protected override void DecodePartial()
{
int count = base.Count;
System.Diagnostics.Debug.Assert(count > 0 && count < 5);
// According to Table 7-13, "Missing components of exception Branch address packets"
// then after a partial branch, we're always in "no exception" state
base.ExceptionType = TArmExceptionType.ENone;
if (count == 1)
{
// The single-byte packet is exactly the same as in the original encoding
base.DecodePartial();
}
else
{
// We have full 5 bytes of address info.
SymMask maskFirst = new SymMask(0x7E, SymMask.TShiftDirection.ERight, 1);
SymMask maskMiddle = new SymMask(0x7F);
SymMask maskLast = new SymMask(0x3F);
SymByte b;
SymAddressWithKnownBits address = new SymAddressWithKnownBits();
uint masked = 0;
// First byte
b = base[0];
address.KnownBits += 6;
address.Address |= maskFirst.Apply(b);
// Middle bytes, but not the last
for (int i = 1; i < count - 1; i++)
{
b = base[i];
b = (byte)maskMiddle.Apply(b);
masked = (uint)(b << address.KnownBits);
address.KnownBits += 7;
address.Address |= masked;
}
// Last byte
b = base.LastByte;
address.KnownBits += 6;
address.Address |= maskLast.Apply(b);
// Shift entire address by shift count based upon current instruction set.
int isShift = ETMBranchDecoder.CompressionLeftShiftCount(base.InstructionSet);
address.KnownBits += isShift;
address.Address <<= isShift;
// Save address
base.BranchAddress = address;
}
}
public static ETMBranchDecoder New(ETMStateData aStateData)
{
ETMBranchDecoder ret = null;
//
switch (aStateData.Config.BranchCompressionScheme)
{
default:
case TETMBranchCompressionScheme.EOriginal:
ret = new ETMBranchDecoderOriginal(aStateData);
break;
case TETMBranchCompressionScheme.EAlternative:
ret = new ETMBranchDecoderAlternative(aStateData);
break;
}
//
return(ret);
}
protected override void DecodePartial()
{
// According to Table 7-13, "Missing components of exception Branch address packets"
// then after a partial branch, we're always in "no exception" state
base.ExceptionType = TArmExceptionType.ENone;
// We have full 5 bytes of address info.
SymMask maskFirst = new SymMask(0x7E, SymMask.TShiftDirection.ERight, 1);
SymMask maskMiddle = new SymMask(0x7F);
SymByte b;
SymAddressWithKnownBits address = new SymAddressWithKnownBits();
uint masked = 0;
int count = base.Count;
// First byte
b = base[0];
address.KnownBits += 6;
address.Address |= maskFirst.Apply(b);
// Bytes 1, 2, 3
for (int i = 1; i < count; i++)
{
b = base[i];
b = (byte)maskMiddle.Apply(b);
masked = (uint)(b << address.KnownBits);
address.KnownBits += 7;
address.Address |= masked;
}
// Shift entire address by shift count based upon current instruction set.
int isShift = ETMBranchDecoder.CompressionLeftShiftCount(base.InstructionSet);
address.KnownBits += isShift;
address.Address <<= isShift;
// Save address
base.BranchAddress = address;
}
protected override void DecodeFull()
{
// We have full 5 bytes of address info.
SymMask maskFirst = new SymMask(0x7E, SymMask.TShiftDirection.ERight, 1);
SymMask maskMiddle = new SymMask(0x7F);
SymByte b;
SymAddressWithKnownBits address = new SymAddressWithKnownBits();
uint masked = 0;
// First byte
b = base[0];
address.KnownBits += 6;
address.Address |= maskFirst.Apply(b);
// Bytes 1, 2, 3
for (int i = 1; i <= 3; i++)
{
b = base[i];
b = (byte)maskMiddle.Apply(b);
masked = (uint)(b << address.KnownBits);
address.KnownBits += 7;
address.Address |= masked;
}
// Last byte - mask depends on instruction set.
b = base[4];
int lastByteAddressBits = 0;
if (this.ContainsInlineException || iMaskByte5_ARM.IsMatch(b))
{
// Inline exception indicates ARM.
base.InstructionSet = TArmInstructionSet.EARM;
lastByteAddressBits = 3;
}
else if (iMaskByte5_THUMB.IsMatch(b))
{
base.InstructionSet = TArmInstructionSet.ETHUMB;
lastByteAddressBits = 4;
}
else if (iMaskByte5_JAZELLE.IsMatch(b))
{
base.InstructionSet = TArmInstructionSet.EJAZELLE;
lastByteAddressBits = 5;
}
else
{
throw new ETMException("ERROR: branch type unknown");
}
// Now we can process the last byte
masked = b.LowestBits(lastByteAddressBits);
masked <<= address.KnownBits;
address.KnownBits += lastByteAddressBits;
address.Address |= masked;
// Shift entire address by shift count based upon current instruction set.
int isShift = ETMBranchDecoder.CompressionLeftShiftCount(base.InstructionSet);
System.Diagnostics.Debug.Assert(address.KnownBits + isShift == 32);
address.KnownBits = 32;
address.Address <<= isShift;
// Save address
base.BranchAddress = address;
// We may also need to decode the inline exception
if (ContainsInlineException)
{
// Yup, line exception...
DecodeInlineException(base.LastByte);
}
}