Shader Linking

In order to pass data between the vertex and fragment shader, a sort of link-program seems to be copying from the output of the vertex shader into the TRAM (the RAM used as input to rasterization and shading).

This program is located at offset 0x300 and upwards, and seems to have 64-bit words. Here's an example:

0x00000008
0x0000fecd

This copies four floats from each vertex.

The first word seems to contain the location to copy from in the vertex shader, the latter word contains the location in the fragment shader.

The latter word contains the following for single varyings (for a simple dot product-shader):

datatype	value	var instruction
lowp float	00b7	00400000
mediump float	000f	00800000
lowp vec2	00b7	00800000
mediump vec2	00fe	00408000
lowp vec3	b7a6	00810000
mediump vec3	0dfe	00408100
lowp vec4	a6b7	00810000
mediump vec4	cdfe	00408102

In addition to this, something is going on at offset 0xe20 and upwards:

0x58000000