edd9297eba
Your Actually Portable Executables now contains a simple virtual memory that works similarly to the Linux Kernel in the sense that it maps your physical memory to negative addresses. This is needed to support mmap() and malloc(). This functionality has zero code size impact. For example the MODE=tiny LIFE.COM executable is still only 12KB in size. The APE bootloader code has also been simplified to improve readibility and further elevate the elegance by which we're able to support so many platforms thereby enhancing verifiability so that we may engender trust in this bootloading process.
SYNOPSIS
System Five Import Libraries
OVERVIEW
Bell System Five is the umbrella term we use to describe Linux, FreeBSD, OpenBSD, and Mac OS X which all have nearly-identical application binary interfaces that stood the test of time, having definitions nearly the same as those of AT&T back in the 1980's.
Cosmopolitan aims to help you build apps that can endure over the course of decades, just like these systems have: without needing to lift a finger for maintenance churn, broken builds, broken hearts.
The challenge to System V binary compatibility basically boils down to numbers. All these systems agree on what services are provided, but tend to grant them wildly different numbers.
We address this by putting all the numbers in a couple big shell scripts, ask the GNU Assembler to encode them into binaries using an efficient LEB128 encoding, unpacked by _init(), and ref'd via extern const. It gives us good debuggability, and any costs are gained back by fewer branches in wrapper functions.z