We examine and improve a short machine language program to add hexadecimal number support to Commodore 64 BASIC, so you can POKE $D020,1. The original program is from Raeto Collin West's excellent "Programming the Commodore 64: The Definitive Guide". Supported by my patrons: http://patreon.com/8BitShowAndTell Link to .d64 file: http://8bitshowandtell.com/downloads/tmphex.d64 To use: LOAD"TMP",8,1 to load the assembler. SYS 32768 to start it. Back arrow (tilde in emulators) L to load. hex2 is the re-source of the original program, and hex8 is my modified program. Back arrow 3 to assemble, back arrow 1 to quit to BASIC, SYS 828 to start. Alternatively, LOAD"HEX2.O",8,1 or LOAD"HEX8.O",8,1 to load pre-assembled binaries of either version, SYS 828 to start. Links: Programming the Commodore 64: https://ia800905.us.archive.org/30/items/Compute_s_Programming_the_Commodore_64_The_Definitive_Guide/Compute_s_Programming_the_Commodore_64_The_Definitive_Guide.pdf Mapping the C64 on archive.org: https://archive.org/details/Compute_s_Mapping_the_64_and_64C/ Commodore 64 Programmer's Reference Guide: https://archive.org/details/c64-programmer-ref/ Good information about the C64 floating point math routines: https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics Index: 0:00 Programming The Commodore 64, page 268 0:45 The BASIC listing: adding hex support 2:57 Examining my re-sourced version. File: hex2 6:23 A quick look at CHRGET ($0073) 8:04 Converting the ASCII hex string 10:09 A needed clarification 15:10 Returning the value to BASIC 19:05 Adding 8-bit support. File: hex7 20:46 A quick look at CHRGOT ($0079) 24:56 Testing the 8-bit hex support 26:40 Thanks to my patrons