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authorGreg McGary <greg@mcgary.org>2000-06-09 06:14:39 +0000
committerGreg McGary <greg@mcgary.org>2000-06-09 06:14:39 +0000
commit3f02f778cdbec7d95e0a9d6f9368ce9cda0a6d03 (patch)
treea193d5f40640e64b7b6555e831772c1934e2a8d0 /sysdeps/i386/strchrnul.S
parenta40fb915f89d0e225058c0865de4504f83f90173 (diff)
* sysdeps/i386/bp-asm.h: New file.
* sysdeps/i386/__longjmp.S: Define & use symbolic argument stack offsets. Add ENTER/LEAVE macros for optionally maintaining frame-pointer chain when debugging. * sysdeps/i386/add_n.S: Likewise. * sysdeps/i386/addmul_1.S: Likewise. * sysdeps/i386/lshift.S: Likewise. * sysdeps/i386/memchr.S: Likewise. * sysdeps/i386/memcmp.S: Likewise. * sysdeps/i386/mul_1.S: Likewise. * sysdeps/i386/rawmemchr.S: Likewise. * sysdeps/i386/rshift.S: Likewise. * sysdeps/i386/stpcpy.S: Likewise. * sysdeps/i386/stpncpy.S: Likewise. * sysdeps/i386/strchr.S: Likewise. * sysdeps/i386/strchrnul.S: Likewise. * sysdeps/i386/strcspn.S: Likewise. * sysdeps/i386/strpbrk.S: Likewise. * sysdeps/i386/strrchr.S: Likewise. * sysdeps/i386/strspn.S: Likewise. * sysdeps/i386/strtok.S: Likewise. * sysdeps/i386/sub_n.S: Likewise. * sysdeps/i386/submul_1.S: Likewise. * sysdeps/i386/elf/setjmp.S: Likewise. * sysdeps/i386/i486/strcat.S: Likewise. * sysdeps/i386/i486/strlen.S: Likewise. * sysdeps/i386/i586/add_n.S: Likewise. * sysdeps/i386/i586/lshift.S: Likewise. * sysdeps/i386/i586/memcpy.S: Likewise. * sysdeps/i386/i586/memset.S: Likewise. * sysdeps/i386/i586/rshift.S: Likewise. * sysdeps/i386/i586/strchr.S: Likewise. * sysdeps/i386/i586/strcpy.S: Likewise. * sysdeps/i386/i586/strlen.S: Likewise. * sysdeps/i386/i586/sub_n.S: Likewise. * sysdeps/i386/i686/add_n.S: Likewise. * sysdeps/i386/i686/memcpy.S: Likewise. * sysdeps/i386/i686/mempcpy.S: Likewise. * sysdeps/i386/i686/memset.S: Likewise. * sysdeps/i386/i686/strcmp.S: Likewise. 2000-06-08 Greg McGary <greg@mcgary.org> * sysdeps/i386/bp-asm.h: New file. * sysdeps/i386/__longjmp.S: Define & use symbolic argument stack offsets. Add ENTER/LEAVE macros for optionally maintaining frame-pointer chain when debugging. * sysdeps/i386/add_n.S: Likewise. * sysdeps/i386/addmul_1.S: Likewise. * sysdeps/i386/lshift.S: Likewise. * sysdeps/i386/memchr.S: Likewise. * sysdeps/i386/memcmp.S: Likewise. * sysdeps/i386/mul_1.S: Likewise. * sysdeps/i386/rawmemchr.S: Likewise. * sysdeps/i386/rshift.S: Likewise. * sysdeps/i386/stpcpy.S: Likewise. * sysdeps/i386/stpncpy.S: Likewise. * sysdeps/i386/strchr.S: Likewise. * sysdeps/i386/strchrnul.S: Likewise. * sysdeps/i386/strcspn.S: Likewise. * sysdeps/i386/strpbrk.S: Likewise. * sysdeps/i386/strrchr.S: