+/**
+ * Return number of bits set in given GLuint.
+ */
+unsigned int
+_mesa_bitcount(unsigned int n)
+{
+ unsigned int bits;
+ for (bits = 0; n > 0; n = n >> 1) {
+ bits += (n & 1);
+ }
+ return bits;
+}
+
+
+/**
+ * Convert a 4-byte float to a 2-byte half float.
+ * Based on code from:
+ * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
+ */
+GLhalfARB
+_mesa_float_to_half(float val)
+{
+ const int flt = *((int *) (void *) &val);
+ const int flt_m = flt & 0x7fffff;
+ const int flt_e = (flt >> 23) & 0xff;
+ const int flt_s = (flt >> 31) & 0x1;
+ int s, e, m = 0;
+ GLhalfARB result;
+
+ /* sign bit */
+ s = flt_s;
+
+ /* handle special cases */
+ if ((flt_e == 0) && (flt_m == 0)) {
+ /* zero */
+ /* m = 0; - already set */
+ e = 0;
+ }
+ else if ((flt_e == 0) && (flt_m != 0)) {
+ /* denorm -- denorm float maps to 0 half */
+ /* m = 0; - already set */
+ e = 0;
+ }
+ else if ((flt_e == 0xff) && (flt_m == 0)) {
+ /* infinity */
+ /* m = 0; - already set */
+ e = 31;
+ }
+ else if ((flt_e == 0xff) && (flt_m != 0)) {
+ /* NaN */
+ m = 1;
+ e = 31;
+ }
+ else {
+ /* regular number */
+ const int new_exp = flt_e - 127;
+ if (new_exp < -24) {
+ /* this maps to 0 */
+ /* m = 0; - already set */
+ e = 0;
+ }
+ else if (new_exp < -14) {
+ /* this maps to a denorm */
+ unsigned int exp_val = (unsigned int) (-14 - new_exp); /* 2^-exp_val*/
+ e = 0;
+ switch (exp_val) {
+ case 0:
+ _mesa_warning(NULL,
+ "float_to_half: logical error in denorm creation!\n");
+ /* m = 0; - already set */
+ break;
+ case 1: m = 512 + (flt_m >> 14); break;
+ case 2: m = 256 + (flt_m >> 15); break;
+ case 3: m = 128 + (flt_m >> 16); break;
+ case 4: m = 64 + (flt_m >> 17); break;
+ case 5: m = 32 + (flt_m >> 18); break;
+ case 6: m = 16 + (flt_m >> 19); break;
+ case 7: m = 8 + (flt_m >> 20); break;
+ case 8: m = 4 + (flt_m >> 21); break;
+ case 9: m = 2 + (flt_m >> 22); break;
+ case 10: m = 1; break;
+ }
+ }
+ else if (new_exp > 15) {
+ /* map this value to infinity */
+ /* m = 0; - already set */
+ e = 31;
+ }
+ else {
+ /* regular */
+ e = new_exp + 15;
+ m = flt_m >> 13;
+ }
+ }
+
+ result = (s << 15) | (e << 10) | m;
+ return result;
+}
+
+
+/**
+ * Convert a 2-byte half float to a 4-byte float.
+ * Based on code from:
+ * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
+ */
+float
+_mesa_half_to_float(GLhalfARB val)
+{
+ /* XXX could also use a 64K-entry lookup table */
+ const int m = val & 0x3ff;
+ const int e = (val >> 10) & 0x1f;
+ const int s = (val >> 15) & 0x1;
+ int flt_m, flt_e, flt_s, flt;
+ float result;
+
+ /* sign bit */
+ flt_s = s;
+
+ /* handle special cases */
+ if ((e == 0) && (m == 0)) {
+ /* zero */
+ flt_m = 0;
+ flt_e = 0;
+ }
+ else if ((e == 0) && (m != 0)) {
+ /* denorm -- denorm half will fit in non-denorm single */
+ const float half_denorm = 1.0f / 16384.0f; /* 2^-14 */
+ float mantissa = ((float) (m)) / 1024.0f;
+ float sign = s ? -1.0f : 1.0f;
+ return sign * mantissa * half_denorm;
+ }
+ else if ((e == 31) && (m == 0)) {
+ /* infinity */
+ flt_e = 0xff;
+ flt_m = 0;
+ }
+ else if ((e == 31) && (m != 0)) {
+ /* NaN */
+ flt_e = 0xff;
+ flt_m = 1;
+ }
+ else {
+ /* regular */
+ flt_e = e + 112;
+ flt_m = m << 13;
+ }
+
+ flt = (flt_s << 31) | (flt_e << 23) | flt_m;
+ result = *((float *) (void *) &flt);
+ return result;
+}
+
+/*@}*/
+
+
+/**********************************************************************/
+/** \name Sort & Search */
+/*@{*/
+
+/**
+ * Wrapper for bsearch().
+ */
+void *
+_mesa_bsearch( const void *key, const void *base, size_t nmemb, size_t size,
+ int (*compar)(const void *, const void *) )
+{
+ return bsearch(key, base, nmemb, size, compar);
+}
+
+/*@}*/
+
+
+/**********************************************************************/
+/** \name Environment vars */
+/*@{*/
+
+/**
+ * Wrapper for getenv().
+ */