commit 741fd92fecf44854f984a8b2a55bebfae2e5a59f parent e254b0de3432fdbf3b9c20f36537442cfc56c4f0 Author: Brian Swetland <swetland@frotz.net> Date: Thu, 18 Aug 2022 23:13:36 -0700 add readme to provide some context Diffstat:
| A | README.txt | | | 32 | ++++++++++++++++++++++++++++++++ |
1 file changed, 32 insertions(+), 0 deletions(-)
diff --git a/README.txt b/README.txt @@ -0,0 +1,32 @@ + +This is Z80 assembly source for the ZX81 ROM. + +This version came from this URL -- I cannot find the author or more context: +https://cdn.hackaday.io/files/289631239152992/ZX81_dual_2018-02-09.htm + +This repository tracks the original as I tidied it up to build under z80asm +and will track any further cleanup I do. + + +It appears to be derived from this version (dated 13-DEC-2004): + +https://www.tablix.org/~avian/spectrum/rom/ +https://www.tablix.org/~avian/spectrum/rom/zx81.htm + +"These files were originally hosted at www.wearmouth.demon.co.uk and +maintained by Geoff Wearmouth. Unfortunately that website went off-line +sometime around the end of 2015 and as of 2017 no copies were available +for the casual reader. To keep this valuable historical resource available, +some files from that website have been preserved here. Files hosted on +this website are from a snapshot captured on 1 September 2015. They were +not modified, except for this index page, which was copy-edited for +readability." + +The original files are archived in the mirror/ subdirectory for reference. + + +The hackaday hosted version folds together the original and "shoulders of +giants" (enhanced) rom sources with conditional build directives, but more +importantly uses descriptive labels like LIST-TOP instead of address-based +labels like L0433 which the original rom listing does. +