/** @file | |
Compiler intrinsic for 64-bit compare, ported from LLVM code. | |
Copyright (c) 2008-2009, Apple Inc. All rights reserved.<BR> | |
This program and the accompanying materials | |
are licensed and made available under the terms and conditions of the BSD License | |
which accompanies this distribution. The full text of the license may be found at | |
http://opensource.org/licenses/bsd-license.php | |
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, | |
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. | |
**/ | |
/** | |
University of Illinois/NCSA | |
Open Source License | |
Copyright (c) 2003-2008 University of Illinois at Urbana-Champaign. | |
All rights reserved. | |
Developed by: | |
LLVM Team | |
University of Illinois at Urbana-Champaign | |
http://llvm.org | |
Permission is hereby granted, free of charge, to any person obtaining a copy of | |
this software and associated documentation files (the "Software"), to deal with | |
the Software without restriction, including without limitation the rights to | |
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies | |
of the Software, and to permit persons to whom the Software is furnished to do | |
so, subject to the following conditions: | |
* Redistributions of source code must retain the above copyright notice, | |
this list of conditions and the following disclaimers. | |
* Redistributions in binary form must reproduce the above copyright notice, | |
this list of conditions and the following disclaimers in the | |
documentation and/or other materials provided with the distribution. | |
* Neither the names of the LLVM Team, University of Illinois at | |
Urbana-Champaign, nor the names of its contributors may be used to | |
endorse or promote products derived from this Software without specific | |
prior written permission. | |
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS | |
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE | |
SOFTWARE. | |
**/ | |
#include "Llvm_int_lib.h" | |
// Effects: if rem != 0, *rem = a % b | |
// Returns: a / b | |
// Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide | |
UINT64 | |
__udivmoddi4 (UINT64 a, UINT64 b, UINT64* rem) | |
{ | |
const unsigned n_uword_bits = sizeof(UINT32) * CHAR_BIT; | |
const unsigned n_udword_bits = sizeof(UINT64) * CHAR_BIT; | |
udwords n; | |
n.all = a; | |
udwords d; | |
d.all = b; | |
udwords q; | |
udwords r; | |
unsigned sr; | |
if (b == 0) { | |
// ASSERT (FALSE); | |
return 0; | |
} | |
// special cases, X is unknown, K != 0 | |
if (n.high == 0) | |
{ | |
if (d.high == 0) | |
{ | |
// 0 X | |
// --- | |
// 0 X | |
if (rem) | |
*rem = n.low % d.low; | |
return n.low / d.low; | |
} | |
// 0 X | |
// --- | |
// K X | |
if (rem) | |
*rem = n.low; | |
return 0; | |
} | |
// n.high != 0 | |
if (d.low == 0) | |
{ | |
if (d.high == 0) | |
{ | |
// K X | |
// --- | |
// 0 0 | |
if (rem) | |
*rem = n.high % d.low; | |
return n.high / d.low; | |
} | |
// d.high != 0 | |
if (n.low == 0) | |
{ | |
// K 0 | |
// --- | |
// K 0 | |
if (rem) | |
{ | |
r.high = n.high % d.high; | |
r.low = 0; | |
*rem = r.all; | |
} | |
return n.high / d.high; | |
} | |
// K K | |
// --- | |
// K 0 | |
if ((d.high & (d.high - 1)) == 0) // if d is a power of 2 | |
{ | |
if (rem) | |
{ | |
r.low = n.low; | |
r.high = n.high & (d.high - 1); | |
*rem = r.all; | |
} | |
return n.high >> COUNT_TRAILING_ZEROS(d.high); | |
} | |
// K K | |
// --- | |
// K 0 | |
sr = COUNT_LEADING_ZEROS(d.high) - COUNT_LEADING_ZEROS(n.high); | |
// 0 <= sr <= n_uword_bits - 2 or sr large | |
if (sr > n_uword_bits - 2) | |
{ | |
if (rem) | |
*rem = n.all; | |
return 0; | |
} | |
++sr; | |
// 1 <= sr <= n_uword_bits - 1 | |
// q.all = n.all << (n_udword_bits - sr); | |
