MOS 6502: 50 Years, Top 50 Instructions

The MOS 6502 microprocessor was released September 1975, and has now turned 50 years old. To celebrate, we’re counting down the top 50 instructions as ranked by use in possibly the most-executed 6502 software ever written: the built-in BASIC and KERNAL ROMs of the best-selling Commodore 64 home computer. We’ll also look at a bit of microprocessor history, another contender or two for software to examine, and give a real-world use for every single instruction, as found in the 16KB of ROM code in the C64. Happy birthday to the 6502 processor family!

Links:
Michael Steil’s Page Table Dot Com: https://www.pagetable.com/
C64 BASIC & KERNAL ROM Disassembly: https://www.pagetable.com/c64ref/c64disasm/
Talking Tech with Bill Mencsh: https://www.youtube.com/watch?v=sPaAnbkhgAE
How many C64s were sold: https://www.pagetable.com/?p=547
Dave McMurtrie’s take: https://commodore.international/2021/07/05/how-many-c64-and-c128-were-actually-sold/
Commodore Historical Documents: https://archive.org/details/commodorehistory?tab=collection&query=MOS
Using the MOS Microcomputers Programming Manual 2nd edition Jan. 1976: https://archive.org/details/mos_microcomputers_programming_manual
David Youd’s "EOR #$FF: 6502 Ponderables and Befuddlements": https://archive.org/details/eor6502

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Index:
0:00 A Brief History of the 6502
4:48 A top 50 list? Most-executed code? Method
11:31 #50-46 TXS, BVS, NOP, BVC, PHP
18:18 #45-41 PLP, CLI, SE, ROL, ROR
22:59 #40-36 LSR, ASL, BIT, CPY, INX
27:16 #35-31 TYA, DEX, TAY, CPX, DEY
31:37 #30-26 DEC, EOR, SEC, BMI, ORA
37:49 #25-21 TXA, INC, AND, TAX, SBC
43:38 #20-16 CLC, BPL, BCS, ADC, PHA
49:34 #15-11 INY, STX, PLA, BCC, STY
56:42 #10-6 RTS, CMP, LDX, BEQ, JMP
1:02:40 #5-2 Not telling
1:08:58 Special Extra Section
1:15:24 Revenge of CLV
1:20:08 The Number One
1:22:00 Mnemonic origin?
1:23:11 Thanks

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