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F2I/F2L fix: NaN→0, +Inf→MAX_VALUE #462

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F2I/F2L fix: NaN→0, +Inf→MAX_VALUE #462

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62 changes: 61 additions & 1 deletion core/src/core/org/jnode/vm/x86/compiler/l1a/IntItem.java
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,9 @@

package org.jnode.vm.x86.compiler.l1a;

import org.jnode.assembler.Label;
import org.jnode.assembler.x86.X86Assembler;
import org.jnode.assembler.x86.X86Constants;
import org.jnode.assembler.x86.X86Register;
import org.jnode.assembler.x86.X86Register.GPR;
import org.jnode.vm.JvmType;
Expand All @@ -34,6 +36,8 @@

final class IntItem extends WordItem {

private static int labelCounter;

private int value;

final void initialize(EmitterContext ec, byte kind, short offsetToFP, X86Register reg, int value) {
Expand Down Expand Up @@ -84,14 +88,70 @@ protected void loadToConstant(EmitterContext ec, X86Assembler os,
}

/**
* Pop the top of the FPU stack into the given memory location.
* Pop the top of the FPU stack into the given memory location,
* with JLS-correct handling for NaN, infinity, and overflow.
*
* @param os
* @param reg
* @param disp
*/
protected void popFromFPU(X86Assembler os, GPR reg, int disp) {
final String uid = "f2i_" + (++labelCounter) + "_";
final Label done = new Label(uid + "fix");
final Label overflow = new Label(uid + "ovf");
final Label isInf = new Label(uid + "inf");

os.writePUSH(X86Register.EAX);

// Save float copy at [reg+disp-4], then reload for FISTP
os.writeFSTP32(reg, disp - 4);
os.writeFLD32(reg, disp - 4);
os.writeFISTP32(reg, disp);

// Check if result == MIN_VALUE (indefinite integer)
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp);
os.writeCMP_Const(X86Register.EAX, 0x80000000);
os.writeJCC(done, X86Constants.JNE);

// Check saved float for NaN/Infinity (exponent all 1s?)
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeAND(X86Register.EAX, 0x7F800000);
os.writeCMP_Const(X86Register.EAX, 0x7F800000);
os.writeJCC(overflow, X86Constants.JNE);

// NaN or Infinity
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeTEST(X86Register.EAX, 0x007FFFFF);
os.writeJCC(isInf, X86Constants.JZ);

// NaN -> 0
os.writeXOR(X86Register.EAX, X86Register.EAX);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);
os.writeJMP(done);

// Infinity
os.setObjectRef(isInf);
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeTEST(X86Register.EAX, 0x80000000);
os.writeJCC(done, X86Constants.JNZ); // -Inf -> MIN_VALUE (correct)

// +Inf -> MAX_VALUE
os.writeMOV_Const(X86Register.EAX, 0x7FFFFFFF);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);
os.writeJMP(done);

// Not NaN/Inf, but result is MIN_VALUE: overflow or genuine MIN_VALUE
os.setObjectRef(overflow);
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeTEST(X86Register.EAX, 0x80000000);
os.writeJCC(done, X86Constants.JNZ); // Negative -> keep MIN_VALUE

// Positive overflow -> MAX_VALUE
os.writeMOV_Const(X86Register.EAX, 0x7FFFFFFF);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);

os.setObjectRef(done);
os.writePOP(X86Register.EAX);
}

/**
Expand Down
83 changes: 82 additions & 1 deletion core/src/core/org/jnode/vm/x86/compiler/l1a/LongItem.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,9 @@

package org.jnode.vm.x86.compiler.l1a;

import org.jnode.assembler.Label;
import org.jnode.assembler.x86.X86Assembler;
import org.jnode.assembler.x86.X86Constants;
import org.jnode.assembler.x86.X86Register;
import org.jnode.assembler.x86.X86Register.GPR;
import org.jnode.assembler.x86.X86Register.GPR32;
Expand All @@ -38,6 +40,8 @@
*/
final class LongItem extends DoubleWordItem {

private static int labelCounter;

private long value;

/**
Expand Down Expand Up @@ -100,14 +104,91 @@ protected final void loadToConstant64(EmitterContext ec, X86Assembler os,
}

/**
* Pop the top of the FPU stack into the given memory location.
* Pop the top of the FPU stack into the given memory location,
* with JLS-correct handling for NaN, infinity, and overflow.
*
* @param os
* @param reg
* @param disp
*/
protected void popFromFPU(X86Assembler os, GPR reg, int disp) {
final String uid = "f2l_" + (++labelCounter) + "_";
final Label done = new Label(uid + "fix");
final Label overflow = new Label(uid + "ovf");
final Label isInf = new Label(uid + "inf");
final Label isInf2 = new Label(uid + "inf2");

os.writePUSH(X86Register.EAX);

// Save double copy at [reg+disp-8], then reload for FISTP
os.writeFSTP64(reg, disp - 8);
os.writeFLD64(reg, disp - 8);
os.writeFISTP64(reg, disp);

// Check if 64-bit result == Long.MIN_VALUE (indefinite integer)
// Check low 32 bits == 0
os.writeCMP_Const(X86Constants.BITS32, reg, disp, 0);
os.writeJCC(done, X86Constants.JNE);
// Check high 32 bits == 0x80000000
os.writeCMP_Const(X86Constants.BITS32, reg, disp + 4, 0x80000000);
os.writeJCC(done, X86Constants.JNE);

// Check saved double for NaN/Infinity
// Double high word at [reg+disp-4]: exponent bits 30:20 = 0x7FF00000
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeAND(X86Register.EAX, 0x7FF00000);
os.writeCMP_Const(X86Register.EAX, 0x7FF00000);
os.writeJCC(overflow, X86Constants.JNE);

