diff options
| -rw-r--r-- | src/gallium/auxiliary/gallivm/lp_bld_conv.c | 96 | ||||
| -rw-r--r-- | src/gallium/auxiliary/gallivm/lp_bld_conv.h | 5 |
2 files changed, 94 insertions, 7 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_conv.c b/src/gallium/auxiliary/gallivm/lp_bld_conv.c index 0399709faad..af942ada2c2 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_conv.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_conv.c @@ -78,18 +78,19 @@ * Note this can be performed in 1 instruction if vcvtph2ps exists (sse5 i think?) * [llvm.x86.vcvtph2ps / _mm_cvtph_ps] * - * @param src_type <vector> type of int16 * @param src value to convert * * ref http://fgiesen.wordpress.com/2012/03/28/half-to-float-done-quic/ + * ref https://gist.github.com/2144712 */ LLVMValueRef lp_build_half_to_float(struct gallivm_state *gallivm, - struct lp_type src_type, - LLVMValueRef src) + LLVMValueRef src) { - struct lp_type f32_type = lp_type_float_vec(32, 32 * src_type.length); - struct lp_type i32_type = lp_type_int_vec(32, 32 * src_type.length); + int src_length = LLVMGetVectorSize(LLVMTypeOf(src)); + + struct lp_type f32_type = lp_type_float_vec(32, 32 * src_length); + struct lp_type i32_type = lp_type_int_vec(32, 32 * src_length); LLVMBuilderRef builder = gallivm->builder; LLVMTypeRef int_vec_type = lp_build_vec_type(gallivm, i32_type); @@ -133,6 +134,76 @@ lp_build_half_to_float(struct gallivm_state *gallivm, /** + * Converts float32 to int16 half-float + * Note this can be performed in 1 instruction if vcvtps2ph exists (sse5 i think?) + * [llvm.x86.vcvtps2ph / _mm_cvtps_ph] + * + * @param src value to convert + * + * ref http://fgiesen.wordpress.com/2012/03/28/half-to-float-done-quic/ + * ref https://gist.github.com/2156668 + */ +LLVMValueRef +lp_build_float_to_half(struct gallivm_state *gallivm, + LLVMValueRef src) +{ + struct lp_type i32_type = lp_type_int_vec(32, 32 * LLVMGetVectorSize(LLVMTypeOf(src))); + + LLVMBuilderRef builder = gallivm->builder; + LLVMTypeRef int_vec_type = lp_build_vec_type(gallivm, i32_type); + + struct lp_build_context bld; + + LLVMValueRef result; + + lp_build_context_init(&bld, gallivm, i32_type); + + /* Extra scope because lp_build_min needs a build context, le sigh */ + { + /* Constants */ + LLVMValueRef i32_13 = lp_build_const_int_vec(gallivm, i32_type, 13); + LLVMValueRef i32_16 = lp_build_const_int_vec(gallivm, i32_type, 16); + LLVMValueRef i32_mask_fabs = lp_build_const_int_vec(gallivm, i32_type, 0x7fffffff); + LLVMValueRef i32_f32infty = lp_build_const_int_vec(gallivm, i32_type, 0xff << 23); + LLVMValueRef i32_expinf = lp_build_const_int_vec(gallivm, i32_type, 0xe0 << 23); + LLVMValueRef i32_f16max = lp_build_const_int_vec(gallivm, i32_type, 0x8f << 23); + LLVMValueRef i32_magic = lp_build_const_int_vec(gallivm, i32_type, 0x0f << 23); + + /* Cast from float32 to int32 */ + LLVMValueRef f = LLVMBuildBitCast(builder, src, int_vec_type, ""); + + /* Remove sign */ + LLVMValueRef fabs = LLVMBuildAnd(builder, i32_mask_fabs, f, ""); + + /* Magic conversion */ + LLVMValueRef clamped = lp_build_min(&bld, i32_f16max, fabs); + LLVMValueRef scaled = LLVMBuildMul(builder, clamped, i32_magic, ""); + + /* Make sure Inf/NaN and unormalised survive */ + LLVMValueRef infnancase = LLVMBuildXor(builder, i32_expinf, fabs, ""); + LLVMValueRef b_notnormal = lp_build_compare(gallivm, i32_type, PIPE_FUNC_GREATER, fabs, i32_f32infty); + + /* Merge normal / unnormal case */ + LLVMValueRef merge1 = LLVMBuildAnd(builder, infnancase, b_notnormal, ""); + LLVMValueRef merge2 = LLVMBuildNot(builder, LLVMBuildAnd(builder, b_notnormal, scaled, ""), ""); + LLVMValueRef merged = LLVMBuildOr(builder, merge1, merge2, ""); + LLVMValueRef shifted = LLVMBuildLShr(builder, merged, i32_13, ""); + + /* Sign bit */ + LLVMValueRef justsign = LLVMBuildXor(builder, f, fabs, ""); + LLVMValueRef signshifted = LLVMBuildLShr(builder, justsign, i32_16, ""); + + /* Combine result */ + result = LLVMBuildOr(builder, shifted, signshifted, ""); + } + + /* Truncate from 32 bit to 16 bit */ + i32_type.width = 16; + return LLVMBuildTrunc(builder, result, lp_build_vec_type(gallivm, i32_type), ""); +} + + +/** * Special case for converting clamped IEEE-754 floats to unsigned norms. * * The mathematical voodoo below may seem excessive but it is actually @@ -493,12 +564,25 @@ lp_build_conv(struct gallivm_state *gallivm, return; } + /* Special case -> 16bit half-float + */ + else if (dst_type.floating && dst_type.width == 16) + { + /* Only support src as 32bit float currently */ + assert(src_type.floating && src_type.width == 32); + + for(i = 0; i < num_tmps; ++i) + dst[i] = lp_build_float_to_half(gallivm, tmp[i]); + + return; + } + /* Pre convert half-floats to floats */ else if (src_type.floating && src_type.width == 16) { for(i = 0; i < num_tmps; ++i) - tmp[i] = lp_build_half_to_float(gallivm, src_type, tmp[i]); + tmp[i] = lp_build_half_to_float(gallivm, tmp[i]); tmp_type.width = 32; } diff --git a/src/gallium/auxiliary/gallivm/lp_bld_conv.h b/src/gallium/auxiliary/gallivm/lp_bld_conv.h index c830fbef5f2..ef221051bcd 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_conv.h +++ b/src/gallium/auxiliary/gallivm/lp_bld_conv.h @@ -44,7 +44,10 @@ struct lp_type; LLVMValueRef lp_build_half_to_float(struct gallivm_state *gallivm, - struct lp_type src_type, + LLVMValueRef src); + +LLVMValueRef +lp_build_float_to_half(struct gallivm_state *gallivm, LLVMValueRef src); LLVMValueRef |