The timers are on the 1MHz bus so there's a bunch of cycle stretching going on, plus there are 6502 bugs which cause spurious reads and writes (which normally don't matter.but if you spuriously write a timer you may reset it again.) To get some idea of the complexity bring up jsbeeb, hit HOME to pause it, then bring up the javascript console (usually ctrl-shift J) and type: KE's protection is _so_ much worse than Frogman too: it has interrupt handlers installed as well as using read-modify-write instructions to access the timers.
#Php javascript emulator update#
I'm hoping once we get it spot on we can write it up so others can update their emulators too. It's a giant pain to get it right - and thanks to Rich TW's help JSBeeb is *nearly* there. If you only tally up at the end of the instruction, then you'll come acropper with Frogman, not to mention all the Kevin Edwards protection systems (Alien8, Nightshare, Lunar Jetman). (It's still a bug that UK keyboards don't work all that well - I'm sorry and hope to work on that soon once I dig out my UK laptop and get things working fast enough on it to do some testing!)
![php javascript emulator php javascript emulator](https://3.bp.blogspot.com/-Lz7ZEVymmc4/XGk6RwSx5KI/AAAAAAAAO1E/zDatCwcriygjROZzqm_XerW7uB16UhUCACLcBGAs/s1600/CodeLobster%2BIDE.jpg)
I'm also glad to say Rich T-W is helping me with the more subtle timing issues - we hope that by the end of our efforts we'll have the most accurate emulator yet! I'm starting to notice more and more incompatibilities so will be working on some of the undocumented instructions. So for example you can now link to a bootable version of Repton. Very exciting as this means games can be played directly without messing about downloading and unzipping and whatnot!Īlso I've made the URLs shortcuttable - and although there's no button to do it yet, if you add "&autoboot" to the end of the URL it will automatically boot the game.
![php javascript emulator php javascript emulator](http://phpterm.sourceforge.net/img/browser.jpg)
An update: you can now load ZIP files directly into the emulator from the STH archives.