In directx, if reuse a slot does gpu keep previous resource in its memory? Also can original processor resources be safely altered?

I was writing this question about directx and the following questions were part of it, but I realized I needed to separate them out.

If something isn't in a "slot" (register) on the GPU, will it have to be retransferred to the GPU to be used again, i.e. if put texture A in register t0, then later put texture B in register t0, is texture t0 no longer available on the GPU? Or is it still resident in the GPU memory, but I will have to place a call to load it into a texture register to get at it? Or something else entirely?

In a similar vein do calls to PSSetShaders, or PSSetShaderResource, or IASetVertexBuffers, etc.... block and copy data to the GPU before returning, so after the call one can alter or even free the resources they were based on because it is now resident on the GPU?

I guess this is more than one question, but I expect I'll get trouble if I try asking too many directx questions in one day (thought I think these are honestly decent questions about whi开发者_StackOverflowch the msdn documentation remains pretty silent, even if they are all newbie questions).

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if put texture A in regsiter t0, then later put texture B in register t0, is texture t0 no longer available on the GPU?

It is no longer bound to the texture register so will not get applied to any polygons. You will have to bind it to a texture register again to use it.

Or is it still resident in the GPU memory, but I will have to place a call to load it into a texture register to get at it?

Typically they will stay in video memory until enough other resources have been loaded in that it needs to reclaim the memory. This was more obvious in DirectX 9 when you had to specify which memory pool to place resource in. Now everything is effectively in what was the D3DPOOL_MANAGED memory pool in Direct3D 9. When you set the texture register to use the texture it will be fast as long as the textures is still in video memory.

In a similar vein do calls to PSSetShaders, or PSSetShaderResource, or IASetVertexBuffers, etc.... block and copy data to the GPU before returning, so after the call one can alter or even free the resources they were based on because it is now resident on the GPU?

DirectX manages the resources for you and tries to keep them in video memory as long as it can.