18 lines
941 B
Plaintext
18 lines
941 B
Plaintext
CLI + JMP ($A000) + LDX #$xx
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The C64 programmer's reference guide explains that the KERNAL
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clears interrupts and jumps into the cold start vector of
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the BASIC ROM on boot. This is exactly what this snippet does,
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and it is the most obvious solution. Also, it is well established
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best practice to disable interrupt masking only at the last moment
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to minimise the risk of an interrupt being triggered before the
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called program has a chance to setup what it wants.
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The presence of the LDX #$xx following this is the result of the
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mechanical processes of our linker, and is mere coincidence. As
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this opcode constitutes >1% of opcodes in a typical 6502 program,
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no reasonable claim can be made based on its presence.
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In short, this fragment is the obvious and most simple implementation
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that implements the described functionality p269 of the C64 PRG, as
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well as being too short and lacking creativity to be eligible for
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copyright protection.
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