ESP32 ulp - can mos compile .S assembler files?

General
#21

I am not sure how to export everythink into libulp.a . I found one part of the missing symbols in the following ESP-IDF file ulp_main.ld:

/* Variable definitions for ESP32ULP linker
*This file is generated automatically by esp32ulp_mapgen.py utility.
*/

PROVIDE ( ulp_changed = 0x50000054 );
PROVIDE ( ulp_debounce_counter = 0x500000d0 );
PROVIDE ( ulp_debounce_max_count = 0x500000d4 );
PROVIDE ( ulp_edge_count = 0x500000d8 );
PROVIDE ( ulp_edge_count_to_wake_up = 0x500000dc );
PROVIDE ( ulp_edge_detected = 0x50000070 );
PROVIDE ( ulp_entry = 0x50000000 );
PROVIDE ( ulp_io_number = 0x500000e0 );
PROVIDE ( ulp_next_edge = 0x500000cc );
PROVIDE ( ulp_wake_up = 0x500000b8 );

And the other part of it in ulp-example.map:

.rodata.embedded
                0x3f402d65       0xd8 C:/msys32/home/name/esp/ulp/build/main\libmain.a(ulp_main.bin.bin.o)
                0x3f402d65                _binary_ulp_main_bin_start
                0x3f402e3d                _binary_ulp_main_bin_end
#22

OK, so the linker script provides the missing symbols.
Since mongoose os build command does not use that linker script, you need to move those symbols manually into your .c file. Example:

uint32_t *ulp_debounce_counter_pointer = (uint32_t *) 0x500000d0;
...

So instead of only declaring them, define the pointers, and use pointers in your code. Maybe there is a cleaner way without the pointers, but that’s something that first comes to mind.