Re: Instruction Tracing

On 2024-08-10 21:57, John Levine wrote:

It appears that Lawrence D'Oliveiro  <ldo@nz.invalid> said:

(ROMP was also one of those RISC architectures that had delayed branches,
along with MIPS, HP-PA and I think SPARC as well.)
>
I have heard it said that the RT PC was a poor advertisement for the
benefits of RISC, and the joke was made that “RT” stood for “Reduced
Technology”.

 I worked on AIX for the RT/PC. It was a pretty reasonable chip for the
time, but it suffered greatly from internal IBM political fights which
made it too little too late. AIX ran on top of a bloated virtual
machine which made the whole thing too slow. There was skunkworks port
of BSD that was supposed to be a lot better.
 As far as the delayed branches and such, they made sense in the narrow
time window when it was too expensive to put a cache on a workstation
but that time came and went by the time the RT shipped.

A long time ago, I heard (or maybe read) that the original ROMP was chopped in half (the FP stuff was removed) by orders of marketing for some sort of h/w word-processor.  When that product bombed and the workstation market blossomed, the engineers "bolted" the FP stuff back on.  I cannot find the source.  Is there any truth to this?
OF