600行C编写RISC-V内核

eric2013

https://github.com/mnurzia/rv

用这个代码来学习RISC-V内核非常不错

rv-main.zip (13.29 KB)

支持的指令：

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#include <stdio.h>
#include <string.h>
 
#include "rv.h"
 
rv_res load_cb(void *user, rv_u32 addr, rv_u8 *data) {
  if (addr - 0x80000000 > 0x10000) /* Reset vector is 0x80000000 */
    return RV_BAD;
  *data = ((rv_u8 *)(user))[addr - 0x80000000];
  return RV_OK;
}
 
rv_res store_cb(void *user, rv_u32 addr, rv_u8 data) {
  if (addr - 0x80000000 > 0x10000)
    return RV_BAD;
  ((rv_u8 *)(user))[addr - 0x80000000] = data;
  return RV_OK;
}
 
rv_u32 program[2] = {
    /* _start: */
    0x02A88893, /* add a7, a7, 42 */
    0x00000073  /* ecall */
};
 
int main(void) {
  rv_u8 mem[0x10000];
  rv cpu;
  rv_init(&cpu, (void *)mem, &load_cb, &store_cb);
  memcpy((void *)mem, (void *)program, sizeof(program));
  while (rv_step(&cpu) != RV_EECALL) {
  }
  printf("Environment call @ %08X: %u\n", cpu.pc, cpu.r[17]);
  return 0;
}