How ARM64 uses its special SIMD registers in lanes, and how they can be loaded with and without de-interleaving.
assembler
Details options available for rounding floating point numbers, and all the scalar floating point operations. There’s another cheat sheet summary too.
Floating point numbers are very different from integers, but are loaded and stored much the same. Conversion between registers, including to and from integers, is complex.
Where code can make simple selections according to a conditional test, it may be possible to eliminate branching and ensure rapid execution.
An overview of bit operations, including MOVK for 16-bit immediate values, bit shift operations, bitwise AND, OR, XOR, and more, plus a cheat sheet.
Basic integer arithmetic – add, subtract, negate, multiply, multiply-and-add, and divide – in their many variations. With some catches for those more used to high-level languages.
Explaining the LDR family of instructions for loading registers, MOV for moving one register to another, STR for storing to memory, and SXTx/UXTx for filling a register with smaller data types.
How conditional branching can slow modern processors down badly, comparing assembly code with that generated by Apple’s Swift compiler, and some puzzles.
How to implement conditional looping such as for and while, and how to break out of a loop. Complete with chart of four conditional idioms.
How little has changed in using assembly language over the last 30+ years. But what about Swift Playgrounds 4, which will let iPads create apps for the App Store?
The Eclectic Light Company 