Adding Hex Support To C64 BASIC

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".

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Link to .d64 file: http://8bitshowandtell.com/downloads/...

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:NEW to start.

Links:
Programming the Commodore 64: https://ia800905.us.archive.org/30/it...
Mapping the C64 on archive.org: https://archive.org/details/Compute_s...
Commodore 64 Programmer's Reference Guide: https://archive.org/details/c64-progr...
Good information about the C64 floating point math routines: https://codebase64.org/doku.php?id=ba...

Ending credits music is "64738" by Bedford Level Experiment:    • 64738 - Lyric Video  

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)
26:10 Testing the 8-bit hex support
27:55 Thanks to my patrons

#Commodore64 #Hexadecimal