convert decimal to hex with 3 digit

I just realized that converting -30 to hexadecial by dec2hex(-30) is different from its converting back by hex2dec('E2'). Any suggestion donig right?

dec2hex(-30)

ans = 'E2'

hex2dec('E2')

ans = 226

Also if I want to specify the decimal in signed 12 bit (e.g., 3 hex digital), what am I supposed to do?

Answer 1

[Chunru]

dec2hex(-30)            % this converts to hex in 2's complement

ans = 'E2'

hex2dec('E2')           % this treats the hex as unsigned by default

ans = 226

hex2dec('0xE2s8')       % s8 to indicate the hex is a signed 8 bit nmber; 0x prefix is also needed

ans = -30

[Jay]

Thanks a lot! This partially resolve my issues. What am I supposed to do if I convert a signed 12-bit to hexadecimal number or vice versa?

To be more specific, my problem is follow.

I have list of decimal number which can be represented by signed 12-bit. Simply converting them using dec2hex gives various word lengths (e.g., 2 or 3 hex digits some time and 4 hex digits for some negative numbers). Any way to convert to 3-hex digit which is corresponding to signed 12 bits? Otherwise, the indication of the signed bit width in your solution (e.g., hex2dec('0xE2s8') only for partially and 3 or 4 hex digit numbers have to be processed separately.

[Stephen23]

dec2hex(-30,4)

ans = 'FFE2'

hex2dec('0xFFE2s16')

ans = -30