Startup

TODO: Preet to write content regarding startup, bss memory and data memory

Here are snippets of code the zero initialize the BSS and copy the DATA section from ROM to RAM.

static void startup__init_data_sram(void) {
  extern void *_bdata_lma;
  extern void *_bdata_vma;
  extern void *_data_end;

  uint8_t *src_flash = (uint8_t *)&_bdata_lma; // Flash
  uint8_t *dest_ram = (uint8_t *)&_bdata_vma;  // RAM
  while (dest_ram < (uint8_t *)&_data_end) {
    *dest_ram = *src_flash;
    dest_ram++;
    src_flash++;
  }
}

static void startup__init_bss_sram(void) {
  extern void *_bss_start;
  extern void *_bss_end;

  uint8_t *sram_ptr = (uint8_t *)&_bss_start;
  while (sram_ptr < (uint8_t *)&_bss_end) {
    *sram_ptr = 0U;
    sram_ptr++;
  }
}

Revision #3
Created 1 year ago by Preet Kang
Updated 3 months ago by Preet Kang