You're right: many of TecToy's Brazil-exclusive Master System games were tweaked versions of Game Gear releases. That includes games like Ecco 2, Mortal Kombat 3 and Sonic Blast, but not the aforementioned Street Fighter II which they developed independently.
I think the Master System version of Sonic Spinball came from Sega themselves though. It was sold in Europe as well as Brazil.
I don't know if they even had an emulator at the time - I don't think a 1980s PC could run a NES emulator at a reasonable speed.
Another possibility is that they used a hardware device. Perhaps something that watches the 6502 `sync` pin to know when an opcode byte is being read, and verifies that the data bus contains a legal value.
> On execution, 16-bit Thumb instructions are transparently decompressed to full 32-bit ARM instructions in real time, without performance loss.
That quote is from the ARM7TDMI manual - the CPU used in the Game Boy Advance, for example. I believe later processors contained entirely separate ARM and Thumb decoders.
Throughout the entire NES game library, almost no games use these illegal opcodes. Apparently as part of the licensing process, Nintendo would verify that games only used the official instructions.
I wonder how they tested that, though? I don't think developers had to submit their source code to Nintendo, so they would have had to analyse the binaries in some way?
Nice and compact! When I was writing a Z80 emulator I made heavy use of the tables in Sean Young's "The Undocumented Z80 Documented" [0] (chapters 8, 9 & 10). This 2-page reference card seems to contain just about everything in the document's 22 pages.
Instruction timings are in the pink table on the left-hand side. For example, `ADC HL, BC; ED4A; H15` means that the instruction affects the flags as in row H and takes 15 cycles to execute.
> Sony’s part number suggests it has a 45 inch tube inside. But in a rare case of truth in advertising, Sony advertised it as a 43-inch model.
The overall tube size is 45”, the actual screen size is 43”. I believe it was mandatory in the USA to market TVs based on screen size, in most of the rest of the world they were sold based on tube size.
That’s why common sizes of 4:3 CRT TV in the US were 13/20/24/27/32” whereas in the rest of the world the same size TVs were sold as 14/21/25/29/34”. Interestingly the tubes’ internal part numbers are based on the screen size in centimeters: 34/51/59/68/80 cm.
According to [0], about 1.2 kg (2.6 lbs). Surprisingly this is mostly in the neck and funnel of the tube - the screen itself uses different metals because lead would affect its optical performance.
Yes, the aperture grille (hundreds of wires and a metal frame holding them in tension) is itself heavier than a traditional shadow mask.
However, aperture grilles also use differently-shaped glass from shadow masks. The screens are only curved horizontally like a cylinder rather than on both axes like a sphere. This requires thicker, heavier glass to hold the vacuum.
Later flat-glass shadow-mask tubes were much closer in weight to flat Trinitrons.
AFAIK the French NES is just a PAL console with an added composite-to-RGB converter. Although it outputs RGB signals, the quality is no better than composite.
The Sega Genesis did something similar - its hardware is a strict superset of the Master System's, so it can run SMS games natively.
However, unlike the Game Boy and GBA, the cartridge ports on the two systems are physically different (50 pins vs 64) so a cartridge adapter is still needed.
In that situation, I think an approach like the Super Game Boy's is probably better: include the old console's hardware in the adapter rather than in the new console, so that the new console's design need not be constrained by backward-compatibility.
> A megabyte of ram on a machine with only a 16 bit address space gets a bit silly. Do you really want to manage 16 memory pages?
The Game Boy Color has a 16-bit address space and almost all its games are 1MB or larger (although that's ROM rather than RAM). The largest game is 8MB in size - which is managed as 512 banks of 16KB each.
It doesn't sound like they include the entire ROM, only the parts necessary to play back the recording. If you "take control", the game may try to access parts of the ROM which are missing, which causes the quote to reset. This happens frequently with the Metroid II example - the Tetris one seems much more robust.
The Game Boy is much more similar to the Sega Master System & Game Gear than to the NES. Some games (e.g. Lemmings 2, Pinball Dreams, Spirou) were developed for both handhelds (or even for all 3 platforms) using a single assembly-language codebase.
> In reality, every monitor was a CRT. They just drew what looked good on their development devices.
True, but there was a huge difference between a good-quality RGB monitor and a consumer TV connected via composite video or RF. Ideally designers would have been using development devices that took that difference into account.
For example, I've heard of artists at Sega drawing on PCs and using custom hardware so they could simultaneously view their work on a real Genesis connected to a typical TV.
I think the Master System version of Sonic Spinball came from Sega themselves though. It was sold in Europe as well as Brazil.