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optimize 16- and 32-bit moves

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function                                             old     new   delta
udhcpd_main                                         1239    1257     +18
udhcp_add_simple_option                               93      92      -1
buffer_read_le_u32                                    19      18      -1
unpack_gz_stream_with_info                           526     520      -6
dnsd_main                                           1470    1463      -7
udhcp_run_script                                    1208    1186     -22
send_ACK                                             255     229     -26
arping_main                                         1661    1623     -38
send_offer                                           470     428     -42
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/8 up/down: 18/-143)          Total: -125 bytes
This commit is contained in:
Denis Vlasenko
2008-12-08 22:56:18 +00:00
parent d1a84a2880
commit efb545b9bd
13 changed files with 97 additions and 77 deletions
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12
include/platform.h
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@ -151,13 +151,19 @@
/* ---- Unaligned access ------------------------------------ */
/* parameter is supposed to be an uint32_t* ptr */
/* NB: unaligned parameter should be a pointer, aligned one -
* a lvalue. This makes it more likely to not swap them by mistake
*/
#if defined(i386) || defined(__x86_64__)
#define get_unaligned_u32p(u32p) (*(u32p))
#define move_from_unaligned16(v, u16p) ((v) = *(uint16_t*)(u16p))
#define move_from_unaligned32(v, u32p) ((v) = *(uint32_t*)(u32p))
#define move_to_unaligned32(u32p, v) (*(uint32_t*)(u32p) = (v))
/* #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; })
#define move_from_unaligned16(v, u16p) (memcpy(&(v), (u16p), 2))
#define move_from_unaligned32(v, u32p) (memcpy(&(v), (u32p), 4))
#define move_to_unaligned32(u32p, v) (memcpy((u32p), &(v), 4))
#endif
/* ---- Networking ------------------------------------------ */