1/**************************************************************************
2 *
3 * Copyright 2010 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
18 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
19 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
20 * USE OR OTHER DEALINGS IN THE SOFTWARE.
21 *
22 * The above copyright notice and this permission notice (including the
23 * next paragraph) shall be included in all copies or substantial portions
24 * of the Software.
25 *
26 **************************************************************************/
27
28
29#include "util/u_debug.h"
30#include "lp_bld_debug.h"
31#include "lp_bld_const.h"
32#include "lp_bld_format.h"
33#include "lp_bld_gather.h"
34#include "lp_bld_init.h"
35
36
37/**
38 * Get the pointer to one element from scatter positions in memory.
39 *
40 * @sa lp_build_gather()
41 */
42LLVMValueRef
43lp_build_gather_elem_ptr(struct gallivm_state *gallivm,
44                         unsigned length,
45                         LLVMValueRef base_ptr,
46                         LLVMValueRef offsets,
47                         unsigned i)
48{
49   LLVMValueRef offset;
50   LLVMValueRef ptr;
51
52   assert(LLVMTypeOf(base_ptr) == LLVMPointerType(LLVMInt8TypeInContext(gallivm->context), 0));
53
54   if (length == 1) {
55      assert(i == 0);
56      offset = offsets;
57   } else {
58      LLVMValueRef index = lp_build_const_int32(gallivm, i);
59      offset = LLVMBuildExtractElement(gallivm->builder, offsets, index, "");
60   }
61
62   ptr = LLVMBuildGEP(gallivm->builder, base_ptr, &offset, 1, "");
63
64   return ptr;
65}
66
67
68/**
69 * Gather one element from scatter positions in memory.
70 *
71 * @sa lp_build_gather()
72 */
73LLVMValueRef
74lp_build_gather_elem(struct gallivm_state *gallivm,
75                     unsigned length,
76                     unsigned src_width,
77                     unsigned dst_width,
78                     LLVMValueRef base_ptr,
79                     LLVMValueRef offsets,
80                     unsigned i)
81{
82   LLVMTypeRef src_type = LLVMIntTypeInContext(gallivm->context, src_width);
83   LLVMTypeRef src_ptr_type = LLVMPointerType(src_type, 0);
84   LLVMTypeRef dst_elem_type = LLVMIntTypeInContext(gallivm->context, dst_width);
85   LLVMValueRef ptr;
86   LLVMValueRef res;
87
88   assert(LLVMTypeOf(base_ptr) == LLVMPointerType(LLVMInt8TypeInContext(gallivm->context), 0));
89
90   ptr = lp_build_gather_elem_ptr(gallivm, length, base_ptr, offsets, i);
91   ptr = LLVMBuildBitCast(gallivm->builder, ptr, src_ptr_type, "");
92   res = LLVMBuildLoad(gallivm->builder, ptr, "");
93
94   assert(src_width <= dst_width);
95   if (src_width > dst_width)
96      res = LLVMBuildTrunc(gallivm->builder, res, dst_elem_type, "");
97   if (src_width < dst_width)
98      res = LLVMBuildZExt(gallivm->builder, res, dst_elem_type, "");
99
100   return res;
101}
102
103
104/**
105 * Gather elements from scatter positions in memory into a single vector.
106 * Use for fetching texels from a texture.
107 * For SSE, typical values are length=4, src_width=32, dst_width=32.
108 *
109 * @param length length of the offsets
110 * @param src_width src element width in bits
111 * @param dst_width result element width in bits (src will be expanded to fit)
112 * @param base_ptr base pointer, should be a i8 pointer type.
113 * @param offsets vector with offsets
114 */
115LLVMValueRef
116lp_build_gather(struct gallivm_state *gallivm,
117                unsigned length,
118                unsigned src_width,
119                unsigned dst_width,
120                LLVMValueRef base_ptr,
121                LLVMValueRef offsets)
122{
123   LLVMValueRef res;
124
125   if (length == 1) {
126      /* Scalar */
127      return lp_build_gather_elem(gallivm, length,
128                                  src_width, dst_width,
129                                  base_ptr, offsets, 0);
130   } else {
131      /* Vector */
132
133      LLVMTypeRef dst_elem_type = LLVMIntTypeInContext(gallivm->context, dst_width);
134      LLVMTypeRef dst_vec_type = LLVMVectorType(dst_elem_type, length);
135      unsigned i;
136
137      res = LLVMGetUndef(dst_vec_type);
138      for (i = 0; i < length; ++i) {
139         LLVMValueRef index = lp_build_const_int32(gallivm, i);
140         LLVMValueRef elem;
141         elem = lp_build_gather_elem(gallivm, length,
142                                     src_width, dst_width,
143                                     base_ptr, offsets, i);
144         res = LLVMBuildInsertElement(gallivm->builder, res, elem, index, "");
145      }
146   }
147
148   return res;
149}
150
151LLVMValueRef
152lp_build_gather_values(struct gallivm_state * gallivm,
153                       LLVMValueRef * values,
154                       unsigned value_count)
155{
156   LLVMTypeRef vec_type = LLVMVectorType(LLVMTypeOf(values[0]), value_count);
157   LLVMBuilderRef builder = gallivm->builder;
158   LLVMValueRef vec = LLVMGetUndef(vec_type);
159   unsigned i;
160
161   for (i = 0; i < value_count; i++) {
162      LLVMValueRef index = lp_build_const_int32(gallivm, i);
163      vec = LLVMBuildInsertElement(builder, vec, values[i], index, "");
164   }
165   return vec;
166}
167