They did have SDKs (well, an assembler and linker) as well as devkits and extensive documentation. The problem was you had to enter an extensive agreement and p

They did have SDKs (well, an assembler and linker) as well as devkits and extensive documentation. The problem was you had to enter an extensive agreement and pay a hefty amount for the privilege of using them. It made sense in that era, as you had to have the cash on hand to order a minimum of 10,000 cartridges (also manufactured by Nintendo) anyway.