Likewise. * sysdeps/i386/strspn.S: Likewise. * sysdeps/i386/strtok.S: Likewise. * sysdeps/i386/sub_n.S: Likewise. * sysdeps/i386/submul_1.S: Likewise. * sysdeps/i386/elf/setjmp.S: Likewise. * sysdeps/i386/i486/strcat.S: Likewise. * sysdeps/i386/i486/strlen.S: Likewise. * sysdeps/i386/i586/add_n.S: Likewise. * sysdeps/i386/i586/lshift.S: Likewise. * sysdeps/i386/i586/memcpy.S: Likewise. * sysdeps/i386/i586/memset.S: Likewise. * sysdeps/i386/i586/rshift.S: Likewise. * sysdeps/i386/i586/strchr.S: Likewise. * sysdeps/i386/i586/strcpy.S: Likewise. * sysdeps/i386/i586/strlen.S: Likewise. * sysdeps/i386/i586/sub_n.S: Likewise. * sysdeps/i386/i686/add_n.S: Likewise. * sysdeps/i386/i686/memcpy.S: Likewise. * sysdeps/i386/i686/mempcpy.S: Likewise. * sysdeps/i386/i686/memset.S: Likewise. * sysdeps/i386/i686/strcmp.S: Likewise.
Diffstat (limited to 'sysdeps/i386/strchrnul.S')
-rw-r--r--sysdeps/i386/strchrnul.S53
1 files changed, 28 insertions, 25 deletions
diff --git a/sysdeps/i386/strchrnul.S b/sysdeps/i386/strchrnul.S
index f42a69728c..6860a11d7a 100644
--- a/sysdeps/i386/strchrnul.S
+++ b/sysdeps/i386/strchrnul.S
@@ -1,7 +1,7 @@
-/* strchrnul (str, ch) -- Return pointer to first occurrence of CH in STR
+/* strchrnul (str, chr) -- Return pointer to first occurrence of CHR in STR
or the final NUL byte.
For Intel 80x86, x>=3.
- Copyright (C) 1994, 1995, 1996, 1997, 1999 Free Software Foundation, Inc.
+ Copyright (C) 1994, 1995, 1996, 1997, 1999, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gnu.org>
Some optimisations by Alan Modra <Alan@SPRI.Levels.UniSA.Edu.Au>
@@ -23,22 +23,24 @@
#include <sysdep.h>
#include "asm-syntax.h"
+#include "bp-asm.h"
-/*
- INPUT PARAMETERS:
- str (sp + 4)
- ch (sp + 8)
-*/
+#define PARMS LINKAGE+4 /* space for 1 saved reg */
+#define RTN PARMS
+#define STR RTN+RTN_SIZE
+#define CHR STR+PTR_SIZE
.text
ENTRY (__strchrnul)
+ ENTER
+
pushl %edi /* Save callee-safe registers used here. */
- movl 8(%esp), %eax /* get string pointer */
- movl 12(%esp), %edx /* get character we are looking for */
+ movl STR(%esp), %eax
+ movl CHR(%esp), %edx
- /* At the moment %edx contains C. What we need for the
- algorithm is C in all bytes of the dword. Avoid
+ /* At the moment %edx contains CHR. What we need for the
+ algorithm is CHR in all bytes of the dword. Avoid
operations on 16 bit words because these require an
prefix byte (and one more cycle). */
movb %dl, %dh /* now it is 0|0|c|c */
@@ -108,9 +110,9 @@ ENTRY (__strchrnul)
into bit 32 (=carry flag), so all of the hole bits will
be changed.
- 3) But wait! Aren't we looking for C, not zero?
+ 3) But wait! Aren't we looking for CHR, not zero?
