GPU/Shader Instruction Set: Difference between revisions

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 Input attribute registers store the per-vertex data given by the CPU and hence are read-only.
-Output attribute registers hold the data to be passed to the later GPU stages and are write-only. Each of the output attribute register components is assigned a semantic by setting the corresponding [[GPU_Internal_Registers]]. Output registers o7-o15 are only available in vertex shaders.
+Output registers hold the data to be passed to the later GPU stages and are write-only. Each of the output register is assigned a semantic by setting the corresponding [[GPU_Internal_Registers]]. Output registers o7-o15 are only available in vertex shaders.
-It appears that writing twice to a component of an output register that was written to before can cause problems (e.g. GPU hangs).
+Keep in mind that writing to an output register that has been previously written to within 8 cycles of the first write appears to cause the GPU to hang. After 8 cycles, all further writes to an output register appear to be ignored and do not cause a GPU hang.
 Temporary registers can be used for intermediate calculations and can be both read and written.