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authorMichal Krol <michal@tungstengraphics.com>2008-11-12 23:23:49 +0100
committerMichal Krol <michal@tungstengraphics.com>2008-11-12 23:25:43 +0100
commit26c8593093bd9e42d06a54ed8cfdedce2fb44332 (patch)
tree5fd039fc040c33fd974db1196e4e7e39dbc8631e
parent44257a8e752a5f10aed7e5797b23cdb42120703c (diff)
tgsi: More comments on source register indirect and 2D indexing.
-rw-r--r--src/gallium/auxiliary/tgsi/tgsi_exec.c65
-rw-r--r--src/gallium/auxiliary/tgsi/tgsi_exec.h10
2 files changed, 65 insertions, 10 deletions
diff --git a/src/gallium/auxiliary/tgsi/tgsi_exec.c b/src/gallium/auxiliary/tgsi/tgsi_exec.c
index 1da04ab7e0..4a217454dd 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_exec.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_exec.c
@@ -1037,11 +1037,28 @@ fetch_source(
union tgsi_exec_channel index;
uint swizzle;
+ /* We start with a direct index into a register file.
+ *
+ * file[1],
+ * where:
+ * file = SrcRegister.File
+ * [1] = SrcRegister.Index
+ */
index.i[0] =
index.i[1] =
index.i[2] =
index.i[3] = reg->SrcRegister.Index;
+ /* There is an extra source register that indirectly subscripts
+ * a register file. The direct index now becomes an offset
+ * that is being added to the indirect register.
+ *
+ * file[ind[2].x+1],
+ * where:
+ * ind = SrcRegisterInd.File
+ * [2] = SrcRegisterInd.Index
+ * .x = SrcRegisterInd.SwizzleX
+ */
if (reg->SrcRegister.Indirect) {
union tgsi_exec_channel index2;
union tgsi_exec_channel indir_index;
@@ -1078,19 +1095,31 @@ fetch_source(
}
}
- if( reg->SrcRegister.Dimension ) {
- switch( reg->SrcRegister.File ) {
+ /* There is an extra source register that is a second
+ * subscript to a register file. Effectively it means that
+ * the register file is actually a 2D array of registers.
+ *
+ * file[1][3] == file[1*sizeof(file[1])+3],
+ * where:
+ * [3] = SrcRegisterDim.Index
+ */
+ if (reg->SrcRegister.Dimension) {
+ /* The size of the first-order array depends on the register file type.
+ * We need to multiply the index to the first array to get an effective,
+ * "flat" index that points to the beginning of the second-order array.
+ */
+ switch (reg->SrcRegister.File) {
case TGSI_FILE_INPUT:
- index.i[0] *= 17;
- index.i[1] *= 17;
- index.i[2] *= 17;
- index.i[3] *= 17;
+ index.i[0] *= TGSI_EXEC_MAX_INPUT_ATTRIBS;
+ index.i[1] *= TGSI_EXEC_MAX_INPUT_ATTRIBS;
+ index.i[2] *= TGSI_EXEC_MAX_INPUT_ATTRIBS;
+ index.i[3] *= TGSI_EXEC_MAX_INPUT_ATTRIBS;
break;
case TGSI_FILE_CONSTANT:
- index.i[0] *= 4096;
- index.i[1] *= 4096;
- index.i[2] *= 4096;
- index.i[3] *= 4096;
+ index.i[0] *= TGSI_EXEC_MAX_CONST_BUFFER;
+ index.i[1] *= TGSI_EXEC_MAX_CONST_BUFFER;
+ index.i[2] *= TGSI_EXEC_MAX_CONST_BUFFER;
+ index.i[3] *= TGSI_EXEC_MAX_CONST_BUFFER;
break;
default:
assert( 0 );
@@ -1101,6 +1130,17 @@ fetch_source(
index.i[2] += reg->SrcRegisterDim.Index;
index.i[3] += reg->SrcRegisterDim.Index;
+ /* Again, the second subscript index can be addressed indirectly
+ * identically to the first one.
+ * Nothing stops us from indirectly addressing the indirect register,
+ * but there is no need for that, so we won't exercise it.
+ *
+ * file[1][ind[4].y+3],
+ * where:
+ * ind = SrcRegisterDimInd.File
+ * [4] = SrcRegisterDimInd.Index
+ * .y = SrcRegisterDimInd.SwizzleX
+ */
if (reg->SrcRegisterDim.Indirect) {
union tgsi_exec_channel index2;
union tgsi_exec_channel indir_index;
@@ -1133,6 +1173,11 @@ fetch_source(
index.i[i] = 0;
}
}
+
+ /* If by any chance there was a need for a 3D array of register
+ * files, we would have to check whether SrcRegisterDim is followed
+ * by a dimension register and continue the saga.
+ */
}
swizzle = tgsi_util_get_full_src_register_extswizzle( reg, chan_index );
diff --git a/src/gallium/auxiliary/tgsi/tgsi_exec.h b/src/gallium/auxiliary/tgsi/tgsi_exec.h
index fc40a25e09..ac4b239910 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_exec.h
+++ b/src/gallium/auxiliary/tgsi/tgsi_exec.h
@@ -178,6 +178,16 @@ struct tgsi_exec_labels
#define TGSI_EXEC_MAX_LOOP_NESTING 20
#define TGSI_EXEC_MAX_CALL_NESTING 20
+/* The maximum number of input attributes per vertex. For 2D
+ * input register files, this is the stride between two 1D
+ * arrays.
+ */
+#define TGSI_EXEC_MAX_INPUT_ATTRIBS 17
+
+/* The maximum number of constant vectors per constant buffer.
+ */
+#define TGSI_EXEC_MAX_CONST_BUFFER 4096
+
/**
* Run-time virtual machine state for executing TGSI shader.
*/