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Diffstat (limited to 'runtime/ia32/i64_udivmod.S')
| -rw-r--r-- | runtime/ia32/i64_udivmod.S | 104 |
1 files changed, 0 insertions, 104 deletions
diff --git a/runtime/ia32/i64_udivmod.S b/runtime/ia32/i64_udivmod.S deleted file mode 100644 index dccfc286..00000000 --- a/runtime/ia32/i64_udivmod.S +++ /dev/null @@ -1,104 +0,0 @@ -// ***************************************************************** -// -// The Compcert verified compiler -// -// Xavier Leroy, INRIA Paris-Rocquencourt -// -// Copyright (c) 2013 Institut National de Recherche en Informatique et -// en Automatique. -// -// Redistribution and use in source and binary forms, with or without -// modification, are permitted provided that the following conditions are met: -// * Redistributions of source code must retain the above copyright -// notice, this list of conditions and the following disclaimer. -// * Redistributions in binary form must reproduce the above copyright -// notice, this list of conditions and the following disclaimer in the -// documentation and/or other materials provided with the distribution. -// * Neither the name of the <organization> nor the -// names of its contributors may be used to endorse or promote products -// derived from this software without specific prior written permission. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT -// HOLDER> BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, -// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, -// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR -// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF -// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING -// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS -// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -// -// ********************************************************************* - -// Helper functions for 64-bit integer arithmetic. IA32 version. - -#include "sysdeps.h" - -// Division and remainder - -// Auxiliary function, never called directly from C code -// Input: 20(esp), 24(esp) is dividend N -// 28(esp), 32(esp) is divisor D -// Output: esi:edi is quotient Q -// eax:edx is remainder R -// ebp is preserved - -FUNCTION(__i64_udivmod) - cmpl $0, 32(%esp) // single-word divisor? (DH = 0) - jne 1f - // Special case 64 bits divided by 32 bits - movl 28(%esp), %ecx // divide NH by DL - movl 24(%esp), %eax // (will trap if D = 0) - xorl %edx, %edx - divl %ecx // eax = quotient, edx = remainder - movl %eax, %edi // high word of quotient in edi - movl 20(%esp), %eax // divide rem : NL by DL - divl %ecx // eax = quotient, edx = remainder - movl %eax, %esi // low word of quotient in esi */ - movl %edx, %eax // low word of remainder in eax - xorl %edx, %edx // high word of remainder is 0, in edx - ret - // The general case -1: movl 28(%esp), %ecx // esi:ecx = D - movl 32(%esp), %esi - movl 20(%esp), %eax // edx:eax = N - movl 24(%esp), %edx - // Scale D and N down, giving D' and N', until D' fits in 32 bits -2: shrl $1, %esi // shift D' right by one - rcrl $1, %ecx - shrl $1, %edx // shift N' right by one - rcrl $1, %eax - testl %esi, %esi // repeat until D'H = 0 - jnz 2b - // Divide N' by D' to get an approximate quotient - divl %ecx // eax = quotient, edx = remainder - movl %eax, %esi // save tentative quotient Q in esi - // Check for off by one quotient - // Compute Q * D -3: movl 32(%esp), %ecx - imull %esi, %ecx // ecx = Q * DH - movl 28(%esp), %eax - mull %esi // edx:eax = Q * DL - add %ecx, %edx // edx:eax = Q * D - jc 5f // overflow in addition means Q is too high - // Compare Q * D with N, computing the remainder in the process - movl %eax, %ecx - movl 20(%esp), %eax - subl %ecx, %eax - movl %edx, %ecx - movl 24(%esp), %edx - sbbl %ecx, %edx // edx:eax = N - Q * D - jnc 4f // no carry: N >= Q * D, we are fine - decl %esi // carry: N < Q * D, adjust Q down by 1 - addl 28(%esp), %eax // and remainder up by D - adcl 32(%esp), %edx - // Finished -4: xorl %edi, %edi // high half of quotient is 0 - ret - // Special case when Q * D overflows -5: decl %esi // adjust Q down by 1 - jmp 3b // and redo check & computation of remainder - -ENDFUNCTION(__i64_udivmod) |