diff options
| author | Zack Rusin <[email protected]> | 2013-07-18 02:38:54 -0400 |
|---|---|---|
| committer | Zack Rusin <[email protected]> | 2013-07-19 16:29:17 -0400 |
| commit | 7b672c1503abffcc83a30a9731419539f52ac73f (patch) | |
| tree | f91b624cecf8c178e9b6e286b27097200348b0fd | |
| parent | ab47bbecd64d05d4fe03bed28291387dd08f5b84 (diff) | |
gallivm: fix edge cases in exp2
exp(0) has to be exactly 1, exp(-inf) has to be 0, exp(inf) has
to be inf and exp(nan) has to be nan, this fixes all of those
cases.
Signed-off-by: Zack Rusin <[email protected]>
Reviewed-by: Jose Fonseca <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>
| -rw-r--r-- | src/gallium/auxiliary/gallivm/lp_bld_arit.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c index d2d91f50da9..34e3ed94542 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c @@ -3141,7 +3141,7 @@ lp_build_polynomial(struct lp_build_context *bld, */ const double lp_build_exp2_polynomial[] = { #if EXP_POLY_DEGREE == 5 - 0.999999925063526176901, + 1.000000000000000000000, /*XXX: was 0.999999925063526176901, recompute others */ 0.693153073200168932794, 0.240153617044375388211, 0.0558263180532956664775, @@ -3196,8 +3196,12 @@ lp_build_exp2_approx(struct lp_build_context *bld, assert(type.floating && type.width == 32); - x = lp_build_min(bld, x, lp_build_const_vec(bld->gallivm, type, 129.0)); - x = lp_build_max(bld, x, lp_build_const_vec(bld->gallivm, type, -126.99999)); + /* We want to preserve NaN and make sure than for exp2 if x > 128, + * the result is INF and if it's smaller than -126.9 the result is 0 */ + x = lp_build_min_ext(bld, lp_build_const_vec(bld->gallivm, type, 128.0), x, + GALLIVM_NAN_RETURN_SECOND); + x = lp_build_max_ext(bld, lp_build_const_vec(bld->gallivm, type, -126.99999), x, + GALLIVM_NAN_RETURN_SECOND); /* ipart = floor(x) */ /* fpart = x - ipart */ |