History of Null Pointer Dereferences on macOS

Re:History of Null Pointer Dereferences on macOS by DonHopkins on Friday March 21, 2025 @05:34AM (#43433591)

How things change! Page zero was extremely important on the Apple ][.

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Re:History of Null Pointer Dereferences on macOS by nomad41 on Friday March 21, 2025 @06:49AM (#43434095)

Very interesting. Can you expand on why? Or point to some relevant sources. Thank you in advance.

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Re:History of Null Pointer Dereferences on macOS by 0x0 on Friday March 21, 2025 @07:15AM (#43434279)

Probably because the 6502 CPU had instructions for optimized access to the zero page (first 256 bytes of RAM), this would also apply to C64 and NES etc. If you want to use "Indirect Indexed" memory accesses then I think it also has to go through an address held in the zero page.

See https://www.nesdev.org/obelisk-6502-guide/addressing.html

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Re:History of Null Pointer Dereferences on macOS by pajko on Friday March 21, 2025 @04:17PM (#43440352)

The AVR architecture puts its registers starting from address 0 of its data memory. As a twist, the program memory also starts at 0 (due to the Harvard architecture).

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