron is that running on? - (deSitter)
                                         Also 12 on HPQ Presario 5831 (500 MHz Athlon)/gcc 2.95.4 -NT - (scoenye) - (7)
                                             Re: Also 12 on HPQ Presario 5831 (500 MHz Athlon)/gcc 2.95.4 - (jb4) - (6)
                                                 Re: Also 12 on HPQ Presario 5831 (500 MHz Athlon)/gcc 2.95.4 - (deSitter) - (5)
                                                     Sorry Ross: No Sale - (jb4) - (2)
                                                         Re: Sorry Ross: No Sale - (deSitter) - (1)
                                                             Please stand by... - (jb4)
                                                     Doesn't compile here - (pwhysall) - (1)
                                                         Gotta add -lm for math library -NT - (deSitter)
         Somewhat related: Borland Builder-IDE "style" issue. - (CRConrad) - (2)
             Well, I'm trying to reuse some earlier code. - (Another Scott)
             Dude.... - (jb4)
         NORM1 is a float, but - (jb4) - (1)
             Thanks! - (Another Scott)

Ever since then, I can easily spot a sociopathic liar.
61 ms