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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   */
42  LLVMValueRef
lp_build_gather_elem_ptr(struct gallivm_state * gallivm,unsigned length,LLVMValueRef base_ptr,LLVMValueRef offsets,unsigned i)43  lp_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   */
73  LLVMValueRef
lp_build_gather_elem(struct gallivm_state * gallivm,unsigned length,unsigned src_width,unsigned dst_width,LLVMValueRef base_ptr,LLVMValueRef offsets,unsigned i)74  lp_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   */
115  LLVMValueRef
lp_build_gather(struct gallivm_state * gallivm,unsigned length,unsigned src_width,unsigned dst_width,LLVMValueRef base_ptr,LLVMValueRef offsets)116  lp_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  
151  LLVMValueRef
lp_build_gather_values(struct gallivm_state * gallivm,LLVMValueRef * values,unsigned value_count)152  lp_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