GLSL in software mode

Dear openglProgrammers,

How to run a shader(GLSL) program in software mode.Is there any feature similar to D3DDEVTYPE_HAL/D3DDEVTYPE_REF in DirectX which tells the system to do Hardware/software rendering

Thanks in advance

You could try Mesa. It provides OpenGL implementation in software. You will be able to run not only GLSL, but also ARB shaders and fixed-function pipeline in software mode.

Try NVemulate for all Nvidia cards.
I can force software and emulate all gpu generations.