1 files changed, 63 insertions, 0 deletions
diff --git a/libavutil/half2float.c b/libavutil/half2float.c
new file mode 100644
index 0000000000..1967126f76
--- /dev/null
+++ b/libavutil/half2float.c
@@ -0,0 +1,63 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/half2float.h"
+
+static uint32_t convertmantissa(uint32_t i)
+{
+    int32_t m = i << 13; // Zero pad mantissa bits
+    int32_t e = 0; // Zero exponent
+
+    while (!(m & 0x00800000)) { // While not normalized
+        e -= 0x00800000; // Decrement exponent (1<<23)
+        m <<= 1; // Shift mantissa
+    }
+
+    m &= ~0x00800000; // Clear leading 1 bit
+    e +=  0x38800000; // Adjust bias ((127-14)<<23)
+
+    return m | e; // Return combined number
+}
+
+void ff_init_half2float_tables(Half2FloatTables *t)
+{
+    t->mantissatable[0] = 0;
+    for (int i = 1; i < 1024; i++)
+        t->mantissatable[i] = convertmantissa(i);
+    for (int i = 1024; i < 2048; i++)
+        t->mantissatable[i] = 0x38000000UL + ((i - 1024) << 13UL);
+    for (int i = 2048; i < 3072; i++)
+        t->mantissatable[i] = t->mantissatable[i - 1024] | 0x400000UL;
+    t->mantissatable[2048] = t->mantissatable[1024];
+
+    t->exponenttable[0] = 0;
+    for (int i = 1; i < 31; i++)
+        t->exponenttable[i] = i << 23;
+    for (int i = 33; i < 63; i++)
+        t->exponenttable[i] = 0x80000000UL + ((i - 32) << 23UL);
+    t->exponenttable[31]= 0x47800000UL;
+    t->exponenttable[32]= 0x80000000UL;
+    t->exponenttable[63]= 0xC7800000UL;
+
+    t->offsettable[0] = 0;
+    for (int i = 1; i < 64; i++)
+        t->offsettable[i] = 1024;
+    t->offsettable[31] = 2048;
+    t->offsettable[32] = 0;
+    t->offsettable[63] = 2048;
+}