More sensible get_bits() implementation

This commit is contained in:
CPunch 2021-04-11 18:47:59 -05:00
parent 88d669f3c8
commit 74dfb5f241
1 changed files with 6 additions and 6 deletions

12
luac.py
View File

@ -39,8 +39,8 @@ def get_bits(num, p, k):
for i in range(32 - len(binary)): for i in range(32 - len(binary)):
binary = '0' + binary binary = '0' + binary
end = len(binary) - p + 1 end = len(binary) - p
start = len(binary) - k + 1 start = len(binary) - k
# extract k bit sub-string # extract k bit sub-string
kBitSubStr = binary[start : end] kBitSubStr = binary[start : end]
@ -151,7 +151,7 @@ class LuaUndump:
} }
data = self.get_int32() data = self.get_int32()
opcode = get_bits(data, 1, 6) opcode = get_bits(data, 0, 6)
tp = lua_opcode_types[opcode] tp = lua_opcode_types[opcode]
instruction['OPCODE'] = opcode instruction['OPCODE'] = opcode
@ -159,12 +159,12 @@ class LuaUndump:
instruction['A'] = get_bits(data, 7, 14) instruction['A'] = get_bits(data, 7, 14)
if instruction['TYPE'] == "ABC": if instruction['TYPE'] == "ABC":
instruction['B'] = get_bits(data, 24, 32) instruction['B'] = get_bits(data, 24, 31)
instruction['C'] = get_bits(data, 15, 23) instruction['C'] = get_bits(data, 15, 23)
elif instruction['TYPE'] == "ABx": elif instruction['TYPE'] == "ABx":
instruction['Bx'] = get_bits(data, 15, 32) instruction['Bx'] = get_bits(data, 15, 31)
elif instruction['TYPE'] == "AsBx": elif instruction['TYPE'] == "AsBx":
instruction['sBx'] = get_bits(data, 15, 32) - 131071 instruction['sBx'] = get_bits(data, 15, 31) - 131071
chunk['INSTRUCTIONS'][i] = instruction chunk['INSTRUCTIONS'][i] = instruction