Support variable flash and RAM start addresses and sizes.

[david-perez]

Previously, only variable flash start address was supported via the FLASH_START cmake variable (see commit 2d9a530).

Commit 160991c introduced a partial regression in accidentally removing support for variable flash start addresses. This commit fixes that, while in addition introducing support for variable flash size, RAM start address and RAM size.

Fixes #9.

[david-perez]

For future reference, I used find . -type f -name "*.ld" -exec sed -i -r '/MEMORY/ { n; n; s/(ORIGIN = )(.*), (LENGTH = )(.*)/\1DEFINED(flash_origin) ? flash_origin : \2, \3DEFINED(flash_length) ? flash_length : \4/; n; s/(ORIGIN = )(.*), (LENGTH = )(.*)/\1DEFINED(ram_origin) ? ram_origin : \2, \3DEFINED(ram_length) ? ram_length : \4/; }' {} + to change the linker scripts from the device/ folder.

[david-perez]

I fixed the last assertion in the linker script that checks that flash memory doesn't overflow, since now programs may not necessarily start at 0x0.

For future reference, this time I used find . -type f -name "*.ld" -exec sed -i -r 's/(>= \(__etext)/\1 - ORIGIN\(FLASH\)/' {} + from the device/ folder.

[ryankurte]

looks awesome, thanks!

are you able to refactor against master to sort out those conflicts, then we can merge this in?

[david-perez]

That should do it.