MajenkoProjects/sigrok-mfm
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Possible support for 7 byte headers

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This commit is contained in:
Matt Jenkins
2025-09-03 19:27:28 +01:00
parent 88afd6e282
commit 4b4c4e6f9b
1 changed files with 35 additions and 3 deletions
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38
mfm/pd.py
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@@ -113,6 +113,8 @@ class Decoder(srd.Decoder):
'default': 'HDD', 'values': ('FDD', 'HDD')},
{'id': 'sect_len', 'desc': 'Sector length',
'default': '512', 'values': ('128', '256', '512', '1024')},
{'id': 'header_bytes', 'desc': 'Header bytes',
'default': '8', 'values': ('7', '8')},
{'id': 'header_crc_bits', 'desc': 'Header field CRC bits',
'default': '16', 'values': ('16', '32')},
{'id': 'data_crc_bits', 'desc': 'Data field CRC bits',
@@ -159,6 +161,7 @@ class Decoder(srd.Decoder):
self.dsply_pfx = False # True = display all prefix bytes found, False = don't
self.dsply_sn = True # True = display sample number in window annotation, False = don't
self.header_crc_bytes = 2 # 16 or 32 bits for data field CRC/ECC
self.block_header_byte = 0 # Byte used to indicate the start of a block
self.data_crc_bytes = 4 # 16, 32 or 56 bits for data field CRC/ECC
self.samples30usec = 0 # number of samples in 30 usec.
@@ -246,6 +249,7 @@ class Decoder(srd.Decoder):
self.dsply_pfx = True if self.options['dsply_pfx'] == 'yes' else False
self.dsply_sn = True if self.options['dsply_sn'] == 'yes' else False
self.header_crc_bytes = int(self.options['header_crc_bits']) / 8
self.header_bytes = int(self.options['header_bytes'])
self.data_crc_bytes = int(self.options['data_crc_bits']) / 8
self.crc16_poly = int(self.options['crc16_poly'], 16)
self.crc32_poly = int(self.options['crc32_poly'], 16)
@@ -534,7 +538,34 @@ class Decoder(srd.Decoder):
# ------------------------------------------------------------------------
def decode_id_rec(self, fld_code, val):
if self.header_bytes == 7:
self.decode_id_rec_7byte(fld_code, val)
else:
self.decode_id_rec_8byte(fld_code,val)
def decode_id_rec_7byte(self, fld_code, val):
if fld_code == 3:
msb = self.block_header_byte ^ 0xFE
self.IDcyl = val | (msb << 8)
elif fld_code == 2:
self.IDsid = val & 0x0F
self.IDlenc = 512
if val & 0xF0 == 0:
self.IDlenv = 128
elif val & 0xF0 == 0x10:
self.IDlenv = 256
elif val & 0xF0 == 0x20:
self.IDlenv = 512
elif val & 0xF0 == 0x30:
self.IDlenv = 1024
else:
self.IDlenv = 0
if self.IDlenv != self.sector_len:
self.IDlastAM = -1
elif fld_code == 1:
self.IDsec = val
def decode_id_rec_8byte(self, fld_code, val):
if fld_code == 4:
self.IDcyl = val
elif fld_code == 3:
@@ -762,14 +793,15 @@ class Decoder(srd.Decoder):
return -1
elif self.pb_state == 6:
if val == 0xFE: # FEh ID Address Mark
if ((self.header_bytes == 8) and (val == 0xFE)) or ((self.header_bytes == 7) and ((val & 0xFC) == 0xFC)): # FEh ID Address Mark
self.display_byte(val, False)
self.crc(0xFE)
self.crc(val)
self.block_header_byte = val;
self.display_field('i')
self.IDlastAM = self.field_start
self.IDcrc = 0
self.pb_state = 7
self.byte_cnt = 4
self.byte_cnt = self.header_bytes - 4
elif val >= 0xF8 and val <= 0xFB: # F8h..FBh Data Address Mark
self.display_byte(val, False)
self.crc(val)