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| author | Eric Anholt <eric@anholt.net> | 2010-09-08 17:49:10 -0700 |
|---|---|---|
| committer | Eric Anholt <eric@anholt.net> | 2010-09-08 18:05:22 -0700 |
| commit | e04f90712d8e04ce9d2fee46d0cccf818432c7d9 (patch) | |
| tree | 280343322dfd7136202a7cb8696d86b63db68933 /src/glsl/README | |
| parent | d8ab9aac54c3b6e4d97016172527d4b7c85b27a2 (diff) | |
| download | external_mesa3d-e04f90712d8e04ce9d2fee46d0cccf818432c7d9.zip external_mesa3d-e04f90712d8e04ce9d2fee46d0cccf818432c7d9.tar.gz external_mesa3d-e04f90712d8e04ce9d2fee46d0cccf818432c7d9.tar.bz2 | |
glsl: Update README talking about multi-instruction operations.
The previous thing taking multiple instructions ended up being handled
at the IR level, as we suggested would be the common result. Pick a
new one.
Diffstat (limited to 'src/glsl/README')
| -rw-r--r-- | src/glsl/README | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/glsl/README b/src/glsl/README index 2e501d6..7e97b48 100644 --- a/src/glsl/README +++ b/src/glsl/README @@ -156,10 +156,10 @@ for the 965 fragment shader backend when that is developed. Q: How should I expand instructions that take multiple backend instructions? Sometimes you'll have to do the expansion in your code generation -- -see, for example, ir_to_mesa.cpp's handling of ir_binop_mul for -matrices. However, in many cases you'll want to do a pass over the IR -to convert non-native instructions to a series of native instructions. -For example, for the Mesa backend we have ir_div_to_mul_rcp.cpp because +see, for example, ir_to_mesa.cpp's handling of ir_unop_sqrt. However, +in many cases you'll want to do a pass over the IR to convert +non-native instructions to a series of native instructions. For +example, for the Mesa backend we have ir_div_to_mul_rcp.cpp because Mesa IR (and many hardware backends) only have a reciprocal instruction, not a divide. Implementing non-native instructions this way gives the chance for constant folding to occur, so (a / 2.0) |