According to Peter:
Function InPortW ( port: Integer ) result: ShortWord; begin (* InPortW *) asm ( 'inw %%dx, %%ax' : '=a' ( result ) : 'd' ( port ) ); end (* InPortW *); Function InPortB ( port: Integer ) result: Byte; begin (* InPortB *) asm ( 'inw %%dx, %%al' : '=a' ( result ) : 'd' ( port ) ); end (* InPortB *);(NOT TESTED, sorry!) PredatorZeta, are you sure that it's `inw' in the second case, not `inb'?
Thanks Peter for your bugfixes to my procedures! I know, I'm very absent-minded in these days..."inw" it's because I cute and paste in Rhide the first proc!!! BTW, here it's occasion to explain two things (heheheh):
1)_The reserved word "result" ISN'T explained properly in the info documentation. (at least in my version!!???). It work, but with this stupid warning:
Warning: return value of function not assigned
I think because GPC can't consider the Asm assignment as a real assignment....
2)_The code outputted from your proc with -O2 switch activated is:
1 pushl %ebp 2 movl %esp,%ebp 3 subl $12,%esp 4 movl %ecx,-4(%ebp) 5 movl 8(%ebp),%edx /APP 6 inb %dx, %al /NOAPP 7 movb %al,-5(%ebp) 8 movb -5(%ebp),%al | 9 leave 10 ret
=8-||||| AAAAAAAARRRRGGGHHH!!!8-)) Whatta the lines 7 and 8 do?????? NOTHING!!! If I cutout these lines the code works IDeNtIcAL!! Also this cost >3< clock cycles on Pentium, for the AGI stall...
PredatorZeta, are you sure that it's `inw' in the second case, not `inb'?
Uhhmmmm....OKK, This is my fault:))))))))))))
BTW, you can even use these as procedures in your program without loss
of
speed: With full optimization `-O3', GPC will automatically inline the above.
Trust me, with these macro: {$DEFINE Inportw(port,myvar) Asm("inw %%dx, %%ax" : "=a" (myvar) : "d" (port))} {$DEFINE Inportb(port,myvar) Asm("inb %%dx, %%al" : "=a" (myvar) : "d" (port))}
the code works without useless MOVs, and it's inlined with or without -O3.8-))))))
Cya...