Hi,
I want to know whether the following SRAM is the scratchpad memory:
If it is, how to use it by programming?
I noticed the reply,
but I am confused, does it mean any vector load instruction would access data via scratchpad memory naturally? If so, it sounds not like scratchpad memory, because it should be controlled by programmer, right?
Thank you in advance.
Best,
Related post: 如何利用K1开发板的TCM缓存 - K1 - 进迭RISC-V论坛
我也有这个问题，根据我查到的资料：
#include <stdio.h>
#include <stdint.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#define TCM_PHYS 0xd8000000UL
#define TCM_SIZE 0x20000
int main() {
printf("Opening /dev/mem...\n");
int fd = open("/dev/mem", O_RDWR | O_SYNC);
if (fd < 0) {
perror("open /dev/mem");
return 1;
}
printf("Mapping TCM phys 0x%lx...\n", TCM_PHYS);
void *va = mmap(NULL, TCM_SIZE, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, TCM_PHYS);
if (va == MAP_FAILED) {
perror("mmap TCM");
close(fd);
return 1;
}
printf("TCM VA = %p\n", va);
volatile uint32_t *p = (volatile uint32_t *)va;
printf("Writing 0x12345678 to TCM...\n");
p[0] = 0x12345678; // <-- 关键测试点
printf("Reading back...\n");
uint32_t v = p[0];
printf("TCM[0] = 0x%08x\n", v);
munmap(va, TCM_SIZE);
close(fd);
return 0;
}
然后这是运行结果：
