| /************************************************************************** |
| * |
| * Copyright 2009 VMware, Inc. |
| * All Rights Reserved. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the |
| * "Software"), to deal in the Software without restriction, including |
| * without limitation the rights to use, copy, modify, merge, publish, |
| * distribute, sub license, and/or sell copies of the Software, and to |
| * permit persons to whom the Software is furnished to do so, subject to |
| * the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the |
| * next paragraph) shall be included in all copies or substantial portions |
| * of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. |
| * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR |
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| * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| * |
| **************************************************************************/ |
| |
| |
| /** |
| * @file |
| * Helper functions for type conversions. |
| * |
| * We want to use the fastest type for a given computation whenever feasible. |
| * The other side of this is that we need to be able convert between several |
| * types accurately and efficiently. |
| * |
| * Conversion between types of different bit width is quite complex since a |
| * |
| * To remember there are a few invariants in type conversions: |
| * |
| * - register width must remain constant: |
| * |
| * src_type.width * src_type.length == dst_type.width * dst_type.length |
| * |
| * - total number of elements must remain constant: |
| * |
| * src_type.length * num_srcs == dst_type.length * num_dsts |
| * |
| * It is not always possible to do the conversion both accurately and |
| * efficiently, usually due to lack of adequate machine instructions. In these |
| * cases it is important not to cut shortcuts here and sacrifice accuracy, as |
| * there this functions can be used anywhere. In the future we might have a |
| * precision parameter which can gauge the accuracy vs efficiency compromise, |
| * but for now if the data conversion between two stages happens to be the |
| * bottleneck, then most likely should just avoid converting at all and run |
| * both stages with the same type. |
| * |
| * Make sure to run lp_test_conv unit test after any change to this file. |
| * |
| * @author Jose Fonseca <jfonseca@vmware.com> |
| */ |
| |
| |
| #include "util/u_debug.h" |
| #include "util/u_math.h" |
| |
| #include "lp_bld_type.h" |
| #include "lp_bld_const.h" |
| #include "lp_bld_arit.h" |
| #include "lp_bld_pack.h" |
| #include "lp_bld_conv.h" |
| |
| |
| /** |
| * Special case for converting clamped IEEE-754 floats to unsigned norms. |
| * |
| * The mathematical voodoo below may seem excessive but it is actually |
| * paramount we do it this way for several reasons. First, there is no single |
| * precision FP to unsigned integer conversion Intel SSE instruction. Second, |
| * secondly, even if there was, since the FP's mantissa takes only a fraction |
| * of register bits the typically scale and cast approach would require double |
| * precision for accurate results, and therefore half the throughput |
| * |
| * Although the result values can be scaled to an arbitrary bit width specified |
| * by dst_width, the actual result type will have the same width. |
| */ |
| LLVMValueRef |
| lp_build_clamped_float_to_unsigned_norm(LLVMBuilderRef builder, |
| struct lp_type src_type, |
| unsigned dst_width, |
| LLVMValueRef src) |
| { |
| LLVMTypeRef int_vec_type = lp_build_int_vec_type(src_type); |
| LLVMValueRef res; |
