2019-02-21 06:40
ChanServ changed the topic of ##yamahasynths to: Channel dedicated to questions and discussion of Yamaha FM Synthesizer internals and corresponding REing. Discussion of synthesis methods similar to the Yamaha line of chips, Sound Blasters + clones, PCM chips like RF5C68, and CD theory of operation are also on-topic. Channel logs:
https://freenode.irclog.whitequark.org/~h~yamahasynths
01:42
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andlabs >
"such as the Genesis version of Star Cruiser on Genesis" oops
01:42
<
andlabs >
I make this mistake more often than I'd like to admit
01:46
<
andlabs >
brb rebooting
01:47
<
andlabs >
also you may want to look at the 68000 user's maunal too
01:47
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andlabs >
NOT the M68000PRM
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03:13
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sorear >
huh, they actually got rid of instructions in the 68060!?
03:26
<
TD-Linux >
examples of machines with BERR attached include the x68000. it implements a timeout
03:26
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TD-Linux >
cr1901_modern, things like the mega drive use 68000 synchronous mode. see the 68000 datasheet
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05:56
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andlabs >
sorear: I can't confirm but it's likely the FPU is the 68040's incomplete FPU implementation
05:57
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andlabs >
or allegedly incomplete
05:57
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sorear >
you mean they didn't get rid of instructions on purpose, they just ran out of time to make it compatible?
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19:26
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cr1901_modern >
I thought the 68060 was never released?
19:27
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andlabs >
no it was
19:27
<
andlabs >
it just didn't make it to many consumer devices
19:28
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andlabs >
overshadowed by the launch of the PowerPC platform
19:28
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andlabs >
sorear: compare the M68000PRM to the 68060 manual to see what is or isn't there
19:29
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andlabs >
the M68000PRM has both the 688881/2 (standalone FPU) manuals and teh 68040 integrated FPU manual
19:29
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andlabs >
under the section on floating-point opcodes
19:35
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andlabs >
for instnace there's this M68040FPSP thing that I don't know what it is
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20:08
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andlabs >
the 68040 has a subset of the 6888X FPU ISA
20:08
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andlabs >
the missing instructions have to do with trigonometry and logarithms
20:08
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andlabs >
so they were also privded as a "floating-point software package"
20:09
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andlabs >
this is an example of something that would use the infamous LINE 1111 EMULATOR vector
20:11
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andlabs >
here's a modified version included with the RTEMS operating system
20:24
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andlabs >
68040 hardware FPU opcodes: FABS, FADD, FBcc, FCMP, FDBcc, FDIV, FMOVE, FMOVEM, FMUL, FNEG, FNOP, FScc, FSGLDIV, FSGLMUL, FSQRT, FSUB, FTRAPcc, FTST, FRESTORE, FSAVE
23:18
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cr1901_modern >
Was the 68888 FPU less weird than the 8087 (rotating register window/"stack")?
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