diff options
| author | Marek Olšák <[email protected]> | 2018-07-31 22:50:44 -0400 |
|---|---|---|
| committer | Marek Olšák <[email protected]> | 2018-07-31 23:28:01 -0400 |
| commit | 157c6e81958d3b2223adf5567722b0502ada78ec (patch) | |
| tree | 6e90b4dcd64cb6f70ed60308b542718bbaa77caa | |
| parent | c5c6e0187fd5d535c304ca3fd62de0f5e636c0c2 (diff) | |
util: don't use __builtin_clz unconditionally
This fixes the build if __builtin_clz is unsupported.
Reviewed-by: Roland Scheidegger <[email protected]>
| -rw-r--r-- | src/util/half_float.c | 12 |
1 files changed, 11 insertions, 1 deletions
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 @@ -215,7 +215,17 @@ uint16_t _mesa_uint16_div_64k_to_half(uint16_t v) 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 |