There were a few issues that were causing qemu-system-arm and
qemu-system-riscv to give the wrong exit codes. They are in fact capable
of exiting with 0 or 1 signalled from the running application, but this
functionality wasn't used. This commit changes this in the following
ways:
* It fixes SemiHosting codes, which were incorrectly written in
decimal while they should have been written in hexadecimal (oops!).
* It modifies all the baremetal main functions (aka reset handlers) to
exit with `exit(0)` instead of `abort()`.
* It changes `syscall.Exit` to call `exit(code)` instead of `abort()`
on baremetal targets.
* It adds these new exit functions where necessary, implemented in a
way that signals the correct exit status if running under QEMU.
All in all, this means that `tinygo test` doesn't have to look at the
output of a test to determine the outcome. It can simply look at the
exit code.
This change adds support for the ESP32-C3, a new chip from Espressif. It
is a RISC-V core so porting was comparatively easy.
Most peripherals are shared with the (original) ESP32 chip, but with
subtle differences. Also, the SVD file I've used gives some
peripherals/registers a different name which makes sharing code harder.
Eventually, when an official SVD file for the ESP32 is released, I
expect that a lot of code can be shared between the two chips.
More information: https://www.espressif.com/en/products/socs/esp32-c3
TODO:
- stack scheduler
- interrupts
- most peripherals (SPI, I2C, PWM, etc)