From: Marek Olšák <marek.ol...@amd.com> This fixes the build if __builtin_clz is unsupported. --- src/util/half_float.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/src/util/half_float.c b/src/util/half_float.c index 588f050d924..2eff2c84f51 100644 --- a/src/util/half_float.c +++ b/src/util/half_float.c @@ -208,21 +208,31 @@ uint8_t _mesa_half_to_unorm8(uint16_t val) * Takes a uint16_t, divides by 65536, converts the infinite-precision * result to fp16 with round-to-zero. Used by the ASTC decoder. */ uint16_t _mesa_uint16_div_64k_to_half(uint16_t v) { /* Zero or subnormal. Set the mantissa to (v << 8) and return. */ if (v < 4) return v << 8; /* Count the leading 0s in the uint16_t */ - int n = __builtin_clz(v) - (sizeof(unsigned int) - sizeof(uint16_t)) * 8; +#ifdef HAVE___BUILTIN_CLZ + int n = __builtin_clz(v) - 16; +#else + int n = 16; + for (int i = 15; i >= 0; i--) { + if (v & (1 << i)) { + n = 15 - i; + break; + } + } +#endif /* Shift the mantissa up so bit 16 is the hidden 1 bit, * mask it off, then shift back down to 10 bits */ int m = ( ((uint32_t)v << (n + 1)) & 0xffff ) >> 6; /* (0{n} 1 X{15-n}) * 2^-16 * = 1.X * 2^(15-n-16) * = 1.X * 2^(14-n - 15) * which is the FP16 form with e = 14 - n -- 2.17.1 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev