1. Re: Waiting for a retrace.. again
I just now tried the wait_retrace code I sent and discovered that it is
agonizingly slow. Panning the screen was pretty jerky using that
procedure. So then I whipped out my assembly language cheat sheet and
coded it in machine language. Its much faster and smoother now. I
think a lot of time was lost in polling Jacques Deschenes Input
procedure. Though this may not be significant on any machine better
than my 486/50.
---- code begins ----
constant wait_retrace_code = {
#50, -- PUSH EAX
#52, -- PUSH EDX
#BA,#DA,3,0,0,-- MOV EDX, 0x03DA
#EC, -- IN AL, DX
#24,#08, -- AND AL, 0x08
#75,#FB, -- JNZ $-5
#EC, -- IN AL, DX
#24,#08, -- AND AL, 0x08
#74,#FB, -- JZ $-5
#5A, -- POP EDX
#58, -- POP EAX
#C3 } -- RET
global atom wait_retrace
wait_retrace = allocate(length(wait_retrace_code))
poke(wait_retrace, wait_retrace_code)
---- code ends ----
wait_retrace isn't a procedure anymore.
it must be called using "call(wait_retrace)"
Hope this helps
Pete Eberlein <xseal at harborside.com>
