resash of X-windows and 3b1/7300's

[Mike Haertel]

In article <2070 at umbc3.UMBC.EDU> mark at umbc3.umbc.edu.UMBC.EDU (Mark Sienkiewicz) writes:
>2 - expect a bitmap of the screen to appear in the address space of
>a user process.  This would involve either a spy at CT or a really
>clever kernel hacker to find out how to work the paging stuff in the kernel.

Due to brain damaged design of the hardware it is actually impossible
to map the video memory into user process space.  I have written programs
that directly access video memory, but they only run standalone.

>- you are limited in CPU power.  You would gain a *** LOT *** of performance
>by changing all the 32 bit operations to 16 bit operations.  This is a lot
>of work which would probably be left out of a first stab at it.

Only multiplications should be downgraded.  Bitwise operations especially
should be done in 32 bits.  However, due to brain damaged design, if you
want to do screen ops in 32 bit words you have to swap them (the screen
is wordwise little endian but bytewise big endian).  But it is faster to
swap all loads and stores from or to video memory than it is to do
everything in 16 bits.
-- 
Mike Haertel <mike at stolaf.edu>
"There's nothing remarkable about it.  All one has to do is hit the right
 keys at the right time and the instrument plays itself." -- J. S. Bach