27 Jan
1999
27 Jan
'99
6:06 a.m.
You're absolutely correct . . . I actually got out my old AMD MOS
Microprocessors and Peripherals data book from 1985, and found that the
9511 is a stack oriented (like the HP calculators, I guess) arithmetic
processor capable of 16 and 32-bit floating point operations, while the
9512 is capable of 32 and 64-bit operations.
The 9511, it seems is capable of many more functions, being somewhat
reminiscent of a "scientific" calculator, while the 9512 is capable of none
of the transcendental functions which the 9511 supports. Both are
stack-oriented, therefore ideal for RPN implementation.
My steel-trap mind moves closer and closer every day to being a sievel . .
oh, well . . . it's HELL getting old.
Dick
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From: Gary Oliver <go(a)ao.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Subject: Re: AMD 9511, 9512, Intel 8231, 8232 wanted,
will tradeNational
MM57109
Date: Wednesday, January 27, 1999 12:36 PM
integer
From my copy of "Floating Point Program
Manual Am9511A/Am9512:"
Am9511A Arithmetic Processor
Distinctive Characteristics
---------------------------
2,3 and 4 MHz operation
Fixed point 16 bit and 32 bit operations
Floating point 32 bit operations
Binary data formats
Add, Subtract, Multiply and Divide
Trigonometric and inverse trigonometric functions
Square roots, logarithms, exponentiation
Stack-oriented operand storage
...
Am9512 Floating Point Processor
Distinctive Characteristics
---------------------------
Single (32-bit) and double (64-bit) precision capability
Add, Subtract, Multiply and Divide
Compatible with proposed IEEE format
...
The 9511 is very much like a calculator with a 32 bit operand
stack of up to four items. Operations work on the top or top
two items on the stack. Some operands (such as PUPI "push PI")
push a new item on the stack.
At 4Mhz, a FADD takes (worst case) about 92 uSec and an FMUL
(worst case) at 42 uSeconds. Wasn't too shabby when software
took 5 to 10 times as long on a Z-80. Plus it was possible to
get some other work done while the 9511 was off crunching a
number or two.
We still use the 9511 on an old (very old) legacy product, although
they will eventually disappear - AMD is certainly not making them
anymore and there are very few left on distributor shelves or even
in "part surplus" houses.
Gary
At 10:18 AM 1/27/99 -0700, you wrote:
>The 9511 was the floating point unit, and the 9512 was for 64-bit >arithmetic, I believe. I've actually got one
of each of these from back
in
>the old days. They were sort of a calculator for
your computer, in that
>they could be operated faster than the cpu could perform the function .
.
MUCH faster.
Dick
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