regalloc: start implementing linear scan

1 files changed, 29 insertions, 0 deletions

diff --git a/test/collatz.c b/test/collatz.c
new file mode 100644
index 0000000..9793594
--- /dev/null
+++ b/test/collatz.c
@@ -0,0 +1,29 @@
+int printf(const char *, ...);
+void *malloc(unsigned long);
+int main() {
+   int *mem = malloc(sizeof(int) * 4000);
+
+   int cmax = 0;
+   for (int nv = 1; nv < 1000; ++nv) {
+      int n = nv, c = 0;
+      while (n != 1) {
+         if (n < nv) {
+            c += mem[n];
+            break;
+         }
+         if ((n & 1) != 0) {
+            n = (3 * n) + 1;
+         } else {
+            n /= 2;
+            //n >>= 1;
+         }
+         ++c;
+      }
+      mem[nv] = c;
+      if (c > cmax) {
+         cmax = c;
+      }
+   }
+   printf("should print 178: %d\n", cmax);
+}
+