alt Hacker NewsI don't always make 6502(ish) errors, but when i do, it's usually the memory address instead of the immediate! It's a very common and easy mistake to make, and i believe Chuck Peddle himself deeply regretted the (number symbol, pound sign, hashtag) #$1234 syntax for immediate values. I made # appear bright red in my IDE, it helps, a bit... Even the ASM gods at Rare fell victim to the same issue!
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I ran into a similar issue a long time ago, with the GNU assembler in "intel_syntax noprefix" mode. It has an issue where there's syntactic ambiguity that makes it possible to interpret a forward-referenced named constant immediate as a reference to an unknown symbol, if in an instruction that could accept either an immediate or a memory address. The net result is assembling the instruction to have a placeholder memory address (expected to be filled in by the relocated address of the symbol when linked) rather than the expected immediate. Painful to debug.
Instructions sets like ARM basically made it impossible to make that mistake. You need to use a different instructions when you involve memory.