update

1 files changed, 119 insertions, 0 deletions

diff --git a/src/test.c b/src/test.c
new file mode 100644
index 0000000..0b0917e
--- /dev/null
+++ b/src/test.c
@@ -0,0 +1,119 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <math.h>
+
+union test {
+  double d;
+  uint64_t u;
+};
+
+int main(int argc, char** argv) {
+
+  volatile uint64_t mask;
+  volatile uint64_t min;
+  volatile uint64_t max;
+
+  volatile double d1;
+  volatile double d2;
+
+  volatile uint64_t pd1;
+  volatile uint64_t pd2;
+
+
+  // 0 .. 2^51
+
+  //       SE__________QP__
+  mask = 0b1111111111110111111111111111111111111111111111111111111111111111;
+  min  = 0b1111111111110111111111111111111111111111111111111111111111111111;
+  max  = 0b1111111111110000000000000000000000000000000000000000000000000001;
+
+  memcpy(&d1, &min, 8);
+  memcpy(&d2, &max, 8);
+
+  printf("%lf\n", d1);
+  printf("%lf\n", d2);
+
+  memcpy(&pd1, &d1, 8);
+  memcpy(&pd2, &d2, 8);
+  pd1 ^= mask;
+  pd2 ^= mask;
+
+  printf("%ld\n", pd1);
+  printf("%ld\n", pd2);
+
+  printf("\n");
+
+  // -2^51 + 1 .. -1
+
+  //       SE__________QP__
+  min  = 0b1111111111111000000000000000000000000000000000000000000000000001;
+  max  = 0b1111111111111111111111111111111111111111111111111111111111111111;
+
+  memcpy(&d1, &min, 8);
+  memcpy(&d2, &max, 8);
+
+  printf("%lf\n", d1);
+  printf("%lf\n", d2);
+
+  memcpy(&pd1, &d1, 8);
+  memcpy(&pd2, &d2, 8);
+
+  printf("%ld\n", pd1);
+  printf("%ld\n", pd2);
+
+  printf("\n");
+
+  return 0;
+
+  // -2^50 + 1 .. -1
+
+  //       SE__________QFP__
+  mask = 0b1111111111111100000000000000000000000000000000000000000000000000;
+  min  = 0b0000000000000000000000000000000000000000000000000000000000000001;
+  max  = 0b0000000000000011111111111111111111111111111111111111111111111111;
+
+  printf("%ld\n", (int64_t) (min | mask));
+  printf("%ld\n", (int64_t) (max | mask));
+
+
+  // 0 .. 2^50
+
+  //       SE__________QFP__
+  mask = 0b0000000000000011111111111111111111111111111111111111111111111111;
+  min  = 0b0000000000000100000000000000000000000000000000000000000000000000;
+  max  = 0b0000000000000111111111111111111111111111111111111111111111111111;
+
+  printf("%ld\n", (int64_t) (min & mask));
+  printf("%ld\n", (int64_t) (max & mask));
+
+
+
+
+  /* volatile union test x; */
+  /* volatile double f1; */
+  /* volatile double f2; */
+
+  /* f1 = 0.0; */
+  /* f2 = 0.0; */
+  /* x.d = f1 / f2; */
+  /* printf(" 0/0: %lx\n", x.u); */
+
+  /* f1 = -0.0; */
+  /* f2 = +0.0; */
+  /* x.d = f1 / f2; */
+  /* printf("-0/0: %lx\n", x.u); */
+
+  /* x.d = sqrt(-1); */
+  /* printf("sqrt(-1): %lx\n", x.u); */
+
+
+  /* double nan_value = fabs(sqrt(-1.0));  // Standard way to generate NaN */
+
+  /* uint64_t nan_bits; */
+  /* memcpy(&nan_bits, &nan_value, sizeof(nan_bits)); */
+
+  /* printf("NaN in hex: 0x%016lx\n", nan_bits); */
+    
+  /* return 0; */
+}