bjt wrote:I guess there will need to be a more general solution for the Tandy sound card, like a PM TSR that traps all these things and redirects Tandy sound writes.
bjt wrote:It doesn't use the Tandy string, but the Machine ID byte
carlostex wrote:bjt wrote:I guess there will need to be a more general solution for the Tandy sound card, like a PM TSR that traps all these things and redirects Tandy sound writes.
As far as i know the Tandy Sound Card approach was to place the sound chip on C0h / 1E0h selectable with a jumper. From what i could understand the last few months i launched the Tandy thread, a TSR is great for interrupt interception but not to read a memory location.
In fact i think having the hardware sit directly on the proper locations is the best approach. It should work great on XT systems (and theoretically it shouldn't be a problem on AT's as well) and no need for software that will require a 386.
For games that DO require to read the TANDY string there's 2 choices: either patch the games like you did or place the TANDY string at the proper location, creating a BIOS extension to do so, like 2M-XBIOS does vias the DOS prompt.
I went as far as changing the Tandy ROM BIOS and changing the string from TANDY to DANDY via hex editing on location F000:C078 and it was not a surprise games that rely on that string started to play PC Speaker music and having monochrome graphics.bjt wrote:It doesn't use the Tandy string, but the Machine ID byte
Can you tell me the exact memory location of the byte?
Great Hierophant wrote:Just checking the BIOS area for the ASCII "TANDY" will not suffice on its own to identify a Tandy 1000 compatible machine.
Super Boulder Dash (from Electronic Arts) contains CGA, PCjr and Tandy executables that can be extracted. The Prism Software versions run under DOS but do not include a Tandy executable.perhaps we can get a patched version of boulderdash too? I never got the booter-version that can be patched? to work.
carlostex wrote:Great Hierophant wrote:Just checking the BIOS area for the ASCII "TANDY" will not suffice on its own to identify a Tandy 1000 compatible machine.
Depends on the game/program. Some might require one or the other or in some cases both. In fact, i changed the machine byte from 21 to 22 (on ASCII hexadecimal 21 is '!') and AGI games still detect Tandy machine just fine. Now try to change the TANDY ASCII to something else and you'll see the difference, no Tandy graphics and no Tandy 3 voice sound. This or maybe PCem sucks at emulating a Tandy but keep in mind it uses a real Tandy ROM image.
I also tried Maniac Mansion and this one unlike AGI games desn't give a crap about the TANDY ASCII string or should i say the bytes: 54 61 6E 64 79 that start at F000:C078. It does however care about the 21 hex byte at FC00 and changing it to anything else will result in 4 color graphics and beeper sound. The AGI games is the complete opposite. They do not care about the single byte at FC00 but they do care about the 5 bytes at F000:C078.
Great Hierophant wrote:The AGI games may be conducting graphics adapter tests in addition to using the TANDY string. Late versions of the interpreter will display the games on an EGA or VGA card if installed in the Tandy, which disables the built-in TGA. However, Sierra explicitly advertised their games as working on the Tandy 1200, an XT clone, the Tandy 3000 and 4000, which were using 286s and 386s. Those systems must have the copyright string somewhere in their BIOS.
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