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authorGravatar Denis Vlasenko <vda.linux@googlemail.com>2008-06-27 03:55:18 +0000
committerGravatar Denis Vlasenko <vda.linux@googlemail.com>2008-06-27 03:55:18 +0000
commit42b8daf88a600289d6b72c52777183ef64b05bb0 (patch)
tree7a213fa6c8779f28f8befa6257c3fa9b0f960c33 /include/platform.h
parentdefc1ea34074e7882724c460260d307cdf981a70 (diff)
downloadbusybox-42b8daf88a600289d6b72c52777183ef64b05bb0.tar.gz
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expand comment about FAST_FUNC
Diffstat (limited to 'include/platform.h')
-rw-r--r--include/platform.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/include/platform.h b/include/platform.h
index 8d6ed9a3e..fe68547f0 100644
--- a/include/platform.h
+++ b/include/platform.h
@@ -97,9 +97,15 @@
# endif
#endif
+/* FAST_FUNC is a qualifier which (possibly) makes function call faster
+ * and/or smaller by using modified ABI. It is usually only needed
+ * on non-static, busybox internal functions. Recent versions of gcc
+ * optimize statics automatically. FAST_FUNC on static is required
+ * only if you need to match a function pointer's type */
#if __GNUC_PREREQ(3,0) && defined(i386)
/* || defined(__x86_64__)? */
# define FAST_FUNC __attribute__((regparm(3)))
+/* #elif ... - add your favorite arch today! */
#else
# define FAST_FUNC
#endif
@@ -145,8 +151,9 @@
/* ---- Unaligned access ------------------------------------ */
/* parameter is supposed to be an uint32_t* ptr */
-#if defined(i386) || defined(__x86_64__) /* + other arches? */
+#if defined(i386) || defined(__x86_64__)
#define get_unaligned_u32p(u32p) (*(u32p))
+/* #elif ... - add your favorite arch today! */
#else
/* performs reasonably well (gcc usually inlines memcpy here) */
#define get_unaligned_u32p(u32p) ({ uint32_t __t; memcpy(&__t, (u32p), 4); __t; })