From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Mon, 19 Mar 2007 16:04:11 +0000 (-0000)
Subject: expand documentation
X-Git-Tag: 1_5_1~22
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=3d101dd4670e449a064bd8ea88d5343d83144f49;p=oweals%2Fbusybox.git

expand documentation
---

diff --git a/docs/keep_data_small.txt b/docs/keep_data_small.txt
index 66f92b321..fcd8df4a9 100644
--- a/docs/keep_data_small.txt
+++ b/docs/keep_data_small.txt
@@ -125,3 +125,32 @@ less readable, use #defines:
 If applet doesn't use much of global data, converting it to use
 one of above methods is not worth the resulting code obfuscation.
 If you have less than ~300 bytes of global data - don't bother.
+
+
+		gcc's data alignment problem
+
+The following attribute added in vi.c:
+
+static int tabstop;
+static struct termios term_orig __attribute__ ((aligned (4)));
+static struct termios term_vi __attribute__ ((aligned (4)));
+
+reduced bss size by 32 bytes, because gcc sometimes aligns structures to
+ridiculously large values. asm output diff for above example:
+
+ tabstop:
+        .zero   4
+        .section        .bss.term_orig,"aw",@nobits
+-       .align 32
++       .align 4
+        .type   term_orig, @object
+        .size   term_orig, 60
+ term_orig:
+        .zero   60
+        .section        .bss.term_vi,"aw",@nobits
+-       .align 32
++       .align 4
+        .type   term_vi, @object
+        .size   term_vi, 60
+
+gcc doesn't seem to have options for altering this behaviour.