Средства и методы разработки

link.ld

SECTIONS
{
  .init :
  {
    _sinit = .;
    . = ALIGN(4);
    LONG((_start << 20) | 0x6f) /* encode 'j _start' instruction, must be below 2K */
    KEEP(*(.init.vectors))
    KEEP(*(.init))
    . = ALIGN(4);
    _einit = .;
  } >FLASH AT>FLASH
  .text :
  {

startup.c

#include "ch32v00x.h"
#include <string.h>

static void
trap(void)
{
    int volatile w = 1;
    while (w) ;
}

void __attribute__((naked, section(".init")))
_start(void)
{
    extern int main(void);
    __asm volatile(
        "   j     3f                \n\t"
        "1: .word __global_pointer$ \n\t" // literal pool of two constants
        "2: .word _eusrstack        \n\t" // keeps compiler from replacing them with registers
        "3: lw    gp, 1b            \n\t" // load gp
        "   lw    sp, 2b            \n\t" // load sp
        "   li    t0, 0x80          \n\t"
        "   csrw  mstatus, t0       \n\t"
        "   csrwi 0x804, 3          \n\t"
        "   csrwi mtvec, 3          \n\t"
        "   la    t0, main          \n\t"
        "   csrw  mepc, t0          \n\t");
    extern char _data_lma[], _data_vma[], _edata[];
    memcpy(_data_vma, _data_lma, _edata - _data_vma);
    extern char _sbss[], _ebss[];
    memset(_sbss, 0, _ebss - _sbss);
    main();
}

extern void SysTick_Handler(void);
extern void adc_handler(void);

static void (*const vectab[])(void) __attribute__((used, section(".init.vectors"))) = {
    [-1 + NonMaskableInt_IRQn] = trap,
    [-1 + HardFault_IRQn     ] = trap,
    [-1 + SysTick_IRQn       ] = SysTick_Handler,
    [-1 + ADC_IRQn           ] = adc_handler,
};