nes
nes

Some cleanup.  Decompose push_s and pop_s.  Add bus usage comments for all decode logic.  Formatting.

[git-p4: depot-paths = "//depot/hw/nes/": change = 102]

timofonic/fpga_nes,gtaylormb/fpga_nes,brianbennett/fpga_nes,timofonic/fpga_nes,gtaylormb/fpga_nes,brianbennett/fpga_nes,gtaylormb/fpga_nes,timofonic/fpga_nes,brianbennett/fpga_nes