Looking for AMD 29K User's Manual

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Hello,

I've download "Evaluating and Programming the 29K RISC Family" from
AMD's site, but they no longer provide the actual user's manual which
includes opcodes and more detailed instruction and execution
environment overviews.

I'm planning on emulating the 29000 and I believe I need more
information. The instruction descriptions in the document I have are
quite good but they don't include opcode numbers and I'm not sure
there is really enough information to do an accurate emulation.

If anyone has a PDF of the user's manual, please post here or get in
touch with me. If it's available only in hard copy and someone is
willing to part with their book, it would be very helpful to me :)

Thanks in advance!

Re: Looking for AMD 29K User's Manual
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Do you mean FPGA Core emulation, or SW emulation, or even code-morphing
on a P4 ?

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If you draw a blank on that, you could try
using a 29xxx Assembler and the test files, such as
http://john.ccac.rwth-aachen.de:8000/as /

 as also search to see what's  been done on FPGA Cores around
the 29xxx.
 It would seem that the latest FPGA iterations would suit a 29xxx
core.
 What's the tool-chain  status for 29xxx devices ?

-jg



Re: Looking for AMD 29K User's Manual
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Software emulation. I'm looking at a very old system which uses a 29K
as a math co-processor.

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Thanks. I'll be taking a look at this, it should be handy for testing.
I grabbed the GNU binutils sources which include a 29K disassembler,
so I now know the opcodes, but having the actual programming manual
would still be very useful.

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I'm not sure if the GNU tools are actively supporting it anymore. It's
not a problem for me since I'm not planning on writing any new 29K
code.

Re: Looking for AMD 29K User's Manual
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Isn't the 29000 a 4 bit ALU slice from about 1970, and in no way a
computer.  Or am I confusing things?

--
Chuck F ( snipped-for-privacy@yahoo.com) ( snipped-for-privacy@worldnet.att.net)
   Available for consulting/temporary embedded and systems.
We've slightly trimmed the long signature. Click to see the full one.
Re: Looking for AMD 29K User's Manual
"CBFalconer"
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The 2900/2901/2903 are the Bit Slice models.
Of course, someone COULD want to emulate that, in eg
a student project :)

The 29000 was rather different ( more of a jump than the add-a-digt 8086 ->
80186 :)
It was widely used in laser printers, for a while.

This from a web summary
The AMD 29000 family is a 32-bit RISC architecture introduced in 1988.
Notable characteristics include:
 192 registers divided into 64 global registers (gr64-gr127) and 128 local
registers (gr128-gr255)
 local registers form the top of a register stack that is backed by a larger
stack in memory
 access to local registers is relative to a register stack pointer (rsp =
gr1) and is calculated modulo 128
 a separate memory stack is provided for parameters beyond 16 words and for
parameters and local variables that must be memory allocated (i.e., for
which addresses are needed)
 procedure conventions for entry and exit includes register stack pointer
adjustment and software checks for underflow and overflow using assert
instructions that conditionally cause   traps
input parameters are passed in overlapped local registers, return values are
passed in global registers
a trace-back tag convention was defined for debuggers

-jg



Re: Looking for AMD 29K User's Manual
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That family was used in some 1984ish coin-op arcade games like Pole
Position II for graphics scaling.  (Driving games got expensive parts
because they could earn back the cost in a relatively short time.)  The
sound of over a dozen PP-IIs burning in at a time in attract mode will
haunt me almost as long as Tapper.  (Only one, but we spent some time
figuring out how they got such good sound out of their AY-3-8910s.  Those
tunes over and over...)

--
Ron Sharp.



Re: Looking for AMD 29K User's Manual
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Atari started using the 2901 long before that.  Battlezone used four of
them on the "math box" board back in 1980.  They were house-marked with
an Atari part number, and the schematics and service manual called them
out as "transistor arrays" (which is, of course, technically correct),
but when I first looked at the board it was immediately apparent that
they were bit slice chips, and most likely the 2901.  A quick look at
the pinout confirmed it.

Essentially the same "math box" was used for the games Red Baron and
Tempest.  In 1991 I wrote a disassembler for the math box firmware:
    http://www.brouhaha.com/~eric/software/mathdis /
This let to a math box simulator for the vector game simulator Hedley
Rannie and I wrote:
    http://www.brouhaha.com/~eric/software/vecsim /
These days, vecsim is of only historical interest (mainly for the crude
attempt at binary translation), but the math box simulation code lives
on in MAME.

On the original topic, Bob Henig and I ported the Telebit Netblazer
dialup router code from the 386 to the 29000 back in 1992.  I worked
on the OS kernel and device drivers.  It was interesting because the
29K normally uses TWO stacks for C code.

The 29K has a typical three-address RISC instruction set.  The register
addresses are eight bits each.  There are a few special registers numbered
in the 0x00-0x3f range, 64 global registers in the 0x40-0x7f range, and
128 local registers in the 0x80-0xff range.  However, any time a local
register is referenced, seven bits of one of the special registers are
added to the local register number as an offset (with wraparound).  This
is used to make the local registers act as a stack frame cache.

A stack frame cannot be larger than 128 registers total (including return
address, etc.).  When a non-leaf function is called, the function prologue
code determines whether there is enough space available in the stack frame
cache for the new stack frame, using an assert instruction.  If the assert
fails, the exception handler spills out one or more stack frames to memory
to make room.

Similarly, the function epilogue code checks whether the caller's stack
frame is entirely present in the stack frame cache using an assert
instruction.  If this assert fails, the exception handler fills the
frame in from memory.

The second stack arises because if a function needs more than 124 words
of local variables, it has to put the excess on an auxilliary stack.  It's
not possible to push extra words onto the main stack because it would
interfere with the spill/fill mechanism.

This makes context switching expensive.  And interrupt handling is
fairly complicated if you want to write your handler in C, because the
interrupt may have occurred during a function prologue or epilogue, in
which case the stack frame cache is in an inconsistent state.  AMD
published applicaitions information on how to fix this, but I used
a different technique involving switching to an interrupt stack and
setting the registers to make it look like the entire set of 128 local
registers are a single large stack frame.

Of course, it would be entirely possible for a compiler to treat the 29K
registers as a more conventional fixed arrangement simply by never setting
the offset.

Re: Looking for AMD 29K User's Manual
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I should have a complete set of documentation here *someplace*.
Of course, figuring out *which* place is the *trick*!  :-/   Undoubtedly,
stashed with my copy of Mick & Brick (wherever *that* went...)

I'll try to dig through the various boxes that it *may* be in sometime
over the holidays -- but don't get your hopes up...

--don

N.B. Incoming mail is not accepted at this email address.



Re: Looking for AMD 29K User's Manual
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Great, thanks! Email me if you do manage to find it. I'll probably get
started on it soon even without the user's manual. What I have now
should be enough to get a good deal of it done, but probably not all
of it.

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