Re: [patch 3/2] drivers/char/vt.c: remove unnecessary code

[colbuse@ensisun.imag.fr]

Surlignage Russell King <rmk+lkml@arm.linux.org.uk>:

> On Mon, Feb 28, 2005 at 02:13:57PM +0100, colbuse@ensisun.imag.fr wrote:
> > NPAR times :-). As I stated, npar is unsigned.
> 
> I think that's disgusting then - it isn't obvious what's going on, which
> leads to mistakes.
> 
> For the sake of a micro-optimisation such as this, it's far more important
> that the code be readable and easily understandable.
> 
> Others may disagree.
> 

I agree :) . But, if we look to the code, we can notice that there is actually
no reason for npar to be unsigned. What do you think of this version?


--- old/drivers/char/vt.c       2004-12-24 22:35:25.000000000 +0100
+++ new/drivers/char/vt.c       2005-02-28 12:53:57.933256631 +0100
@@ -1655,9 +1655,9 @@
                        vc_state = ESnormal;
                return;
        case ESsquare:
-               for(npar = 0 ; npar < NPAR ; npar++)
+               for(npar = NPAR - 1; npar >= 0; npar--)
                        par[npar] = 0;
+               npar++;
-               npar = 0;
                vc_state = ESgetpars;
                if (c == '[') { /* Function key */
                        vc_state=ESfunckey;


--- old/include/linux/console_struct.h  2004-12-24 22:33:48.000000000 +0100
+++ old/include/linux/console_struct.h  2005-02-28 14:49:53.653616335 +0100
@@ -44,7 +44,8 @@
        unsigned short  vc_video_erase_char;    /* Background erase character */
        /* VT terminal data */
        unsigned int    vc_state;               /* Escape sequence parser state */
-       unsigned int    vc_npar,vc_par[NPAR];   /* Parameters of current escape
sequence */
+       unsigned int    vc_par[NPAR];           /* Parameters of current escape
sequence */
+       int             vc_npar;                /* Current position in vc_par */
        struct tty_struct *vc_tty;              /* TTY we are attached to */
        /* mode flags */
        unsigned int    vc_charset      : 1;    /* Character set G0 / G1 */


--
Emmanuel Colbus
Club GNU/Linux
ENSIMAG - Departement telecoms


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