Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754804AbZLFCEJ (ORCPT ); Sat, 5 Dec 2009 21:04:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752811AbZLFCEG (ORCPT ); Sat, 5 Dec 2009 21:04:06 -0500 Received: from mail-px0-f174.google.com ([209.85.216.174]:63657 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752613AbZLFCEG (ORCPT ); Sat, 5 Dec 2009 21:04:06 -0500 From: Justin Madru To: gregkh@suse.de Cc: linux-kernel@vger.kernel.org, Justin Madru Subject: [PATCH] staging: s5k3e2fx.c: reduce complexity by factoring Date: Sat, 5 Dec 2009 18:03:20 -0800 Message-Id: <1260065000-5573-1-git-send-email-jdm64@gawab.com> X-Mailer: git-send-email 1.6.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1948 Lines: 59 I was style fixing some code when I ran into this code. It seems like the code could be reduced, by factoring the expression. But this results in a very simple expression. Am I assuming something wrong? Or is this a bug in the original code? This doesn't look right because the assignment of s_move[i] has no mention of the loop counter. Justin ------ the code was looping, seting s_move[i] to the following calculations if (actual_step >= 0) s_move[i] = ((((i + 1) * gain + 0x200) - (i * gain + 0x200)) / 0x400); else s_move[i] = ((((i + 1) * gain - 0x200) - (i * gain - 0x200)) / 0x400); but, by factoring the expression, it can be shown that they both reduce to a very simple expression: s_move[i] = gain / 0x400; Signed-off-by: Justin Madru --- drivers/staging/dream/camera/s5k3e2fx.c | 10 +++------- 1 files changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/staging/dream/camera/s5k3e2fx.c b/drivers/staging/dream/camera/s5k3e2fx.c index f0e49be..d205a2d 100644 --- a/drivers/staging/dream/camera/s5k3e2fx.c +++ b/drivers/staging/dream/camera/s5k3e2fx.c @@ -1092,14 +1092,10 @@ static int32_t s5k3e2fx_move_focus(int direction, int32_t num_steps) actual_step = step_direction * (int16_t)num_steps; pos_offset = init_code + s5k3e2fx_ctrl->curr_lens_pos; - gain = actual_step * 0x400 / 5; + gain = actual_step / 5; - for (i = 0; i <= 4; i++) { - if (actual_step >= 0) - s_move[i] = ((((i+1)*gain+0x200) - (i*gain+0x200))/0x400); - else - s_move[i] = ((((i+1)*gain-0x200) - (i*gain-0x200))/0x400); - } + for (i = 0; i <= 4; i++) + s_move[i] = gain; /* Ring Damping Code */ for (i = 0; i <= 4; i++) { -- 1.6.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/