| unsigned mantissa; |
| unsigned n; |
| unsigned long long ubound; |
| unsigned long long mask; |
| double scale; |
| double bias; |
| |
| assert(src_type.floating); |
| |
| mantissa = lp_mantissa(src_type); |
| |
| /* We cannot carry more bits than the mantissa */ |
| n = MIN2(mantissa, dst_width); |
| |
| /* This magic coefficients will make the desired result to appear in the |
| * lowest significant bits of the mantissa. |
| */ |
| ubound = ((unsigned long long)1 << n); |
| mask = ubound - 1; |
| scale = (double)mask/ubound; |
| bias = (double)((unsigned long long)1 << (mantissa - n)); |
| |
| res = LLVMBuildMul(builder, src, lp_build_const_scalar(src_type, scale), ""); |
| res = LLVMBuildAdd(builder, res, lp_build_const_scalar(src_type, bias), ""); |
| res = LLVMBuildBitCast(builder, res, int_vec_type, ""); |
| |
| if(dst_width > n) { |
| int shift = dst_width - n; |
| res = LLVMBuildShl(builder, res, lp_build_int_const_scalar(src_type, shift), ""); |
| |
| /* TODO: Fill in the empty lower bits for additional precision? */ |
| /* YES: this fixes progs/trivial/tri-z-eq.c. |
| * Otherwise vertex Z=1.0 values get converted to something like |
| * 0xfffffb00 and the test for equality with 0xffffffff fails. |
| */ |
| #if 0 |
| { |
| LLVMValueRef msb; |
| msb = LLVMBuildLShr(builder, res, lp_build_int_const_scalar(src_type, dst_width - 1), ""); |
| msb = LLVMBuildShl(builder, msb, lp_build_int_const_scalar(src_type, shift), ""); |
| msb = LLVMBuildSub(builder, msb, lp_build_int_const_scalar(src_type, 1), ""); |
| res = LLVMBuildOr(builder, res, msb, ""); |
| } |
| #elif 0 |
| while(shift > 0) { |
| res = LLVMBuildOr(builder, res, LLVMBuildLShr(builder, res, lp_build_int_const_scalar(src_type, n), ""), ""); |
| shift -= n; |
| n *= 2; |
| } |
| #endif |
| } |
| else |
| res = LLVMBuildAnd(builder, res, lp_build_int_const_scalar(src_type, mask), ""); |
| |
| return res; |
| } |
| |
| |
| /** |
| * Inverse of lp_build_clamped_float_to_unsigned_norm above. |
| */ |
| LLVMValueRef |
| lp_build_unsigned_norm_to_float(LLVMBuilderRef builder, |
| unsigned src_width, |
| struct lp_type dst_type, |
| LLVMValueRef src) |
| { |
| LLVMTypeRef vec_type = lp_build_vec_type(dst_type); |
| LLVMTypeRef int_vec_type = lp_build_int_vec_type(dst_type); |
| LLVMValueRef bias_; |
| LLVMValueRef res; |
| unsigned mantissa; |
| unsigned n; |
| unsigned long long ubound; |
| unsigned long long mask; |
| double scale; |
| double bias; |
| |
| mantissa = lp_mantissa(dst_type); |
| |
| n = MIN2(mantissa, src_width); |
| |
| ubound = ((unsigned long long)1 << n); |
| mask = ubound - 1; |
| scale = (double)ubound/mask; |
| bias = (double)((unsigned long long)1 << (mantissa - n)); |
| |
| res = src; |
| |
| if(src_width > mantissa) { |
| int shift = src_width - mantissa; |
| res = LLVMBuildLShr(builder, res, lp_build_int_const_scalar(dst_type, shift), ""); |
| } |
| |
| bias_ = lp_build_const_scalar(dst_type, bias); |
| |
| res = LLVMBuildOr(builder, |
| res, |
| LLVMBuildBitCast(builder, bias_, int_vec_type, ""), ""); |
| |
| res = LLVMBuildBitCast(builder, res, vec_type, ""); |
| |
| res = LLVMBuildSub(builder, res, bias_, ""); |
| res = LLVMBuildMul(builder, res, lp_build_const_scalar(dst_type, scale), ""); |
| |
| return res; |
| } |
| |
| |
| /** |
| * Generic type conversion. |
| * |
| * TODO: Take a precision argument, or even better, add a new precision member |
| * to the lp_type union. |
| */ |
| void |
| lp_build_conv(LLVMBuilderRef builder, |
| struct lp_type src_type, |
| struct lp_type dst_type, |
| const LLVMValueRef *src, unsigned num_srcs, |
| LLVMValueRef *dst, unsigned num_dsts) |
