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bitread.py: fully parse type 1 and config packet length #53

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bitread.py: fully parse type 1 and config packet length #53

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56 changes: 47 additions & 9 deletions bitread.py
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Original file line number Diff line number Diff line change
Expand Up @@ -145,16 +145,37 @@ def find_config_packet(bitfile):
if bits_to_int(parse_word(bitfile)) == SYNC_WORD:
sync_word_found = True

in_config_data = False
in_config_data = False
type_2_fdri_write = False
packet_2_length = None

# Search for the start of the type 2 packet, which is where the configuration frames are
while not in_config_data:
word = parse_word(bitfile)
word = parse_word(bitfile)
# If type 2 packet header found, leave loop
if word[-3:] == [0, 1, 0]:
if word[-3:] == [0, 1, 0] and type_2_fdri_write:
packet_2_length = sum([b<<i for i, b in enumerate(word[:27])])
in_config_data = True
# Some other bitstream content
else:
# FDRI write not yet found
type_2_fdri_write = False

# If type 1 packet header found, parse packet
if word[-3:] == [1, 0, 0]:
packet_1_length = sum([b<<i for i, b in enumerate(word[:11])])
packet_1_addr = sum([b<<i for i, b in enumerate(word[13:27])])
packet_1_opcode = sum([b<<i for i, b in enumerate(word[27:29])])
packet_1_data = []
for i in range(packet_1_length):
packet_1_data.append(parse_word(bitfile))

# the typical FDRI write is a type-1 packet containing FDRI and length 0
# followed by a type-2 packet containing the configuration frames
type_2_fdri_write = packet_1_opcode == 2 and packet_1_addr == 2 and packet_1_length == 0

# We have read the bitstream up until the main configuration packet, exit the function
return part_name
return part_name, packet_2_length


def get_frame_list(part:str):
Expand Down Expand Up @@ -252,7 +273,7 @@ def get_frame_list(part:str):
return sorted(frames)


def parse_config_packet(bitfile, frames:list):
def parse_config_packet(bitfile, config_packet_length:int, frames:list):
'''
Parses the main configuration packet for all high bits
Arguments: The opened bitstream file and the list of frame addresses
Expand All @@ -262,6 +283,15 @@ def parse_config_packet(bitfile, frames:list):
# The number of words in a frame
FRAME_LENGTH = 101


# check if config packet is multiple of frame length
if config_packet_length % FRAME_LENGTH != 0:
print("ERROR: Config packet length must be multiple of frame length")
exit()

# frames remaining to be parsed
frames_remaining = config_packet_length

# List of high bits
bits = []
# Keep track of the previous frame so a row change can be detected
Expand All @@ -272,13 +302,16 @@ def parse_config_packet(bitfile, frames:list):

# Skip 2 frames worth of bits whenever the row changes
if prev_frame[1][17:23] != frame[1][17:23]:
frames_remaining -= FRAME_LENGTH*2
for i in range(FRAME_LENGTH*2):
parse_word(bitfile)

# Iterate for the number of words specified for this architecture's frame
for word_offset in range(FRAME_LENGTH):

frames_remaining -= 1
word = parse_word(bitfile)

# Iterate through each bit in the word
for bit_offset, bit in enumerate(word):
# The first 13 bits of the 51st word per frame are reserved for the "horizontal clock row" in series-7
Expand All @@ -291,7 +324,12 @@ def parse_config_packet(bitfile, frames:list):

prev_frame = frame.copy()

return bits
# now, only two dummy frames should remain to be read from the config packet
if frames_remaining != 2*FRAME_LENGTH:
print("ERROR: Config packet not fully parsed.")
exit()

return bits

##################################################
# Main Function #
Expand All @@ -307,8 +345,8 @@ def get_high_bits(bitstream:str):
# Begin reading the bitstream
with open(bitstream, "rb") as bitfile:

# Read through header and beginning parts of bitfile, get part name along the way
part = find_config_packet(bitfile)
# Read through header and beginning parts of bitfile, get part name and config packet length along the way
part, config_packet_length = find_config_packet(bitfile)

# Get a list of all the frames for the part. Each frame is a list with the hexadecimal
# and binary forms of the frame address for convenience.
Expand All @@ -319,7 +357,7 @@ def get_high_bits(bitstream:str):
exit()

# Parses the configuration packet and determines the addresses of high bits in the bitstream
bits = parse_config_packet(bitfile, frames)
bits = parse_config_packet(bitfile, config_packet_length, frames)

return bits

Expand Down