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NetBSD/lib/libc/arch/i386/string/swab.S

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make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
/*
Winning Strategies has placed this code into the Public Domain
1995-04-29 02:53:59 +04:00
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
*/
Use RCSID macro for RCS ID's.
1994-03-12 04:39:55 +03:00
#include <machine/asm.h>
Change instances of LIBC_RCS back to LIBC_SCCS. If we are going to change th LIBC_RCS, the entire source tree should be updated at once. Remove && !defined(lint) from conditionals around rcs id's. No one is ever going to pass a *.s file through lint.
1993-10-21 04:39:55 +03:00
#if defined(LIBC_SCCS)
Use _ALIGN_TEXT from <machine/asm.h>.
1999-08-23 12:45:09 +04:00
RCSID("$NetBSD: swab.S,v 1.10 1999/08/23 08:45:11 kleink Exp $")
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
#endif
/*
* On the i486, this code is negligibly faster than the code generated
So many files in arch/i386 have been changed I might as well run my remove unecessary trailing whitespace script.
1993-10-21 04:48:14 +03:00
* by gcc at about half the size. If my i386 databook is correct, it
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
* should be considerably faster than the gcc code on a i386.
*/
ENTRY(swab)
pushl %esi
pushl %edi
movl 12(%esp),%esi
movl 16(%esp),%edi
movl 20(%esp),%ecx
cld # set direction forward
Remove special case for len == 0 --- It wasn't needed. By dropping the conditional, the general case (where we are actually swapping bytes) is a tiny bit faster.
1993-11-25 04:18:24 +03:00
shrl $1,%ecx
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
testl $7,%ecx # copy first group of 1 to 7 words
Remove special case for len == 0 --- It wasn't needed. By dropping the conditional, the general case (where we are actually swapping bytes) is a tiny bit faster.
1993-11-25 04:18:24 +03:00
jz L2 # while swaping alternate bytes.
Use _ALIGN_TEXT from <machine/asm.h>.
1999-08-23 12:45:09 +04:00
_ALIGN_TEXT,0x90
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
L1: lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
decl %ecx
testl $7,%ecx
Remove special case for len == 0 --- It wasn't needed. By dropping the conditional, the general case (where we are actually swapping bytes) is a tiny bit faster.
1993-11-25 04:18:24 +03:00
jnz L1
So many files in arch/i386 have been changed I might as well run my remove unecessary trailing whitespace script.
1993-10-21 04:48:14 +03:00
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
L2: shrl $3,%ecx # copy remainder 8 words at a time
jz L4 # while swapping alternate bytes.
Use _ALIGN_TEXT from <machine/asm.h>.
1999-08-23 12:45:09 +04:00
_ALIGN_TEXT,0x90
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
L3: lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
lodsw
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
rorw $8,%ax
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
stosw
decl %ecx
jnz L3
Use "ror $8,%ax" instead of "xchg %al,%ah": equal on a i386, 1 cycle faster on a i486, and 2 cycles faster on a iPentium.
1994-02-14 20:43:19 +03:00
L4: popl %edi
make an arch directory in libc, and move all machine dirs into it
1993-10-07 03:17:24 +03:00
popl %esi
ret