diff options
Diffstat (limited to 'ChocolArm64/Decoder/AOpCodeMemImm.cs')
| -rw-r--r-- | ChocolArm64/Decoder/AOpCodeMemImm.cs | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/ChocolArm64/Decoder/AOpCodeMemImm.cs b/ChocolArm64/Decoder/AOpCodeMemImm.cs new file mode 100644 index 00000000..14edc514 --- /dev/null +++ b/ChocolArm64/Decoder/AOpCodeMemImm.cs @@ -0,0 +1,53 @@ +using ChocolArm64.Instruction; + +namespace ChocolArm64.Decoder +{ + class AOpCodeMemImm : AOpCodeMem + { + public long Imm { get; protected set; } + public bool WBack { get; protected set; } + public bool PostIdx { get; protected set; } + protected bool Unscaled { get; private set; } + + private enum MemOp + { + Unscaled = 0, + PostIndexed = 1, + Unprivileged = 2, + PreIndexed = 3, + Unsigned + } + + public AOpCodeMemImm(AInst Inst, long Position, int OpCode) : base(Inst, Position, OpCode) + { + Extend64 = ((OpCode >> 22) & 3) == 2; + WBack = ((OpCode >> 24) & 1) == 0; + + //The type is not valid for the Unsigned Immediate 12-bits encoding, + //because the bits 11:10 are used for the larger Immediate offset. + MemOp Type = WBack ? (MemOp)((OpCode >> 10) & 3) : MemOp.Unsigned; + + PostIdx = Type == MemOp.PostIndexed; + Unscaled = Type == MemOp.Unscaled || + Type == MemOp.Unprivileged; + + //Unscaled and Unprivileged doesn't write back, + //but they do use the 9-bits Signed Immediate. + if (Unscaled) + { + WBack = false; + } + + if (WBack || Unscaled) + { + //9-bits Signed Immediate. + Imm = (OpCode << 43) >> 55; + } + else + { + //12-bits Unsigned Immediate. + Imm = ((OpCode >> 10) & 0xfff) << Size; + } + } + } +}
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