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author | Matt Turner <mattst88@gmail.com> | 2016-01-13 11:09:11 -0800 |
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committer | Matt Turner <mattst88@gmail.com> | 2016-01-14 09:28:01 -0800 |
commit | b82e26a6a4d6baf121f44c61c862bfa79ba0d172 (patch) | |
tree | d8c97faf241b7ea0bd07ceccde1f59f5e7058986 /src/glsl/nir/nir_opcodes.py | |
parent | 15640ee77ae601cba33cbbc72256e55e03a363e5 (diff) | |
download | external_mesa3d-b82e26a6a4d6baf121f44c61c862bfa79ba0d172.zip external_mesa3d-b82e26a6a4d6baf121f44c61c862bfa79ba0d172.tar.gz external_mesa3d-b82e26a6a4d6baf121f44c61c862bfa79ba0d172.tar.bz2 |
nir: Lower bitfield_extract.
The OpenGL specifications for bitfieldExtract() says:
The result will be undefined if <offset> or <bits> is negative, or if
the sum of <offset> and <bits> is greater than the number of bits
used to store the operand.
Therefore passing bits=32, offset=0 is legal and defined in GLSL.
But the earlier SM5 ubfe/ibfe opcodes are specified to accept a bitfield width
ranging from 0-31. As such, Intel and AMD instructions read only the low 5 bits
of the width operand, making them not able to implement the GLSL-specified
behavior directly.
This commit adds ubfe/ibfe operations from SM5 and a lowering pass for
bitfield_extract to to handle the trivial case of <bits> = 32 as
bitfieldExtract:
bits > 31 ? value : bfe(value, offset, bits)
Fixes:
ES31-CTS.shader_bitfield_operation.bitfieldExtract.uvec3_0
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92595
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Tested-by: Marta Lofstedt <marta.lofstedt@intel.com>
Diffstat (limited to 'src/glsl/nir/nir_opcodes.py')
-rw-r--r-- | src/glsl/nir/nir_opcodes.py | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/glsl/nir/nir_opcodes.py b/src/glsl/nir/nir_opcodes.py index 3e43438..e79810c 100644 --- a/src/glsl/nir/nir_opcodes.py +++ b/src/glsl/nir/nir_opcodes.py @@ -573,6 +573,37 @@ if (mask == 0) { } """) +# SM5 ubfe/ibfe assembly +opcode("ubfe", 0, tuint, + [0, 0, 0], [tuint, tint, tint], "", """ +unsigned base = src0; +int offset = src1, bits = src2; +if (bits == 0) { + dst = 0; +} else if (bits < 0 || offset < 0) { + dst = 0; /* undefined */ +} else if (offset + bits < 32) { + dst = (base << (32 - bits - offset)) >> (32 - bits); +} else { + dst = base >> offset; +} +""") +opcode("ibfe", 0, tint, + [0, 0, 0], [tint, tint, tint], "", """ +int base = src0; +int offset = src1, bits = src2; +if (bits == 0) { + dst = 0; +} else if (bits < 0 || offset < 0) { + dst = 0; /* undefined */ +} else if (offset + bits < 32) { + dst = (base << (32 - bits - offset)) >> (32 - bits); +} else { + dst = base >> offset; +} +""") + +# GLSL bitfieldExtract() opcode("ubitfield_extract", 0, tuint, [0, 0, 0], [tuint, tint, tint], "", """ unsigned base = src0; |