On Thu, Oct 22, 2015 at 9:40 AM, Elardus Engelbrecht <
[email protected]> wrote:
> John McKown wrote:
>
> >Mainly that the compiler inserted an NOPR 0 after my simple command.
>
> Hmmm, I remembered that Borland Turbo Pascal [1] could do that similar
> trick, but I don't have MSDOS and Pascal anymore.
>
> I never tried that [inserting machine code to speed up things] out with C
> and C++.
>
> > *000004 0700 9 NOPR 0
> > 000074 581D 00B0 000009 | L r1,176(r13,)
>
> Is that compiler action just for [full word / half word?] alignment?
> Increase/decrease the instruction length by 1 or 2 bytes with same or other
> instruction and see where it ends up.
>
Hum, I inserted a second instruction "LR 2,1" after the first one:
000009 | * __asm(" L 1,%0\n LR
2,1":"=m"(i3)::"r1","r2");
*000000 581D 00B0 000B0 8 L 1,176(13)
000009
*000004 1821 9 LR 2,1
000009
*000006 0700 10 NOPR 0
000009
000074 581D 00B0 000009 | L r1,176(r13,)
000078 1821 000009 | LR r2,r1
00007A 0700 000009 | NOPR 0
000010 | * printf("%.*s\n",i1,word);
The NOPR is still there. I wonder if it is somehow used if I were to set a
break point in a debugging session. I.e. the NOPR is there so that it can
be overlain with the debug SVC or whatever is used.
I'm just doing this to see if I can get up to the real desire: to embed
assembler macros, such as TPG (TSO terminal I/O), in my C code. Although
it might actually be simpler to just continue writing LE enabled HLASM
"service" routines.
Hum, wish I had a way to make an HLASM "program" which could be "in
lined" by the C compiler in order to avoid the entry/exit code overhead. I
am still, perhaps stupidly, concerned with "CPU overhead". If I weren't I
could be a Windows programmer! <grin type="snide"/>
>
> >This is just curiosity on my part. It is not a "bug" or a complaint.
>
> This is why we all need you. You learn on the hard way and we look on the
> easy way. ;-D
>
> Groete / Greetings
> Elardus Engelbrecht
>
> [1] - I wrote cryptographic code in mix of Turbo Pascal and MASM to
> protect my and my clients files. Good old MSDOS days when nothing was
> available for pure protection.
>
>
--
Schrodinger's backup: The condition of any backup is unknown until a
restore is attempted.
Yoda of Borg, we are. Futile, resistance is, yes. Assimilated, you will be.
He's about as useful as a wax frying pan.
10 to the 12th power microphones = 1 Megaphone
Maranatha! <><
John McKown
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