Which ones? I'm genuinely curious about this.
Those are all quite old now of course, but even modern GPUs may not have 64-bit ALUs and rely on emulation instead. Intel Gen11 in Ice Lake, for example: https://01.org/sites/default/files/documentation/intel-gfx-p...
In mobile architectures 64-bit ALUs can be an optional feature that is omitted for lower end configurations. I know this is true of PowerVR.
Those are all quite old now of course, but even modern GPUs may not have 64-bit ALUs and rely on emulation instead. Intel Gen11 in Ice Lake, for example: https://01.org/sites/default/files/documentation/intel-gfx-p...
In mobile architectures 64-bit ALUs can be an optional feature that is omitted for lower end configurations. I know this is true of PowerVR.