Nybbles and MouseBytes: Ep3: Comparison Instructions
Nybbles and Bytes
Let's talk about the 8502's comparison instructions! These little instructions are somewhat tricky at first glance, but once you get to using them, it's much simpler. Let's build a program that draws raster bars!
Help me cover my costs on Patreon: https://www.patreon.com/nybblesandbytes
Follow along and fill in your gaps with these manuals:
Assembly in One Step by RTK: https://dwheeler.com/6502/oneelkruns/asm1step.html Matt Godbolt's Blog on 6502 internals: https://xania.org/201405/jsbeeb-getting-the-timings-right-cpu My 6502 Instruction Reference: http://nybblesandbytes.net/6502 Skilldrick's Easy6502: http://skilldrick.github.io/easy6502
Indexes: 0:24 - CMP behavior description 1:08 - CMP chart and addressing modes 1:20 - CPX chart and addressing modes 1:38 - CPY chart and addressing modes 1:50 - Raster bar program description 2:17 - Raster bar program explanation 3:18 - Raster bar program execution
Don't have a 128 to play on? Use an emulator like the VICE x128 emulator here: http://vice-emu.sourceforge.net
The music used in the video were songs by Jeremy Blake, specifically Let's Go Home. They're available free on YouTube. ... https://www.youtube.com/watch?v=8Cp9aBzZ9NM
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