Am 26.03.2013 15:56, schrieb Michel Dänzer:
On Die, 2013-03-26 at 14:51 +0100, Christian König wrote:
From: Christian König <christian.koe...@amd.com>
Signed-off-by: Christian König <christian.koe...@amd.com>
[...]
diff --git a/src/gallium/drivers/radeonsi/radeonsi_shader.h
b/src/gallium/drivers/radeonsi/radeonsi_shader.h
index 9dae742..e09f297 100644
--- a/src/gallium/drivers/radeonsi/radeonsi_shader.h
+++ b/src/gallium/drivers/radeonsi/radeonsi_shader.h
@@ -111,13 +111,18 @@ struct si_shader {
unsigned nr_cbufs;
};
-struct si_shader_key {
- unsigned export_16bpc:8;
- unsigned nr_cbufs:4;
- unsigned color_two_side:1;
- unsigned alpha_func:3;
- unsigned flatshade:1;
- float alpha_ref;
+union si_shader_key {
+ struct {
+ unsigned export_16bpc:8;
+ unsigned nr_cbufs:4;
+ unsigned color_two_side:1;
+ unsigned alpha_func:3;
+ unsigned flatshade:1;
+ float alpha_ref;
+ } ps;
+ struct {
+ unsigned instance_divisors[PIPE_MAX_ATTRIBS];
+ } vs;
};
This grows the shader key from 8 to 128 bytes. I don't suppose the
instance divisors could be encoded in a more compact way? E.g. loading
the divisor values from constants and only tracking which elements use a
divisor in a bitmask in the key.
Considered that also, and I have two problems with that approach:
1. While immediates are converted to shifts & muls, dividing even by a
constant in the shader isn't cheap.
2. I couldn't get the reciprocal instruction working on the first try
(ok you fixed that).
How about storing only a byte for the instance_divisor? That limit's the
divisor to a modulo of 256, but I don't think that would be so extremly
bad. That would reduce the key to 32 bytes instead.
Christian.
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