- Jun 8, 2019
I think I would get this just for Blazing Lazers, Soldier Blade, Super Star Solider, and Salamander. I don't think I played the other shooters in the list, but I'm sure they are awesome and thus a huge bonus for me too. Why the hell did this console manage to get so many shooters but the SNES hardly any? I know the SNES had a shit CPU (which I assume is the main reason it didn't get many), but it had to be at least marginally better than the cpu in the TG16/PC Engine.
It depends on the code you were running - both CPUs are designed around the same basic 6502 architecture and are connected to an 8 bit bus. The 65816 in the SNES has 16 bit registers and a 16 bit ALU - but 16 bit memory operations were slow because they had to be handled in two memory cycles. The result of this was that in most code 16 bit mode was used only when it was necessary, and the CPU ran in 8 bit mode whenever possible. The PC Engine CPU only had the 8 bit mode - but it was also clocked much higher (about twice as fast as the SNES in "fast ROM" mode) - so when running code that was dealing entirely with 8 bit data it was much faster. Conversely the SNES CPU was much faster for code that was doing lots of 16 bit operations and performing limited or no external memory access.
The other difference is that the PC Engine CPU - although basically a 6502 - was heavily customized. It had an on-chip memory mapper to get around the 64K addressing limitation and some extra instructions - some of these were just instruction set extensions (like bit manipulation and testing) and others were more specific - for example, there were special instructions that wrote literal values to the VDP registers so you didn't have to load the value into A and then write it out to a 16 bit direct mode address (which would be much slower). It also had memory transfer instructions - including one (TIA) that that appears to have been designed specifically to copy blocks of data from system RAM or ROM to the VDP with a single instruction.
There are also some large architectural differences in the video hardware - the SNES has up to 4 background layers (although most games used less due to the color depth limitations in the 4 BG mode) - the PCE has a single BG layer, but more palettes. There is also lots of scope for cheating on the PCE because you can write VRAM during active display time (this obviously burns a lot of CPU time).
One standout feature of the SNES is the ability to apply a matrix transform to the entire screen (in mode 7 only) - there is no equivalent feature on the PCE, and it would be far to computationally expensive to fake it.