Good point. So what we do is XOR LONGWORD with a longword,
- each of whose bytes is C. This turns each byte that is C
+ each of whose bytes is CHR. This turns each byte that is CHR
into a zero. */
/* Each round the main loop processes 16 bytes. */
@@ -125,7 +127,7 @@ L(11): movl (%eax), %ecx /* get word (= 4 bytes) in question */
movl $0xfefefeff, %edi /* magic value */
addl %ecx, %edi /* add the magic value to the word. We get
carry bits reported for each byte which
- is *not* C */
+ is *not* CHR */
/* According to the algorithm we had to reverse the effect of the
XOR first and then test the overflow bits. But because the
@@ -144,7 +146,7 @@ L(11): movl (%eax), %ecx /* get word (= 4 bytes) in question */
incl %edi /* add 1: if one carry bit was *not* set
the addition will not result in 0. */
- /* If at least one byte of the word is C we don't get 0 in %edi. */
+ /* If at least one byte of the word is CHR we don't get 0 in %edi. */
jnz L(7) /* found it => return pointer */
/* Now we made sure the dword does not contain the character we are
@@ -169,8 +171,8 @@ L(11): movl (%eax), %ecx /* get word (= 4 bytes) in question */
movl $0xfefefeff, %edi /* magic value */
addl %ecx, %edi /* add the magic value to the word. We get
carry bits reported for each byte which
- is *not* C */
- jnc L(71) /* highest byte is C => return pointer */
+ is *not* CHR */
+ jnc L(71) /* highest byte is CHR => return pointer */
xorl %ecx, %edi /* ((word^charmask)+magic)^(word^charmask) */
orl $0xfefefeff, %edi /* set all non-carry bits */
incl %edi /* add 1: if one carry bit was *not* set
@@ -194,8 +196,8 @@ L(11): movl (%eax), %ecx /* get word (= 4 bytes) in question */
movl $0xfefefeff, %edi /* magic value */
addl %ecx, %edi /* add the magic value to the word. We get
carry bits reported for each byte which
- is *not* C */
- jnc L(72) /* highest byte is C => return pointer */
+ is *not* CHR */
+ jnc L(72) /* highest byte is CHR => return pointer */
xorl %ecx, %edi /* ((word^charmask)+magic)^(word^charmask) */
orl $0xfefefeff, %edi /* set all non-carry bits */
incl %edi /* add 1: if one carry bit was *not* set
@@ -219,8 +221,8 @@ L(11): movl (%eax), %ecx /* get word (= 4 bytes) in question */
movl $0xfefefeff, %edi /* magic value */
addl %ecx, %edi /* add the magic value to the word. We get
carry bits reported for each byte which
- is *not* C */
- jnc L(73) /* highest byte is C => return pointer */
+ is *not* CHR */
+ jnc L(73) /* highest byte is CHR => return pointer */
xorl %ecx, %edi /* ((word^charmask)+magic)^(word^charmask) */
orl $0xfefefeff, %edi /* set all non-carry bits */
incl %edi /* add 1: if one carry bit was *not* set
@@ -246,20 +248,20 @@ L(71): addl $4, %eax
But we have to take care of the case that a NUL char is
found before this in the dword. */
-L(7): testb %cl, %cl /* is first byte C? */
+L(7): testb %cl, %cl /* is first byte CHR? */
jz L(6) /* yes => return pointer */
cmpb %dl, %cl /* is first byte NUL? */
je L(6) /* yes => return NULL */
incl %eax /* it's not in the first byte */
- testb %ch, %ch /* is second byte C? */
+ testb %ch, %ch /* is second byte CHR? */
jz L(6) /* yes => return pointer */
cmpb %dl, %ch /* is second byte NUL? */
je L(6) /* yes => return NULL? */
incl %eax /* it's not in the second byte */
shrl $16, %ecx /* make upper byte accessible */
- testb %cl, %cl /* is third byte C? */
+ testb %cl, %cl /* is third byte CHR? */
jz L(6) /* yes => return pointer */
cmpb %dl, %cl /* is third byte NUL? */
je L(6) /* yes => return NULL */
@@ -269,7 +271,8 @@ L(7): testb %cl, %cl /* is first byte C? */
L(6): popl %edi /* restore saved register content */
- ret
+ LEAVE
+ RET_PTR
END (__strchrnul)
weak_alias (__strchrnul, strchrnul)