Lionel Sambuc 0a6a1f1d05 NetBSD re-synchronization of the source tree
This brings our tree to NetBSD 7.0, as found on -current on the
10-10-2015.

This updates:
 - LLVM to 3.6.1
 - GCC to GCC 5.1
 - Replace minix/commands/zdump with usr.bin/zdump
 - external/bsd/libelf has moved to /external/bsd/elftoolchain/
 - Import ctwm
 - Drop sprintf from libminc

Change-Id: I149836ac18e9326be9353958bab9b266efb056f0
2016-01-13 20:32:14 +01:00

48 lines
816 B
ArmAsm

/*
* Written by J.T. Conklin <jtc@NetBSD.org>.
* Public domain.
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS)
RCSID("$NetBSD: swab.S,v 1.4 2014/05/22 15:01:57 uebayasi Exp $")
#endif
#define LOAD_SWAP_STORE_WORD \
lodsw ; \
xchgb %al,%ah ; \
stosw
ENTRY(swab)
xchgq %rdi,%rsi
cld # set direction forward
shrq $1,%rdx
testq $7,%rdx # copy first group of 1 to 7 words
jz L2 # while swapping alternate bytes.
L1: lodsw
rorw $8,%ax
stosw
decq %rdx
testq $7,%rdx
jnz L1
L2: shrq $3,%rdx # copy remainder 8 words at a time
jz L4 # while swapping alternate bytes.
L3:
LOAD_SWAP_STORE_WORD
LOAD_SWAP_STORE_WORD
LOAD_SWAP_STORE_WORD
LOAD_SWAP_STORE_WORD
LOAD_SWAP_STORE_WORD
LOAD_SWAP_STORE_WORD
LOAD_SWAP_STORE_WORD
LOAD_SWAP_STORE_WORD
decq %rdx
jnz L3
L4:
ret
END(swab)