View Single Post
Old 22 June 2004, 15:06   #9
IFW
Moderator
IFW's Avatar
 
Join Date: Jan 2003
Location: ...
Age: 45
Posts: 1,838
"doesn't clr.w do a R/W ?!?"

Correct.
On the 68000 cpu clr is indeed an rmw instruction, and hence performs a read/write operation on the same address, causing the strobe address of $dff088 being accessed twice.
move #0, $dff088 is safer, though hitting the strobe twice normally wouldn't cause any problems, apart from bad practice. The future compatibility of the hardware system is not an issue anymore, so no worries
On the 68020 clr is fine, it only writes.
IFW is offline  
 
Page generated in 0.04695 seconds with 9 queries