| { |
| struct lp_type tmp_type; |
| LLVMValueRef tmp[LP_MAX_VECTOR_LENGTH]; |
| unsigned num_tmps; |
| unsigned i; |
| |
| /* Register width must remain constant */ |
| assert(src_type.width * src_type.length == dst_type.width * dst_type.length); |
| |
| /* We must not loose or gain channels. Only precision */ |
| assert(src_type.length * num_srcs == dst_type.length * num_dsts); |
| |
| assert(src_type.length <= LP_MAX_VECTOR_LENGTH); |
| assert(dst_type.length <= LP_MAX_VECTOR_LENGTH); |
| |
| tmp_type = src_type; |
| for(i = 0; i < num_srcs; ++i) |
| tmp[i] = src[i]; |
| num_tmps = num_srcs; |
| |
| /* |
| * Clamp if necessary |
| */ |
| |
| if(memcmp(&src_type, &dst_type, sizeof src_type) != 0) { |
| struct lp_build_context bld; |
| double src_min = lp_const_min(src_type); |
| double dst_min = lp_const_min(dst_type); |
| double src_max = lp_const_max(src_type); |
| double dst_max = lp_const_max(dst_type); |
| LLVMValueRef thres; |
| |
| lp_build_context_init(&bld, builder, tmp_type); |
| |
| if(src_min < dst_min) { |
| if(dst_min == 0.0) |
| thres = bld.zero; |
| else |
| thres = lp_build_const_scalar(src_type, dst_min); |
| for(i = 0; i < num_tmps; ++i) |
| tmp[i] = lp_build_max(&bld, tmp[i], thres); |
| } |
| |
| if(src_max > dst_max) { |
| if(dst_max == 1.0) |
| thres = bld.one; |
| else |
| thres = lp_build_const_scalar(src_type, dst_max); |
| for(i = 0; i < num_tmps; ++i) |
| tmp[i] = lp_build_min(&bld, tmp[i], thres); |
| } |
| } |
| |
| /* |
| * Scale to the narrowest range |
| */ |
| |
| if(dst_type.floating) { |
| /* Nothing to do */ |
| } |
| else if(tmp_type.floating) { |
| if(!dst_type.fixed && !dst_type.sign && dst_type.norm) { |
| for(i = 0; i < num_tmps; ++i) { |
| tmp[i] = lp_build_clamped_float_to_unsigned_norm(builder, |
| tmp_type, |
| dst_type.width, |
| tmp[i]); |
| } |
| tmp_type.floating = FALSE; |
| } |
| else { |
| double dst_scale = lp_const_scale(dst_type); |
| LLVMTypeRef tmp_vec_type; |
| |
| if (dst_scale != 1.0) { |
| LLVMValueRef scale = lp_build_const_scalar(tmp_type, dst_scale); |
| for(i = 0; i < num_tmps; ++i) |
| tmp[i] = LLVMBuildMul(builder, tmp[i], scale, ""); |
| } |
| |
| /* Use an equally sized integer for intermediate computations */ |
| tmp_type.floating = FALSE; |
| tmp_vec_type = lp_build_vec_type(tmp_type); |
| for(i = 0; i < num_tmps; ++i) { |
| #if 0 |
| if(dst_type.sign) |
| tmp[i] = LLVMBuildFPToSI(builder, tmp[i], tmp_vec_type, ""); |
| else |
| tmp[i] = LLVMBuildFPToUI(builder, tmp[i], tmp_vec_type, ""); |
| #else |
| /* FIXME: there is no SSE counterpart for LLVMBuildFPToUI */ |
| tmp[i] = LLVMBuildFPToSI(builder, tmp[i], tmp_vec_type, ""); |
| #endif |
| } |
| } |
| } |
| else { |
| unsigned src_shift = lp_const_shift(src_type); |
| unsigned dst_shift = lp_const_shift(dst_type); |
| |
| /* FIXME: compensate different offsets too */ |
| if(src_shift > dst_shift) { |
| LLVMValueRef shift = lp_build_int_const_scalar(tmp_type, src_shift - dst_shift); |
| for(i = 0; i < num_tmps; ++i) |
| if(src_type.sign) |
| tmp[i] = LLVMBuildAShr(builder, tmp[i], shift, ""); |
| else |
| tmp[i] = LLVMBuildLShr(builder, tmp[i], shift, ""); |
| } |
| } |
| |
| /* |
| * Truncate or expand bit width |
| */ |
| |
| assert(!tmp_type.floating || tmp_type.width == dst_type.width); |
| |
| if(tmp_type.width > dst_type.width) { |
| assert(num_dsts == 1); |
| tmp[0] = lp_build_pack(builder, tmp_type, dst_type, TRUE, tmp, num_tmps); |
| tmp_type.width = dst_type.width; |
| tmp_type.length = dst_type.length; |
| num_tmps = 1; |
| } |
| |
| if(tmp_type.width < dst_type.width) { |
| assert(num_tmps == 1); |