// NaN or Infinity: check mantissa
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 8);
os.writeTEST(X86Register.EAX, X86Register.EAX);
os.writeJCC(isInf, X86Constants.JZ);
// NaN (low mantissa != 0)
os.writeXOR(X86Register.EAX, X86Register.EAX);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);
os.writeMOV(X86Constants.BITS32, reg, disp + 4, X86Register.EAX);
os.writeJMP(done);

// Check high mantissa bits
os.setObjectRef(isInf);
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeAND(X86Register.EAX, 0x000FFFFF);
os.writeTEST(X86Register.EAX, X86Register.EAX);
os.writeJCC(isInf2, X86Constants.JZ);
// NaN (high mantissa != 0)
os.writeXOR(X86Register.EAX, X86Register.EAX);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);
os.writeMOV(X86Constants.BITS32, reg, disp + 4, X86Register.EAX);
os.writeJMP(done);

// Infinity
os.setObjectRef(isInf2);
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeTEST(X86Register.EAX, 0x80000000);
os.writeJCC(done, X86Constants.JNZ); // -Inf -> MIN_VALUE (correct)

// +Inf -> MAX_VALUE
os.writeMOV_Const(X86Register.EAX, 0xFFFFFFFF);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);
os.writeMOV_Const(X86Register.EAX, 0x7FFFFFFF);
os.writeMOV(X86Constants.BITS32, reg, disp + 4, X86Register.EAX);
os.writeJMP(done);

// Not NaN/Inf, but result is MIN_VALUE: overflow or genuine MIN_VALUE
os.setObjectRef(overflow);
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeTEST(X86Register.EAX, 0x80000000);
os.writeJCC(done, X86Constants.JNZ); // Negative -> keep MIN_VALUE

// Positive overflow -> MAX_VALUE
os.writeMOV_Const(X86Register.EAX, 0xFFFFFFFF);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);
os.writeMOV_Const(X86Register.EAX, 0x7FFFFFFF);
os.writeMOV(X86Constants.BITS32, reg, disp + 4, X86Register.EAX);

os.setObjectRef(done);
os.writePOP(X86Register.EAX);
}

/**
Expand Down
62 changes: 61 additions & 1 deletion core/src/core/org/jnode/vm/x86/compiler/l1b/IntItem.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,9 @@

package org.jnode.vm.x86.compiler.l1b;

import org.jnode.assembler.Label;
import org.jnode.assembler.x86.X86Assembler;
import org.jnode.assembler.x86.X86Constants;
import org.jnode.assembler.x86.X86Register;
import org.jnode.assembler.x86.X86Register.GPR;
import org.jnode.vm.JvmType;
Expand All @@ -35,6 +37,8 @@

final class IntItem extends WordItem implements X86CompilerConstants {

private static int labelCounter;

private int value;

final void initialize(EmitterContext ec, byte kind, short offsetToFP, X86Register reg, int value) {
Expand Down Expand Up @@ -85,14 +89,70 @@ protected void loadToConstant(EmitterContext ec, X86Assembler os,
}

/**
* Pop the top of the FPU stack into the given memory location.
* Pop the top of the FPU stack into the given memory location,
* with JLS-correct handling for NaN, infinity, and overflow.
*
* @param os
* @param reg
* @param disp
*/
protected void popFromFPU(X86Assembler os, GPR reg, int disp) {
final String uid = "f2i_" + (++labelCounter) + "_";
final Label done = new Label(uid + "fix");
final Label overflow = new Label(uid + "ovf");
final Label isInf = new Label(uid + "inf");

os.writePUSH(X86Register.EAX);

// Save float copy at [reg+disp-4], then reload for FISTP
os.writeFSTP32(reg, disp - 4);
os.writeFLD32(reg, disp - 4);
os.writeFISTP32(reg, disp);

// Check if result == MIN_VALUE (indefinite integer)
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp);
os.writeCMP_Const(X86Register.EAX, 0x80000000);
os.writeJCC(done, X86Constants.JNE);

// Check saved float for NaN/Infinity (exponent all 1s?)
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeAND(X86Register.EAX, 0x7F800000);
os.writeCMP_Const(X86Register.EAX, 0x7F800000);
os.writeJCC(overflow, X86Constants.JNE);

// NaN or Infinity
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeTEST(X86Register.EAX, 0x007FFFFF);
os.writeJCC(isInf, X86Constants.JZ);

// NaN -> 0
os.writeXOR(X86Register.EAX, X86Register.EAX);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);
os.writeJMP(done);

// Infinity
os.setObjectRef(isInf);
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeTEST(X86Register.EAX, 0x80000000);
os.writeJCC(done, X86Constants.JNZ); // -Inf -> MIN_VALUE (correct)

// +Inf -> MAX_VALUE
os.writeMOV_Const(X86Register.EAX, 0x7FFFFFFF);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);
os.writeJMP(done);

// Not NaN/Inf, but result is MIN_VALUE: overflow or genuine MIN_VALUE
os.setObjectRef(overflow);
os.writeMOV(X86Constants.BITS32, X86Register.EAX, reg, disp - 4);
os.writeTEST(X86Register.EAX, 0x80000000);
os.writeJCC(done, X86Constants.JNZ); // Negative -> keep MIN_VALUE

// Positive overflow -> MAX_VALUE
os.writeMOV_Const(X86Register.EAX, 0x7FFFFFFF);
os.writeMOV(X86Constants.BITS32, reg, disp, X86Register.EAX);

os.setObjectRef(done);
os.writePOP(X86Register.EAX);
}

/**
Expand Down
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