<p>Use <code>/fp:strict</code> on Windows to tell the compiler to produce code that strictly follows IEEE 754, and <code>gcc -msse2 -mfpmath=sse</code> on Linux to obtain the same behavior there.</p>

<p>The reasons for the differences you are seeing have been discussed in spots on StackOverflow, but the best survey is David Monniaux's <a href="http://arxiv.org/abs/cs/0701192" rel="nofollow">article</a>.</p>

<hr>

<p>The assembly instructions I obtain when compiling with <code>gcc -msse2 -mpfmath=sse</code> are as follow. Instructions <code>cvtsi2ssq</code>, <code>divss</code>, <code>mulss</code>, <code>addss</code> are the correct instructions to use, and they result in a program where <code>p_value</code> contains at one point <code>42d5d1ec</code>.</p>

<pre><code>    .globl  _main
    .align  4, 0x90
_main:                                  ## @main
    .cfi_startproc
## BB#0:
    pushq   %rbp
Ltmp2:
    .cfi_def_cfa_offset 16
Ltmp3:
    .cfi_offset %rbp, -16
    movq    %rsp, %rbp
Ltmp4:
    .cfi_def_cfa_register %rbp
    subq    $32, %rsp
    movl    $0, -4(%rbp)
    movl    $0, -8(%rbp)
LBB0_1:                                 ## =&gt;This Inner Loop Header: Depth=1
    cmpl    $100000, -8(%rbp)       ## imm = 0x186A0
    jge LBB0_4
## BB#2:                                ##   in Loop: Header=BB0_1 Depth=1
    movq    _p_value@GOTPCREL(%rip), %rax
    movabsq $100, %rcx
    cvtsi2ssq   %rcx, %xmm0
    movss   LCPI0_0(%rip), %xmm1
    movabsq $10, %rcx
    cvtsi2ssq   %rcx, %xmm2
    cvtsi2ss    -8(%rbp), %xmm3
    divss   %xmm3, %xmm2
    movss   %xmm2, -12(%rbp)
    cvtsi2ss    -8(%rbp), %xmm2
    mulss   %xmm2, %xmm1
    addss   %xmm0, %xmm1
    movss   %xmm1, (%rax)
    movl    (%rax), %edx
    movl    %edx, -16(%rbp)
    leaq    L_.str(%rip), %rdi
    movl    -16(%rbp), %esi
    movb    $0, %al
    callq   _printf
    movl    %eax, -20(%rbp)         ## 4-byte Spill
## BB#3:                                ##   in Loop: Header=BB0_1 Depth=1
    movl    -8(%rbp), %eax
    addl    $1, %eax
    movl    %eax, -8(%rbp)
    jmp LBB0_1
LBB0_4:
    movl    -4(%rbp), %eax
    addq    $32, %rsp
    popq    %rbp
    ret
</code></pre>
Is there any way to make sure the floating point arithmetic result the same in both linux and windows
<p>My programe runs both in linux and windows, I have to make sure the floating point arithmetic get the same result in different OS.</p>

<p>Here is the code:</p>

<pre><code>for (int i = 0; i &lt; 100000; ++i)
{
    float d_value = 10.0f / float(i);
    float p_value = 0.01f * float(i) + 100.0f;
}
</code></pre>

<p>I use "<strong>g++ -m32 -c -static -g -O0 -ffloat-store</strong>" to build the code in linux.
I use "/fp:precise /O2" to build the code in windows with vs2005.</p>

<p>When I printf the "d_value" and the "p_value", the "d_value" is all the same both in linux and windows. But the "p_value" is different sometimes. 
For exsample, print the "p_value" with hexadecimal format:</p>

<pre><code>windows:  42d5d1eb
linux:    42d5d1ec
</code></pre>

<p>Why dose this happen?</p>

<p>My g++ version is</p>

<pre><code>Configured with: ../src/configure -v --with-pkgversion='Debian 4.4.5-8' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.4 --enable-shared --enable-multiarch --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.4 --libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --enable-targets=all --with-arch-32=i586 --with-tune=generic --enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu --target=i486-linux-gnu
Thread model: posix
gcc version 4.4.5 (Debian 4.4.5-8)
</code></pre>

<p>I use the flag <code>-ffloat-store</code>, because of someone's suggestion here: <a href="https://stackoverflow.com/questions/1961442/different-math-rounding-behaviour-between-linux-mac-os-x-and-windows">Different math rounding behaviour between Linux, Mac OS X and Windows</a></p>