inital commit

1 files changed, 55 insertions, 0 deletions

diff --git a/2.8.c b/2.8.c
new file mode 100644
index 0000000..8f3ecbf
--- /dev/null
+++ b/2.8.c
@@ -0,0 +1,55 @@
+#include <stdio.h>
+
+#define INT_NBITS 32
+#define ONE 1
+
+unsigned getbits(unsigned x, int from, int to);
+void pbits(int x);
+unsigned rightrot(unsigned x, int n);
+
+int 
+main(void)
+{
+  int x = 2394234;
+
+  pbits(x);
+
+  pbits(rightrot(x, 8));
+  
+  return 0;
+}
+
+unsigned 
+getbits(unsigned x, int from, int to)
+{
+  return (x >> (from+1-to)) & ~(~(unsigned)0 << to);
+}
+
+void 
+pbits(int x)
+{
+  for (int i = INT_NBITS-1; i >= 0; i--) {
+    if (i%4 == 3)
+      printf(" ");
+
+    printf("%u", getbits(x, i, 1));
+  }
+
+  printf("\n");
+}
+
+unsigned 
+rightrot(unsigned x, int n)
+{
+  int model = (x >> n) << n;
+  for (int i = 1; i <= n; i++) {
+    int shift = n+1-i*2;
+
+    if (shift >= 0)
+      model |= ((x & (ONE << (n-i))) >> shift);
+    else
+      model |= ((x & (ONE << (n-i))) << -shift);
+  }
+
+  return model;
+}