[llvm-commits] CVS: llvm-test/SingleSource/UnitTests/2005-05-11-Popcount-ffs-fls.c

[Duraid Madina]

Changes in directory llvm-test/SingleSource/UnitTests:

2005-05-11-Popcount-ffs-fls.c added (r1.1)
---
Log message:

add a test of the clz, popcount and ctz builtins



---
Diffs of the changes:  (+62 -0)

 2005-05-11-Popcount-ffs-fls.c |   62 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 62 insertions(+)


Index: llvm-test/SingleSource/UnitTests/2005-05-11-Popcount-ffs-fls.c
diff -c /dev/null llvm-test/SingleSource/UnitTests/2005-05-11-Popcount-ffs-fls.c:1.1
*** /dev/null	Wed May 11 02:09:05 2005
--- llvm-test/SingleSource/UnitTests/2005-05-11-Popcount-ffs-fls.c	Wed May 11 02:08:55 2005
***************
*** 0 ****
--- 1,62 ----
+ /* these first three reference functions were taken from 
+  * http://www.hackersdelight.org/HDcode/nlz.cc and
+  * http://www.hackersdelight.org/HDcode/ntz.cc
+  */
+ 
+ #define u 99
+ 
+ int nlz10b(unsigned x) {
+ 
+    static char table[64] =
+      {32,20,19, u, u,18, u, 7,  10,17, u, u,14, u, 6, u,
+        u, 9, u,16, u, u, 1,26,   u,13, u, u,24, 5, u, u,
+        u,21, u, 8,11, u,15, u,   u, u, u, 2,27, 0,25, u,
+       22, u,12, u, u, 3,28, u,  23, u, 4,29, u, u,30,31};
+ 
+    x = x | (x >> 1);    // Propagate leftmost
+    x = x | (x >> 2);    // 1-bit to the right.
+    x = x | (x >> 4);
+    x = x | (x >> 8);
+    x = x & ~(x >> 16);
+    x = (x << 9) - x;    // Multiply by 511.
+    x = (x << 11) - x;   // Multiply by 2047.
+    x = (x << 14) - x;   // Multiply by 16383.
+    return table[x >> 26];
+ }
+ 
+ int pop(unsigned x) {
+    x = x - ((x >> 1) & 0x55555555);
+    x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
+    x = (x + (x >> 4)) & 0x0F0F0F0F;
+    x = x + (x << 8);
+    x = x + (x << 16);
+    return x >> 24;
+ }
+ 
+ int ntz8(unsigned x) {
+ 
+    static char table[64] =
+      {32, 0, 1,12, 2, 6, u,13,   3, u, 7, u, u, u, u,14,
+       10, 4, u, u, 8, u, u,25,   u, u, u, u, u,21,27,15,
+       31,11, 5, u, u, u, u, u,   9, u, u,24, u, u,20,26,
+       30, u, u, u, u,23, u,19,  29, u,22,18,28,17,16, u};
+ 
+    x = (x & -x)*0x0450FBAF;
+    return table[x >> 26];
+ }
+ 
+ int i;
+ int main(void) {
+ 
+   for(i=-10; i<139045193; i*=-3) {
+     printf("LLVM: n: %d, clz(n): %d, popcount(n): %d, ctz(n): %d\n",
+ 	i, __builtin_clz(i), __builtin_popcount(i), __builtin_ctz(i));
+     printf("REF : n: %d, clz(n): %d, popcount(n): %d, ctz(n): %d\n",
+ 	i, nlz10b(i), pop(i), ntz8(i));
+     printf("  ***  \n");
+     i++;
+   }
+ 
+   return(0);
+ }
+