q.low = 0; | |
q.high = n.low << (n_uword_bits - sr); | |
// r.all = n.all >> sr; | |
r.high = n.high >> sr; | |
r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr); | |
} | |
else // d.low != 0 | |
{ | |
if (d.high == 0) | |
{ | |
// K X | |
// --- | |
// 0 K | |
if ((d.low & (d.low - 1)) == 0) // if d is a power of 2 | |
{ | |
if (rem) | |
*rem = n.low & (d.low - 1); | |
if (d.low == 1) | |
return n.all; | |
unsigned sr = COUNT_TRAILING_ZEROS(d.low); | |
q.high = n.high >> sr; | |
q.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr); | |
return q.all; | |
} | |
// K X | |
// --- | |
// 0 K | |
sr = 1 + n_uword_bits + COUNT_LEADING_ZEROS(d.low) - COUNT_LEADING_ZEROS(n.high); | |
// 2 <= sr <= n_udword_bits - 1 | |
// q.all = n.all << (n_udword_bits - sr); | |
// r.all = n.all >> sr; | |
// if (sr == n_uword_bits) | |
// { | |
// q.low = 0; | |
// q.high = n.low; | |
// r.high = 0; | |
// r.low = n.high; | |
// } | |
// else if (sr < n_uword_bits) // 2 <= sr <= n_uword_bits - 1 | |
// { | |
// q.low = 0; | |
// q.high = n.low << (n_uword_bits - sr); | |
// r.high = n.high >> sr; | |
// r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr); | |
// } | |
// else // n_uword_bits + 1 <= sr <= n_udword_bits - 1 | |
// { | |
// q.low = n.low << (n_udword_bits - sr); | |
// q.high = (n.high << (n_udword_bits - sr)) | | |
// (n.low >> (sr - n_uword_bits)); | |
// r.high = 0; | |
// r.low = n.high >> (sr - n_uword_bits); | |
// } | |
q.low = (n.low << (n_udword_bits - sr)) & | |
((INT32)(n_uword_bits - sr) >> (n_uword_bits-1)); | |
q.high = ((n.low << ( n_uword_bits - sr)) & | |
((INT32)(sr - n_uword_bits - 1) >> (n_uword_bits-1))) | | |
(((n.high << (n_udword_bits - sr)) | | |
(n.low >> (sr - n_uword_bits))) & | |
((INT32)(n_uword_bits - sr) >> (n_uword_bits-1))); | |
r.high = (n.high >> sr) & | |
((INT32)(sr - n_uword_bits) >> (n_uword_bits-1)); | |
r.low = ((n.high >> (sr - n_uword_bits)) & | |
((INT32)(n_uword_bits - sr - 1) >> (n_uword_bits-1))) | | |
(((n.high << (n_uword_bits - sr)) | | |
(n.low >> sr)) & | |
((INT32)(sr - n_uword_bits) >> (n_uword_bits-1))); | |
} | |
else | |
{ | |
// K X | |
// --- | |
// K K | |
sr = COUNT_LEADING_ZEROS(d.high) - COUNT_LEADING_ZEROS(n.high); | |
// 0 <= sr <= n_uword_bits - 1 or sr large | |
if (sr > n_uword_bits - 1) | |
{ | |
if (rem) | |
*rem = n.all; | |
return 0; | |
} | |
++sr; | |
// 1 <= sr <= n_uword_bits | |
// q.all = n.all << (n_udword_bits - sr); | |
q.low = 0; | |
q.high = n.low << (n_uword_bits - sr); | |
// r.all = n.all >> sr; | |
// if (sr < n_uword_bits) | |
// { | |
// r.high = n.high >> sr; | |
// r.low = (n.high << (n_uword_bits - sr)) | (n.low >> sr); | |
// } | |
// else | |
// { | |
// r.high = 0; | |
// r.low = n.high; | |
// } | |
r.high = (n.high >> sr) & | |
((INT32)(sr - n_uword_bits) >> (n_uword_bits-1)); | |
r.low = (n.high << (n_uword_bits - sr)) | | |
((n.low >> sr) & | |
((INT32)(sr - n_uword_bits) >> (n_uword_bits-1))); | |
} | |
} | |
// Not a special case | |
// q and r are initialized with: | |
// q.all = n.all << (n_udword_bits - sr); | |
// r.all = n.all >> sr; | |
// 1 <= sr <= n_udword_bits - 1 | |
UINT32 carry = 0; | |
for (; sr > 0; --sr) | |
{ | |
// r:q = ((r:q) << 1) | carry | |
r.high = (r.high << 1) | (r.low >> (n_uword_bits - 1)); | |
r.low = (r.low << 1) | (q.high >> (n_uword_bits - 1)); | |
q.high = (q.high << 1) | (q.low >> (n_uword_bits - 1)); | |
q.low = (q.low << 1) | carry; | |
// carry = 0; | |
// if (r.all >= d.all) | |
// { | |
// r.all -= d.all; | |
// carry = 1; | |
// } | |
const INT64 s = (INT64)(d.all - r.all - 1) >> (n_udword_bits - 1); | |
carry = s & 1; | |
r.all -= d.all & s; | |
} | |
q.all = (q.all << 1) | carry; | |
if (rem) | |
*rem = r.all; | |
return q.all; | |
} |