| lp_build_unpack(builder, tmp_type, dst_type, tmp[0], tmp, num_dsts); |
| tmp_type.width = dst_type.width; |
| tmp_type.length = dst_type.length; |
| num_tmps = num_dsts; |
| } |
| |
| assert(tmp_type.width == dst_type.width); |
| assert(tmp_type.length == dst_type.length); |
| assert(num_tmps == num_dsts); |
| |
| /* |
| * Scale to the widest range |
| */ |
| |
| if(src_type.floating) { |
| /* Nothing to do */ |
| } |
| else if(!src_type.floating && dst_type.floating) { |
| if(!src_type.fixed && !src_type.sign && src_type.norm) { |
| for(i = 0; i < num_tmps; ++i) { |
| tmp[i] = lp_build_unsigned_norm_to_float(builder, |
| src_type.width, |
| dst_type, |
| tmp[i]); |
| } |
| tmp_type.floating = TRUE; |
| } |
| else { |
| double src_scale = lp_const_scale(src_type); |
| LLVMTypeRef tmp_vec_type; |
| |
| /* Use an equally sized integer for intermediate computations */ |
| tmp_type.floating = TRUE; |
| tmp_type.sign = TRUE; |
| tmp_vec_type = lp_build_vec_type(tmp_type); |
| for(i = 0; i < num_tmps; ++i) { |
| #if 0 |
| if(dst_type.sign) |
| tmp[i] = LLVMBuildSIToFP(builder, tmp[i], tmp_vec_type, ""); |
| else |
| tmp[i] = LLVMBuildUIToFP(builder, tmp[i], tmp_vec_type, ""); |
| #else |
| /* FIXME: there is no SSE counterpart for LLVMBuildUIToFP */ |
| tmp[i] = LLVMBuildSIToFP(builder, tmp[i], tmp_vec_type, ""); |
| #endif |
| } |
| |
| if (src_scale != 1.0) { |
| LLVMValueRef scale = lp_build_const_scalar(tmp_type, 1.0/src_scale); |
| for(i = 0; i < num_tmps; ++i) |
| tmp[i] = LLVMBuildMul(builder, tmp[i], scale, ""); |
| } |
| } |
| } |
| else { |
| unsigned src_shift = lp_const_shift(src_type); |
| unsigned dst_shift = lp_const_shift(dst_type); |
| |
| /* FIXME: compensate different offsets too */ |
| if(src_shift < dst_shift) { |
| LLVMValueRef shift = lp_build_int_const_scalar(tmp_type, dst_shift - src_shift); |
| for(i = 0; i < num_tmps; ++i) |
| tmp[i] = LLVMBuildShl(builder, tmp[i], shift, ""); |
| } |
| } |
| |
| for(i = 0; i < num_dsts; ++i) |
| dst[i] = tmp[i]; |
| } |
| |
| |
| /** |
| * Bit mask conversion. |
| * |
| * This will convert the integer masks that match the given types. |
| * |
| * The mask values should 0 or -1, i.e., all bits either set to zero or one. |
| * Any other value will likely cause in unpredictable results. |
| * |
| * This is basically a very trimmed down version of lp_build_conv. |
| */ |
| void |
| lp_build_conv_mask(LLVMBuilderRef builder, |
| struct lp_type src_type, |
| struct lp_type dst_type, |
| const LLVMValueRef *src, unsigned num_srcs, |
| LLVMValueRef *dst, unsigned num_dsts) |
| { |
| /* Register width must remain constant */ |
| assert(src_type.width * src_type.length == dst_type.width * dst_type.length); |
| |
| /* We must not loose or gain channels. Only precision */ |
| assert(src_type.length * num_srcs == dst_type.length * num_dsts); |
| |
| /* |
| * Drop |
| * |
| * We assume all values are 0 or -1 |
| */ |
| |
| src_type.floating = FALSE; |
| src_type.fixed = FALSE; |
| src_type.sign = TRUE; |
| src_type.norm = FALSE; |
| |
| dst_type.floating = FALSE; |
| dst_type.fixed = FALSE; |
| dst_type.sign = TRUE; |
| dst_type.norm = FALSE; |
| |
| /* |
| * Truncate or expand bit width |
| */ |
| |
| if(src_type.width > dst_type.width) { |
| assert(num_dsts == 1); |
| dst[0] = lp_build_pack(builder, src_type, dst_type, TRUE, src, num_srcs); |
| } |
| else if(src_type.width < dst_type.width) { |
| assert(num_srcs == 1); |
| lp_build_unpack(builder, src_type, dst_type, src[0], dst, num_dsts); |
| } |
| else { |
| assert(num_srcs == num_dsts); |
| memcpy(dst, src, num_dsts * sizeof *dst); |
| } |
| } |