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How the Famicom Was Born

How the Famicom Was Born
by on (#146942)
How the Famicom Was Born:

http://www.glitterberri.com/developer-i ... -was-born/

Folks curious about system design details might enjoy Part 7. No, there is not "tons" of technical insights, but there are general insights/thought processes/desires/goals.

I won't be reading this thread from here on out because I can safely predict what will happen. ;-)
Re: How the Famicom Was Born
by on (#146943)
Quote:
The system’s development code name was the GAMECOM.

Kind of like this? :lol:

Image

I don't know about you, but I though I heard that the Famicom was originally supposed to be a really high end machine at first, but that they lowered the specifications a good bit to make it affordable. Maybe I'm just imagining this...

If the article is right, I think it's a bit funny how much the people fussed about having to use the 6502 instead of the Z80. Where they writing in machine code at that point?
Re: How the Famicom Was Born
by on (#146945)
Espozo wrote:
If the article is right, I think it's a bit funny how much the people fussed about having to use the 6502 instead of the Z80. Where they writing in machine code at that point?


It's a bit more complicated than that. Both processors have their own way of doing things, such as indirect or indexed addressing. On the z80, you have to do pointer math, but on the 6502, you just need an index, or you need to store the pointer in ZP and index from there, or store the calculated pointer in ZP and remember to set X or Y to zero, and the fact that X and Y do different types of indexing in certain circumstances.

Basically, all the optimizations you know from the Z80 are rendered meaningless. Switching to a new processor that nobody is familiar with is a significant setback in development time since everyone needs to learn how to use it. Thank goodness Kato was there to help out and speed things along.
Re: How the Famicom Was Born
by on (#146968)
Espozo wrote:
I don't know about you, but I though I heard that the Famicom was originally supposed to be a really high end machine at first, but that they lowered the specifications a good bit to make it affordable. Maybe I'm just imagining this...


I think you are thinking of the Super Famicom.
Re: How the Famicom Was Born
by on (#146969)
mikejmoffitt wrote:
Espozo wrote:
I don't know about you, but I though I heard that the Famicom was originally supposed to be a really high end machine at first, but that they lowered the specifications a good bit to make it affordable. Maybe I'm just imagining this...


I think you are thinking of the Super Famicom.

Probably. If they used top of the line in 1986, it would have still been good in 1990/1991, but it would still have costed alot. I wonder how far the SNES could have gone with another $50. (I still think Neo Geo level graphics could have been made using $300, but the main thing going for the Neo Geo was the CHR rom, even if of course it also had powerful video hardware.) To be fair though, The SNES is about on the same level technically as most arcade hardware from 1986 that I've seen.
Re: How the Famicom Was Born
by on (#146971)
Espozo wrote:
If the article is right, I think it's a bit funny how much the people fussed about having to use the 6502 instead of the Z80. Where they writing in machine code at that point?

Japanese companies were accustomed to the Z80, if I recall correctly nobody else over there was using the 6502 at the time. That brought in quiet some trouble with tools and such.
Re: How the Famicom Was Born
by on (#146994)
The 6502-based Commodore PET & VIC-20 actually boosted the 6502's standing in Japan... one of the former Japanese Commodore users club members was Satoru Iwata, who programmed Commodore games, then went on to HAL, and later Nintendo where he is now president of the company.
Re: How the Famicom Was Born
by on (#147012)
HAL themselves also wrote several Commodore-published games, like the VIC-20 version of Rally-X

Code:
THIS PROGRAM WAS
   WRITTEN BY
- HIROAKI SUGA -
  APR. 9, 1981
 HAL LABORATORY
  TOKYO, JAPAN


and the VIC-20 and C64 versions of Jupiter Lander, which (IIRC) was the first C64 game ever released. So there were a few 6502 programmers in Japan before the NES, at least :P
Re: How the Famicom Was Born
by on (#147018)
It's interesting. At first, the argument that they would use a 6502 instead of a Z80 to prevent reverse engineering sounds like a joke, but they really were thinking it. (Unsurprisingly it failed miserably).

By designing their own CPU (like the did for the Game Boy or the CICs for example) it would have been a much more efficient strategy to get in the way of reverse engineering.
Re: How the Famicom Was Born
by on (#147023)
Bregalad wrote:
It's interesting. At first, the argument that they would use a 6502 instead of a Z80 to prevent reverse engineering sounds like a joke, but they really were thinking it. (Unsurprisingly it failed miserably).

I guess they figured everyone would make as big of a fuss as them. :roll:

Bregalad wrote:
By designing their own CPU (like the did for the Game Boy or the CICs for example) it would have been a much more efficient strategy to get in the way of reverse engineering.

How much of a Z80 is the Gameboy Z80 anyway? What's different? (I think somebody told me, but I forgot.)
Re: How the Famicom Was Born
by on (#147036)
The DMG and Z80 are largely the same, there are a few opcodes that are different though; the inclusion of a zeropage-like memory access, removal of the IN/OUT opcodes, and removal of the block copy functionality.
Re: How the Famicom Was Born
by on (#147042)
Didn't they also remove some registers (index registers?) and the instructions that used these registers? That's a big enough change to force Z80 programmers to change their way of doing things.
Re: How the Famicom Was Born
by on (#147048)
Yeah, although IX and IY are rather slow (slower than immediate addresses, in fact).

Bregalad wrote:
It's interesting. At first, the argument that they would use a 6502 instead of a Z80 to prevent reverse engineering sounds like a joke, but they really were thinking it. (Unsurprisingly it failed miserably).

Ricoh seemed more interested on the "takes up a quarter of the die that the Z80 would need" part, anyway (since it meant being able to cram in way more stuff).
Re: How the Famicom Was Born
by on (#147052)
Sharp, on the other hand, was more like "Gordon Moore told us that five years later you can fit ten times as much stuff into each square millimeter."
Re: How the Famicom Was Born
by on (#147059)
Sik wrote:
Ricoh seemed more interested on the "takes up a quarter of the die that the Z80 would need" part, anyway (since it meant being able to cram in way more stuff).

You can tell they didn't have the NES in mind when they were designing the Famicom... (About half of the console is the cartridge slot.)
Re: How the Famicom Was Born
by on (#147090)
Except the chip still would have taken up the same amount of space on the board. In fact, you can't make the die larger because then you risk it becoming too fragile and breaking up. So yeah, reducing space usage on the die was quite important.

For the record, on Z80-based systems usually the Z80 was discrete anyway. It was the rest of the hardware that would be custom instead (if not off-the-shelf too, that is - e.g. SG-1000 was entirely off-the-shelf parts).