-
-/**
- * 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 fi_type fi = {val};
- const int flt_m = fi.i & 0x7fffff;
- const int flt_e = (fi.i >> 23) & 0xff;
- const int flt_s = (fi.i >> 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;
- fi_type fi;
- 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;
- }
-
- fi.i = (flt_s << 31) | (flt_e << 23) | flt_m;
- result = fi.f;
- 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 *) )
-{
-#if defined(_WIN32_WCE)
- void *mid;
- int cmp;
- while (nmemb) {
- nmemb >>= 1;
- mid = (char *)base + nmemb * size;
- cmp = (*compar)(key, mid);
- if (cmp == 0)
- return mid;
- if (cmp > 0) {
- base = (char *)mid + size;
- --nmemb;
- }
- }
- return NULL;
-#else
- return bsearch(key, base, nmemb, size, compar);
-#endif
-}
-
-/*@}*/
-
-
-/**********************************************************************/
-/** \name Environment vars */
-/*@{*/
-
-/**
- * Wrapper for getenv().
- */
-char *
-_mesa_getenv( const char *var )
-{
-#if defined(_XBOX) || defined(_WIN32_WCE)
- return NULL;
-#else
- return getenv(var);
-#endif
-}
-
-/*@}*/
-
-
-/**********************************************************************/
-/** \name String */
-/*@{*/
-
-/**
- * Implemented using malloc() and strcpy.
- * Note that NULL is handled accordingly.
- */
-char *
-_mesa_strdup( const char *s )
-{
- if (s) {
- size_t l = strlen(s);
- char *s2 = malloc(l + 1);
- if (s2)
- strcpy(s2, s);
- return s2;
- }
- else {
- return NULL;
- }
-}
-
-/** Wrapper around strtof() */
-float
-_mesa_strtof( const char *s, char **end )
-{
-#if defined(_GNU_SOURCE) && !defined(__CYGWIN__) && !defined(__FreeBSD__) && \
- !defined(ANDROID) && !defined(__HAIKU__) && !defined(__UCLIBC__)
- static locale_t loc = NULL;
- if (!loc) {
- loc = newlocale(LC_CTYPE_MASK, "C", NULL);
- }
- return strtof_l(s, end, loc);
-#elif defined(_ISOC99_SOURCE) || (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE >= 600)
- return strtof(s, end);
-#else
- return (float)strtod(s, end);
-#endif
-}
-
-/** Compute simple checksum/hash for a string */
-unsigned int
-_mesa_str_checksum(const char *str)
-{
- /* This could probably be much better */
- unsigned int sum, i;
- const char *c;
- sum = i = 1;
- for (c = str; *c; c++, i++)
- sum += *c * (i % 100);
- return sum + i;
-}
-
-