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parseinstrs: Generalize immediate size computation

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This commit is contained in:
Alexis Engelke
2021-01-22 11:08:04 +01:00
parent 62018556a1
commit 801fe4bc43
1 changed files with 14 additions and 15 deletions
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29
parseinstrs.py
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@@ -124,6 +124,17 @@ class InstrDesc(NamedTuple):
operands = tuple(OpKind.parse(op) for op in desc[1:5] if op != "-")
return cls(desc[5], desc[0], operands, frozenset(desc[6:]))
def imm_size(self, opsz):
flags = ENCODINGS[self.encoding]
if flags.imm_control < 4:
return 0
if self.mnemonic == "ENTER":
return 3
if "IMM_8" in self.flags:
return 1
max_imm_size = 4 if self.mnemonic != "MOVABS" else 8
return min(max_imm_size, self.operands[flags.imm_idx^3].abssize(opsz))
def encode(self, ign66, modrm):
flags = ENCODINGS[self.encoding]
extraflags = {}
@@ -159,11 +170,8 @@ class InstrDesc(NamedTuple):
if "USE66" not in self.flags and (ign66 or "IGN66" in self.flags):
extraflags["ign66"] = 1
if flags.imm_control >= 4:
imm_op = self.operands[flags.imm_idx^3]
if ("IMM_8" in self.flags or imm_op.size == 1 or
(imm_op.size == OpKind.SZ_OP and "SIZE_8" in self.flags)):
extraflags["imm_control"] = flags.imm_control | 1
if self.imm_size(1 if "SIZE_8" in self.flags else 8) == 1:
extraflags["imm_control"] = flags.imm_control | 1
enc = flags._replace(**extraflags)._encode()
enc = tuple((enc >> i) & 0xffff for i in range(0, 48, 16))
@@ -538,16 +546,7 @@ def encode_table(entries):
if prefix[1] == "|OPC_LOCK" and ots[0] != "m":
continue
imm_size = 0
if enc.imm_control >= 4:
if desc.mnemonic == "ENTER":
imm_size = 3
elif "IMM_8" in desc.flags:
imm_size = 1
else:
max_imm_size = 4 if desc.mnemonic != "MOVABS" else 8
imm_opsize = desc.operands[enc.imm_idx^3].abssize(opsize//8)
imm_size = min(max_imm_size, imm_opsize)
imm_size = desc.imm_size(opsize//8)
tys = [] # operands that require special handling
for ot, op in zip(ots, desc.operands):