if you don't have anything interesting to say in a comment, at least it should be fun. https://v.st/~th/llander/#79c2
Timeline
Post
Remote status
Context
3Now with inline SVG rendering of fonts and line artwork using my Atari Digital Vector Generator emulator. https://v.st/~th/llander/#7838
Is it just me or is the 6502 CMP instruction's handling of the carry flag backwards?
(I know it has to do with the way SBC deals with carry, but it just feels wrong to me, so I needed to write myself a cheat sheet)
somehow I got 25% of the way disassembling and commenting on Atari's Lunar Lander ROM before finding that Rich Moore's original 1978 macro assembler source is available. https://github.com/historicalsource/lunar-lander/blob/main/A34573.1A
Replies
3My function name: check_coin_inserted
Their original name: MOOLAH
#RetroComputing
Any ideas what the "^H" syntax means in this 6502 macro assembler? The file .RADIX is 16, so all the values are already in hex and the other constants don't use this prefix.
(Also there's a 40 year old typo that the ROM address is commented as "VG RAM")
Was Atari assembling their arcade games on an PDP-11 MACRO-11 inspired system? It seems that they use a unary ^ to switch bases or apply ones complement a value, along with the ".TITLE", ".SBTTL" and ".PAGE" directives, although DEC used ^X for hex not ^H. https://www.bitsavers.org/pdf/dec/pdp11/ias/v3.4/AA-KX10A-TC_PDP-11_MACRO-11_Language_Reference_Manual_198805.pdf