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Code Issues Releases Wiki Activity

Investigating checksum algorithms

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This commit is contained in:
Ross Wilson
2016-02-03 19:46:55 +07:00
parent 685d049132
commit f5ed1a6b9c
1 changed files with 44 additions and 20 deletions
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64
idasm/check_sum.py
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@@ -8,20 +8,28 @@ Test code to determine the checksum algorithm used in Imlac PTP blocks.
MASK = 0177777
# actual block from 40tp_simpleDisplay.ptp
block = [065, # word count
0000100, # load address
0001012, 0102010, 0010101, 0002200, 0010103, 0001071, 0100041, 0044164, # data words
0020111, 0000000, 0004116, 0001003, 0003100, 0010101, 0015000, 0025000, # data words
0004005, 0006000, 0050132, 0050141, 0050151, 0050151, 0050156, 0015000, # data words
0025000, 0000000, 0030303, 0141702, 0114230, 0143707, 0143203, 0100770, # data words
0174171, 0030303, 0141702, 0154330, 0127655, 0174350, 0103605, 0154330, # data words
0074571, 0030303, 0141702, 0000600, 0154330, 0074571, 0030202, 0141723, # data words
0150327, 0143766, 0170362, 0074571, 0100000, # data words
0105226] # checksum word
block = [04, # word count
0007700, # load address
0001061, 0100011, 0023775, 0037765, # data words
0165054
]
#block = [065, # word count
# 0000100, # load address
# 0001012, 0102010, 0010101, 0002200, 0010103, 0001071, 0100041, 0044164, # data words
# 0020111, 0000000, 0004116, 0001003, 0003100, 0010101, 0015000, 0025000, # data words
# 0004005, 0006000, 0050132, 0050141, 0050151, 0050151, 0050156, 0015000, # data words
# 0025000, 0000000, 0030303, 0141702, 0114230, 0143707, 0143203, 0100770, # data words
# 0174171, 0030303, 0141702, 0154330, 0127655, 0174350, 0103605, 0154330, # data words
# 0074571, 0030303, 0141702, 0000600, 0154330, 0074571, 0030202, 0141723, # data words
# 0150327, 0143766, 0170362, 0074571, 0100000, # data words
# 0105226] # checksum word
def checksum1(block):
"""Checksum is sum of data words, mask at end."""
checksum1.tag = 'sum data, mask at end'
checksum = 0
for word in block[2:-1]:
checksum += word
@@ -30,6 +38,8 @@ def checksum1(block):
def checksum2(block):
"""Checksum is sum of data words, mask at each sum and end."""
checksum2.tag = 'sum data, mask each sum, mask at end'
checksum = 0
for word in block[2:-1]:
checksum = (checksum + word) & MASK
@@ -38,6 +48,8 @@ def checksum2(block):
def checksum3(block):
"""Checksum is sum of load address and data words, mask at end."""
checksum3.tag = 'sum loadaddr+data, mask at end'
checksum = block[1]
for word in block[2:-1]:
checksum += word
@@ -46,6 +58,8 @@ def checksum3(block):
def checksum4(block):
"""Checksum is sum of load address and data words, mask at each sum and end."""
checksum4.tag = 'sum loadaddr+data, mask each sum, mask at end'
checksum = block[1]
for word in block[2:-1]:
checksum = (checksum + word) & MASK
@@ -55,6 +69,8 @@ def checksum5(block):
"""Checksum is sum of word count, load address and data words,
mask at end."""
checksum5.tag = 'sum count+loadaddr+data, mask at end'
checksum = block[0]
checksum += block[1]
for word in block[2:-1]:
@@ -65,6 +81,8 @@ def checksum6(block):
"""Checksum is sum of word count, load address and data words,
mask at at each sum and end."""
checksum6.tag = 'sum count+loadaddr+data, mask each sum, mask at end'
checksum = block[0]
checksum = (checksum + block[1]) & MASK
for word in block[2:-1]:
@@ -74,6 +92,8 @@ def checksum6(block):
def checksum7(block):
"""Checksum is sum of data words, mask at end. Sum is +1 on overflow"""
checksum7.tag = 'sum data, +1 on sum overflow, mask at end'
checksum = 0
for word in block[2:-1]:
checksum += word
@@ -84,6 +104,8 @@ def checksum7(block):
def checksum8(block):
"""Checksum is sum of load + data words, mask at end. Sum is +1 on overflow"""
checksum8.tag = 'sum loadaddr+data, +1 on sum overflow, mask at end'
checksum = block[1]
for word in block[2:-1]:
checksum += word
@@ -94,6 +116,8 @@ def checksum8(block):
def checksum9(block):
"""Checksum is sum of count+load+data words, mask at end. Sum is +1 on overflow"""
checksum9.tag = 'sum count+loadaddr+data, +1 on sum overflow, mask at end'
checksum = block[0]
checksum += block[1]
if checksum & MASK:
@@ -114,14 +138,14 @@ csum7 = checksum7(block)
csum8 = checksum8(block)
csum9 = checksum9(block)
print('csum1=%06o' % csum1)
print('csum2=%06o' % csum2)
print('csum3=%06o' % csum3)
print('csum4=%06o' % csum4)
print('csum5=%06o' % csum5)
print('csum6=%06o' % csum6)
print('csum7=%06o' % csum7)
print('csum8=%06o' % csum8)
print('csum9=%06o' % csum9)
print('csum1=%06o, %s' % (csum1, checksum1.tag))
print('csum2=%06o, %s' % (csum2, checksum2.tag))
print('csum3=%06o, %s' % (csum3, checksum3.tag))
print('csum4=%06o, %s' % (csum4, checksum4.tag))
print('csum5=%06o, %s' % (csum5, checksum5.tag))
print('csum6=%06o, %s' % (csum6, checksum6.tag))
print('csum7=%06o, %s' % (csum7, checksum7.tag))
print('csum8=%06o, %s' % (csum8, checksum8.tag))
print('csum9=%06o, %s' % (csum9, checksum9.tag))
print('checksum should be 105226')
print('checksum should be %06o' % block[-1])