6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-09-28 22:55:52 +00:00
Code Issues Projects Releases Wiki Activity

fixup magic constant making code. tested by thousands of random divisions.... by 10000. ok, so random divisors would be good too, but this at least fixes some things

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21140 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Lenharth 2005-04-07 17:19:16 +00:00
parent 9bf59d7ed2
commit 320174f009
1 changed files with 10 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
lib/Target/Alpha/AlphaISelPattern.cpp
View File

@ -413,7 +413,7 @@ static struct ms magic(int64_t d) {
ad = abs(d);
t = two63 + ((uint64_t)d >> 63);
anc = t - 1 - t%ad; // absolute value of nc
p = 31; // initialize p
p = 63; // initialize p
q1 = two63/anc; // initialize q1 = 2p/abs(nc)
r1 = two63 - q1*anc; // initialize r1 = rem(2p,abs(nc))
q2 = two63/ad; // initialize q2 = 2p/abs(d)
@ -450,11 +450,11 @@ static struct mu magicu(uint64_t d)
struct mu magu;
magu.a = 0; // initialize "add" indicator
nc = - 1 - (-d)%d;
p = 31; // initialize p
q1 = 0x8000000000000000ll/nc; // initialize q1 = 2p/nc
r1 = 0x8000000000000000ll - q1*nc; // initialize r1 = rem(2p,nc)
q2 = 0x7FFFFFFFFFFFFFFFll/d; // initialize q2 = (2p-1)/d
r2 = 0x7FFFFFFFFFFFFFFFll - q2*d; // initialize r2 = rem((2p-1),d)
p = 63; // initialize p
q1 = 0x8000000000000000ull/nc; // initialize q1 = 2p/nc
r1 = 0x8000000000000000ull - q1*nc; // initialize r1 = rem(2p,nc)
q2 = 0x7FFFFFFFFFFFFFFFull/d; // initialize q2 = (2p-1)/d
r2 = 0x7FFFFFFFFFFFFFFFull - q2*d; // initialize r2 = rem((2p-1),d)
do {
p = p + 1;
if (r1 >= nc - r1 ) {
@ -466,19 +466,19 @@ static struct mu magicu(uint64_t d)
r1 = 2*r1; // update r1
}
if (r2 + 1 >= d - r2) {
if (q2 >= 0x7FFFFFFFFFFFFFFFll) magu.a = 1;
if (q2 >= 0x7FFFFFFFFFFFFFFFull) magu.a = 1;
q2 = 2*q2 + 1; // update q2
r2 = 2*r2 + 1 - d; // update r2
}
else {
if (q2 >= 0x8000000000000000ll) magu.a = 1;
if (q2 >= 0x8000000000000000ull) magu.a = 1;
q2 = 2*q2; // update q2
r2 = 2*r2 + 1; // update r2
}
delta = d - 1 - r2;
} while (p < 64 && (q1 < delta || (q1 == delta && r1 == 0)));
magu.m = q2 + 1; // resulting magic number
magu.s = p - 32; // resulting shift
magu.s = p - 64; // resulting shift
return magu;
}
@ -487,7 +487,7 @@ static struct mu magicu(uint64_t d)
/// multiplying by a magic number. See:
/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
SDOperand ISel::BuildSDIVSequence(SDOperand N) {
int d = (int)cast<ConstantSDNode>(N.getOperand(1))->getSignExtended();
int64_t d = (int64_t)cast<ConstantSDNode>(N.getOperand(1))->getSignExtended();
ms magics = magic(d);
// Multiply the numerator (operand 0) by the magic value
SDOperand Q = ISelDAG->getNode(ISD::MULHS, MVT::i64, N.getOperand(0),