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Convert hex byte to decimal equivale

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djsorgan
Converser

Posts: 13

Convert hex byte to decimal equivale Aug 15, 2023 1:45:53 GMT

Quote

Post by djsorgan on Aug 15, 2023 1:45:53 GMT

Is there an easy way to convert a hex byte (00 to 7F) to a decimal value (0 to 127) in Stream Byter? I am controlling the tempo of the Dynamic Clock. It requires a Sysex with decimal values (F0 5A I0 I1 I2 F7). My remote input is in Hex. How can I convert the input hex to a decimal value?

A formula that works is Decimal Value = (MSB * 128) + LSBd. I know how to convert this to the required Dynamic Clock Tempo input.

For example, if the input is F0 58 08 01 7E F7 (tempo = 254), the input to the Dynamic Clock is F0 5A 02 54 00 F7. The issue is converting the 5th byte (7E) to a decimal for the LSB in the above formula. Is there an easy formula or must a 128 element array be created to use as a lookup? Can the array be implemented using elements represented in hex with data being the decimal. For example ... L7D ==> 125, L7E ==> 126, L7F ==> 127.

For the above example, the formula is: Decimal Value = (1 * 128) + 126 = 254, where LSB 7Eh ==> 126d

redheronmusic
Oracle

Posts: 65

Convert hex byte to decimal equivale Aug 16, 2023 15:32:22 GMT

Quote

Post by redheronmusic on Aug 16, 2023 15:32:22 GMT

This should be posted in the StreamByter section as more appropriate to your question.

For ease of testing, this code is configured to use the SB interface to enter numbers and see the pseudo BCD conversion. For production use, grab the code from BEGIN to END.

# Red Heron Music
# Aug 16, 2023
# Covert 2 x 7 byte hex values (eg MIDI Bytes) to pseudo BCD values
# max valid input value is 9999 or 4E 0F (have to add third output byte to represent higher inputs)

# configured to use Q0, Q1 as inputs, results shown in LB0, LB1
# Input controls are in hex (displayed as decimal)
# output is hex

# pseudo BCD logic is fairly simple
# divide & mod by 100 to split MSB / LSB
# if digit value is between
#   11 and 19, you have to add six to the hex value
#   20 - 29, add 12
#   etc

# for production use, you want the code from BEGIN to END

# i0 is total input value
# i1 is base 10 MSB
# i2 is base 10 LSB
# i3 is MSB pseudo BCD
# i4 is LSB pseudo BCD

If load
	Set Q0 MSB
	Set Q1 LSB
	Set LB0 0
	Set LB1 0
	Ass Q0 = 0 0
End

IF M0 == F0 7D 01
	# BEGIN
	Mat i0 = Q0 * $128 
	Mat i0 = i0 + Q1 ‘ i0 now is total value
	Mat i1 = i0 / $100 ‘ get MSB
	Mat i2 = i0 % $100 ‘ remainder

# Convert MSB to pseudo BCD
	Mat i3 = i1 / $10
	Mat i3 = i3 * 6
	Mat i1 = i1 + i3

# Covert LSB to pseudo BCD
	Mat i4 = i2 / $10
	Mat i4 = i4 * 6
	Mat i2 = i2 + i4
	# END	

	Set LB0 i1
	Set LB1 i2
End

Last Edit: Aug 16, 2023 15:39:59 GMT by redheronmusic