IEEE 754 standard - converting 64 bit hex to decimal

General Discussion
1

Did anyone attempt to convert ieee 754 (64 bit double-precision floating-point ) hex to float using python in Ignition. What are the ways of doing it?

Thanks.

1 Like
2

Give this a go:

import struct

# Convert IEEE 754 64-bit Hex to Float
hexString="4002c3c9eecbfb16"
print struct.unpack("d", struct.pack("Q",int("0x"+hexString, 16)))[0]

# Convert IEEE 754 64-bit Float to Hex
decVal=2.3456
print hex(struct.unpack("Q", struct.pack("d",decVal))[0])


3

Does it do it from right to left or left to right?

4

EDIT: Cleaned up post after migration. :slight_smile:

Left-to-right (big-endian, which is my system default). If you need to specify endianness:

big-endian:

import struct

# Convert IEEE 754 64-bit Hex to Float
hexString="4002c3c9eecbfb16"
print struct.unpack(">d", struct.pack("Q",int("0x"+hexString, 16)))[0]

# Convert IEEE 754 64-bit Float to Hex
decVal=2.3456
print hex(struct.unpack(">Q", struct.pack("d",decVal))[0])

little-endian:

import struct

# Convert IEEE 754 64-bit Hex to Float
hexString="4002c3c9eecbfb16"
print struct.unpack("<d", struct.pack("Q",int("0x"+hexString, 16)))[0]

# Convert IEEE 754 64-bit Float to Hex
decVal=2.3456
print hex(struct.unpack("<Q", struct.pack("d",decVal))[0])

Checked via online converter:
http://babbage.cs.qc.cuny.edu/IEEE-754/

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