cheaply print processors onto materials like plastic and paper

AnandTech: PlasticArm: Get Your Next CPU, Made Without Silicon (Dr. Ian Cutress)

Known for its core design IP that ends up in everything from IoT to smartphones to servers, Arm is now presenting that it has...

Known for its core design IP that ends up in everything from IoT to smartphones to servers, Arm is now presenting that it has enabled one of its key microcontrollers in a new form factor: rather than using silicon as a base, the company has enabled a processor core in plastic. The technology has been in the works for almost a decade, but Arm has...

justine.lol/ftrace/

The Cosmopolitan Libc _start() function starts by intercepting the --ftrace flag. If it exists, then it opens and sorts of the symbol table from the elf binary. Then it changes the protection of memory so it’s able to iterate over the program’s memory to look for nop instructions it can mutate. Those NOPs were inserted by GCC. It’s easy to self-modify them in memory, since they have the same byte length as the CALL instruction. Think of it like a mini linker. It just relinks the profiling nops. Once they’ve been rewritten, functions will start calling ftrace_hook() which is an assembly function that saves the CPU state to the stack. That means ftrace kind of acts like an operating system kernel. Once the assembly saved the CPU it can call the ftracer() C code that acquires a reentrant mutex and unwinds the RBP backtrace pointer (via __builtin_frame_address(0)) to determine the address of the function that called it. Once it has the address of the function, it passes it along to kprintf() which has a special %t syntax for turning numbers into symbols.

#c #investigation #programming #systems

youtube.com/watch?v=t_rzYnXEQl…

Recap of a lot of work, optimizing and rewriting code to squeeze out performance on limited hardware.

#gaming #gl #graphics #perf #programming #video #video

FIXING the ENTIRE SM64 Source Code (INSANE N64 performance)

Could this bring Luigi back?Patreon: https://www.patreon.com/Kazestuff🎥 https://www.twitch.tv/kazesm64🐦 https://twitter.com/KazeEmanuar

^YouTube

neilmadden.blog/2022/04/19/psy…

One side of the equation is r and the other side is multiplied by r and a value derived from s. So it would obviously be a really bad thing if r and s were both 0, because then you’d be checking that 0 = 0 ⨉ [a bunch of stuff], which will be true regardless of the value of [a bunch of stuff]! And that bunch of stuff is the important bits like the message and the public key. This is why the very first check in the ECDSA verification algorithm is to ensure that r and s are both >= 1.
Guess which check Java forgot?

#bugfix #crypto #java #security

CVE-2022-21449: Psychic Signatures in Java

The long-running BBC sci-fi show Doctor Who has a recurring plot device where the Doctor manages to get out of trouble by showing an identity card which is actually completely blank. Of course, thi…

^{Neil Madden}