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fix a couple of 64-bit-op-on-32-bit-system bugs

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We weren't properly handling the case where a 64-bit value is
multipled with itself in multiplyRR, leading to wrong code.  Also,
addCarryCR didn't know how to handle constants more than 8-bits wide.
This commit is contained in:
Joel Dice 2010-11-30 16:58:51 -07:00
parent 19dca18cd0
commit 1d9489a76e
2 changed files with 39 additions and 6 deletions
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28
src/x86.cpp
View File

@ -1403,17 +1403,18 @@ addRR(Context* c, unsigned aSize, Assembler::Register* a,
}
void
addCarryCR(Context* c, unsigned size UNUSED, Assembler::Constant* a,
addCarryCR(Context* c, unsigned size, Assembler::Constant* a,
Assembler::Register* b)
{
int64_t v = a->value->value();
maybeRex(c, size, b);
if (isInt8(v)) {
maybeRex(c, size, b);
opcode(c, 0x83, 0xd0 + regCode(b));
c->code.append(v);
} else {
abort(c);
opcode(c, 0x81, 0xd0 + regCode(b));
c->code.append4(v);
}
}
@ -1740,16 +1741,31 @@ multiplyRR(Context* c, unsigned aSize, Assembler::Register* a,
Assembler::Register ah(a->high);
Assembler::Register bh(b->high);
Assembler::Register tmp(-1);
Assembler::Register* scratch;
if (a->low == b->low) {
tmp.low = c->client->acquireTemporary
(GeneralRegisterMask & ~(1 << rax));
scratch = &tmp;
moveRR(c, 4, b, 4, scratch);
} else {
scratch = b;
}
moveRR(c, 4, b, 4, &axdx);
multiplyRR(c, 4, &ah, 4, b);
multiplyRR(c, 4, &ah, 4, scratch);
multiplyRR(c, 4, a, 4, &bh);
addRR(c, 4, &bh, 4, b);
addRR(c, 4, &bh, 4, scratch);
// mul a->low,%eax%edx
opcode(c, 0xf7, 0xe0 + a->low);
addRR(c, 4, b, 4, &bh);
addRR(c, 4, scratch, 4, &bh);
moveRR(c, 4, &axdx, 4, b);
if (tmp.low != -1) {
c->client->releaseTemporary(tmp.low);
}
} else {
maybeRex(c, aSize, b, a);
opcode(c, 0x0f, 0xaf);

17
test/Longs.java
View File

@ -243,6 +243,23 @@ public class Longs {
expect(buffer.getLong() == 231);
expect(unsignedShiftRight32(231) == 0);
{ int[] x = new int[] { 1701899151 };
int[] z = new int[x.length * 2];
final long LONG_MASK = 0xffffffffL;
int lastProductLowWord = 0;
for (int j=0, i=0; j<x.length; j++) {
long piece = (x[j] & LONG_MASK);
long product = piece * piece;
z[i++] = (lastProductLowWord << 31) | (int) (product >>> 33);
z[i++] = (int) (product >>> 1);
lastProductLowWord = (int) product;
}
expect(z[0] == 337192406);
expect(z[1] == -437261072);
}
}
}