hello_world/hello_world.c

   1 #include <stdint.h>
   2 #include <stdbool.h>
   3
   4 #include "console.h"
   5
   6 static char mw_logo[] =
   7
   8 "\n"
   9 "   .oOOo.     \n"
  10 " .\"      \". \n"
  11 " ;  .mw.  ;   Microwatt, it works.\n"
  12 "  . '  ' .    \n"
  13 "   \\ || /    \n"
  14 "    ;..;      \n"
  15 "    ;..;      \n"
  16 "    `ww'   \n";
  17
  18 static inline uint32_t readl(unsigned long addr)
  19 {
  20     uint32_t val;
  21     __asm__ volatile("sync; lwzcix %0,0,%1" : "=r" (val) : "r" (addr) : "memory");
  22     return val;
  23 }
  24
  25 static inline void writel(uint32_t val, unsigned long addr)
  26 {
  27     __asm__ volatile("sync; stwcix %0,0,%1" : : "r" (val), "r" (addr) : "memory");
  28 }
  29
  30 void uart_writeuint32(uint32_t val) {
  31     const char lut[] = { '0', '1', '2', '3', '4', '5', '6', '7',
  32                          '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
  33     uint8_t *val_arr = (uint8_t*)(&val);
  34     size_t i;
  35
  36     for (i = 0; i < 4; i++) {
  37         putchar(lut[(val_arr[3-i] >> 4) & 0xF]);
  38         putchar(lut[val_arr[3-i] & 0xF]);
  39     }
  40 }
  41
  42
  43 int main(void)
  44 {
  45         console_init();
  46
  47         puts(mw_logo);
  48
  49     volatile uint32_t *sram = 0x0;
  50     int count = 26;
  51         puts("writing\n");
  52     for (int i = 0; i < count; i++) {
  53         uart_writeuint32(i);
  54         puts("\n");
  55         writel(0xBEEF0000+i, &(sram[1<<i]));
  56     }
  57         puts("reading\n");
  58     for (int i = 0; i < count; i++) {
  59         int val = readl(&(sram[1<<i]));
  60         uart_writeuint32(i);
  61         puts(" ");
  62         uart_writeuint32(val);
  63         puts("\n");
  64     }
  65         while (1) {
  66                 unsigned char c = getchar();
  67                 putchar(c);
  68                 if (c == 13) // if CR send LF
  69                         putchar(10);
  70         }
  71 }