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.
- Remove XD bit in page tables
- Fix cylinder+head+sector arithmetic
- Implement fstat() for serial file descriptors on metal
Here's how to boot an Actually Portable Executable in QEMU:
make -j12 o//tool/viz/deathstar.com
qemu-system-x86_64 -serial stdio -fda o//tool/viz/deathstar.com
Here's a screenshot of DEATHSTAR.COM booted in QEMU:
https://justine.lol/cosmopolitan/cosmo-metal-qemu.png
Thus metal support is in much better shape now, but still incomplete.
Only a few system calls have been polyfilled. To figure out which ones
your program needs, simply boot it in the blinkenlights emulator with a
breakpoint, and press CTRL-C to continue to the system call breakpoint.
If it doesn't break then you should be good. (Note: to emulate normally
you can press 'c' and use CTRL-T and ALT-T to tune the speed.)
m=tiny
make -j12 SILENT=0 MODE=$m \
o/$m/tool/build/blinkenlights.com \
o/$m/tool/viz/deathstar.com
o/$m/tool/build/blinkenlights.com \
-r -t -b systemfive.linux \
o/$m/tool/viz/deathstar.com
Thank @Theldus for the bug report that made this change possible.
Fixes#20 which explains this change further.
blinkenlights now does a pretty good job emulating what happens when
binaries boot from BIOS into long mode. So it's been much easier to
debug the bare metal process and wrinkle out many issues.
