/*
* Mesa 3-D graphics library
- * Version: 7.1
*
* Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
- * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
*/
#ifdef _WIN32
#define vsnprintf _vsnprintf
-#elif defined(__IBMC__) || defined(__IBMCPP__) || ( defined(__VMS) && __CRTL_VER < 70312000 )
+#elif defined(__IBMC__) || defined(__IBMCPP__)
extern int vsnprintf(char *str, size_t count, const char *fmt, va_list arg);
-#ifdef __VMS
-#include "vsnprintf.c"
-#endif
#endif
/**********************************************************************/
ASSERT( alignment > 0 );
- ptr = malloc(bytes + alignment + sizeof(void *));
+ ptr = (uintptr_t)malloc(bytes + alignment + sizeof(void *));
if (!ptr)
return NULL;
ASSERT( alignment > 0 );
- ptr = calloc(1, bytes + alignment + sizeof(void *));
+ ptr = (uintptr_t)calloc(1, bytes + alignment + sizeof(void *));
if (!ptr)
return NULL;
* \param ptr pointer to the memory to be freed.
* The actual address to free is stored in the word immediately before the
* address the client sees.
+ * Note that it is legal to pass NULL pointer to this function and will be
+ * handled accordingly.
*/
void
_mesa_align_free(void *ptr)
#elif defined(_WIN32) && defined(_MSC_VER)
_aligned_free(ptr);
#else
- void **cubbyHole = (void **) ((char *) ptr - sizeof(void *));
- void *realAddr = *cubbyHole;
- free(realAddr);
+ if (ptr) {
+ void **cubbyHole = (void **) ((char *) ptr - sizeof(void *));
+ void *realAddr = *cubbyHole;
+ free(realAddr);
+ }
#endif /* defined(HAVE_POSIX_MEMALIGN) */
}
if (newBuf && oldBuffer && copySize > 0) {
memcpy(newBuf, oldBuffer, copySize);
}
- if (oldBuffer)
- _mesa_align_free(oldBuffer);
+
+ _mesa_align_free(oldBuffer);
return newBuf;
#endif
}
#endif
+/* Using C99 rounding functions for roundToEven() implementation is
+ * difficult, because round(), rint, and nearbyint() are affected by
+ * fesetenv(), which the application may have done for its own
+ * purposes. Mesa's IROUND macro is close to what we want, but it
+ * rounds away from 0 on n + 0.5.
+ */
+int
+_mesa_round_to_even(float val)
+{
+ int rounded = IROUND(val);
+
+ if (val - floor(val) == 0.5) {
+ if (rounded % 2 != 0)
+ rounded += val > 0 ? -1 : 1;
+ }
+
+ return rounded;
+}
+
+
/**
* 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
+ *
+ * Not all float32 values can be represented exactly as a float16 value. We
+ * round such intermediate float32 values to the nearest float16. When the
+ * float32 lies exactly between to float16 values, we round to the one with
+ * an even mantissa.
+ *
+ * This rounding behavior has several benefits:
+ * - It has no sign bias.
+ *
+ * - It reproduces the behavior of real hardware: opcode F32TO16 in Intel's
+ * GPU ISA.
+ *
+ * - By reproducing the behavior of the GPU (at least on Intel hardware),
+ * compile-time evaluation of constant packHalf2x16 GLSL expressions will
+ * result in the same value as if the expression were executed on the GPU.
*/
GLhalfARB
_mesa_float_to_half(float val)
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*/
+ if (new_exp < -14) {
+ /* The float32 lies in the range (0.0, min_normal16) and is rounded
+ * to a nearby float16 value. The result will be either zero, subnormal,
+ * or normal.
+ */
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;
- }
+ m = _mesa_round_to_even((1 << 24) * fabsf(fi.f));
}
else if (new_exp > 15) {
/* map this value to infinity */
e = 31;
}
else {
- /* regular */
+ /* The float32 lies in the range
+ * [min_normal16, max_normal16 + max_step16)
+ * and is rounded to a nearby float16 value. The result will be
+ * either normal or infinite.
+ */
e = new_exp + 15;
- m = flt_m >> 13;
+ m = _mesa_round_to_even(flt_m / (float) (1 << 13));
}
}
+ assert(0 <= m && m <= 1024);
+ if (m == 1024) {
+ /* The float32 was rounded upwards into the range of the next exponent,
+ * so bump the exponent. This correctly handles the case where f32
+ * should be rounded up to float16 infinity.
+ */
+ ++e;
+ m = 0;
+ }
+
result = (s << 15) | (e << 10) | m;
return result;
}
_mesa_strtof( const char *s, char **end )
{
#if defined(_GNU_SOURCE) && !defined(__CYGWIN__) && !defined(__FreeBSD__) && \
- !defined(ANDROID) && !defined(__HAIKU__) && !defined(__UCLIBC__)
+ !defined(ANDROID) && !defined(__HAIKU__) && !defined(__UCLIBC__) && \
+ !defined(__NetBSD__)
static locale_t loc = NULL;
if (!loc) {
loc = newlocale(LC_CTYPE_MASK, "C", NULL);
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