register-impoverished childhoods was Re: Z80 TRAP and CP/M

[jim stephens]

Cameron Kaiser wrote:

>>E.g., if you are writing code for a 68xx, you have little choice
>>but to do everything in memory addressing.
>>    
>>
>
>Or a 6502. I don't know what to *do* with all the other registers on
>other architectures. ^_^;;
>
>  
>
if there are enough of them, you should be able to use them as memory.

on the Microdata 1600, when it was first put out, one of the criticisms 
of the design
was that the design had an 8 x 32 static ram that was used as, god 
forbid, a register
file, with a 4 bit selector, for 30 registers.  This was up from the 
800's design which
had only 1 file bank, of 15 registers.  one of the complaints was that 
the 0 register
was special, and did not use the file's location 0 (or 16).

now days it is nothing to throw away an entire register to emit a 0 or 1 
constant, but
then it was scandalous waste of hardware.  (69- 71)

Jim