Merge pull request #1428 from ucb-bar/mt-hello

Add mt-helloworld example

tests/Makefile

@@ -29,7 +29,7 @@ include libgloss.mk
 
 PROGRAMS = pwm blkdev accum charcount nic-loopback big-blkdev pingd \
            streaming-passthrough streaming-fir nvdla spiflashread spiflashwrite fft gcd \
-           hello
+           hello mt-hello
 
 
 .DEFAULT_GOAL := default

tests/encoding.h

@@ -0,0 +1 @@
+../toolchains/riscv-tools/riscv-tests/env/encoding.h

tests/hello.c

@@ -1,6 +1,10 @@
 #include <stdio.h>
+#include "encoding.h"
+#include "marchid.h"
 
 int main(void) {
-  printf("Hello world\n");
+  uint64_t marchid = read_csr(marchid);
+  const char* march = get_march(marchid);
+  printf("Hello world from core 0, a %s\n", march);
   return 0;
 }

tests/marchid.h

@@ -0,0 +1,17 @@
+#ifndef MARCHID_H
+#define MARCHID_H
+
+const char* get_march(size_t marchid) {
+  switch (marchid) {
+  case 1:
+    return "rocket";
+  case 2:
+    return "sonicboom";
+  case 5:
+    return "spike";
+  default:
+    return "unknown";
+  }
+}
+
+#endif

tests/mt-hello.c

@@ -0,0 +1,48 @@
+#include "encoding.h"
+#include <stdio.h>
+#include "marchid.h"
+
+// EDIT THIS
+static size_t n_cores = 4;
+
+static void __attribute__((noinline)) barrier()
+{
+  static volatile int sense;
+  static volatile int count;
+  static __thread int threadsense;
+
+  __sync_synchronize();
+
+  threadsense = !threadsense;
+  if (__sync_fetch_and_add(&count, 1) == n_cores-1)
+  {
+    count = 0;
+    sense = threadsense;
+  }
+  else while(sense != threadsense)
+    ;
+
+  __sync_synchronize();
+}
+
+void __main(void) {
+  size_t mhartid = read_csr(mhartid);
+
+  if (mhartid >= n_cores) while (1);
+
+  const char* march = get_march(read_csr(marchid));
+  for (size_t i = 0; i < n_cores; i++) {
+    if (mhartid == i) {
+      printf("Hello world from core %lu, a %s\n", mhartid, march);
+    }
+    barrier();
+  }
+
+  // Spin if not core 0
+  if (mhartid > 0) while (1);
+}
+
+int main(void) {
+  __main();
+  return 0;
+}