/* wcsrchr with SSE2, without using bsf instructions.
   Copyright (C) 2011-2026 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#if IS_IN (libc)
# include <sysdep.h>
# define CFI_PUSH(REG)	\
	cfi_adjust_cfa_offset (4);	\
	cfi_rel_offset (REG, 0)

# define CFI_POP(REG)	\
	cfi_adjust_cfa_offset (-4);	\
	cfi_restore (REG)

# define PUSH(REG)	pushl REG; CFI_PUSH (REG)
# define POP(REG)	popl REG; CFI_POP (REG)

# define PARMS	8
# define ENTRANCE	PUSH (%edi);
# define RETURN	POP (%edi); ret; CFI_PUSH (%edi);
# define STR1	PARMS
# define STR2	STR1+4

	atom_text_section
ENTRY (__wcsrchr_sse2)

	ENTRANCE
	mov	STR1(%esp), %ecx
	movd	STR2(%esp), %xmm1

	mov	%ecx, %edi
	punpckldq %xmm1, %xmm1
	pxor	%xmm2, %xmm2
	punpckldq %xmm1, %xmm1

/* ECX has OFFSET. */
	and	$63, %ecx
	cmp	$48, %ecx
	ja	L(crosscache)

/* unaligned string. */
	movdqu	(%edi), %xmm0
	pcmpeqd	%xmm0, %xmm2
	pcmpeqd	%xmm1, %xmm0
/* Find where NULL is.  */
	pmovmskb %xmm2, %ecx
/* Check if there is a match.  */
	pmovmskb %xmm0, %eax
	add	$16, %edi

	test	%eax, %eax
	jnz	L(unaligned_match1)

	test	%ecx, %ecx
	jnz	L(return_null)

	and	$-16, %edi

	PUSH	(%esi)

	xor	%edx, %edx
	jmp	L(loop)

	CFI_POP	(%esi)

	.p2align 4
L(unaligned_match1):
	test	%ecx, %ecx
	jnz	L(prolog_find_zero_1)

	PUSH	(%esi)

/* Save current match */
	mov	%eax, %edx
	mov	%edi, %esi
	and	$-16, %edi
	jmp	L(loop)

	CFI_POP	(%esi)

	.p2align 4
L(crosscache):
/* Hancle unaligned string.  */
	and	$15, %ecx
	and	$-16, %edi
	pxor	%xmm3, %xmm3
	movdqa	(%edi), %xmm0
	pcmpeqd	%xmm0, %xmm3
	pcmpeqd	%xmm1, %xmm0
/* Find where NULL is.  */
	pmovmskb %xmm3, %edx
/* Check if there is a match.  */
	pmovmskb %xmm0, %eax
/* Remove the leading bytes.  */
	shr	%cl, %edx
	shr	%cl, %eax
	add	$16, %edi

	test	%eax, %eax
	jnz	L(unaligned_match)

	test	%edx, %edx
	jnz	L(return_null)

	PUSH	(%esi)

	xor	%edx, %edx
	jmp	L(loop)

	CFI_POP	(%esi)

	.p2align 4
L(unaligned_match):
	test	%edx, %edx
	jnz	L(prolog_find_zero)

	PUSH	(%esi)

	mov	%eax, %edx
	lea	(%edi, %ecx), %esi

/* Loop start on aligned string.  */
	.p2align 4
L(loop):
	movdqa	(%edi), %xmm0
	pcmpeqd	%xmm0, %xmm2
	add	$16, %edi
	pcmpeqd	%xmm1, %xmm0
	pmovmskb %xmm2, %ecx
	pmovmskb %xmm0, %eax
	or	%eax, %ecx
	jnz	L(matches)

	movdqa	(%edi), %xmm3
	pcmpeqd	%xmm3, %xmm2
	add	$16, %edi
	pcmpeqd	%xmm1, %xmm3
	pmovmskb %xmm2, %ecx
	pmovmskb %xmm3, %eax
	or	%eax, %ecx
	jnz	L(matches)

	movdqa	(%edi), %xmm4
	pcmpeqd	%xmm4, %xmm2
	add	$16, %edi
	pcmpeqd	%xmm1, %xmm4
	pmovmskb %xmm2, %ecx
	pmovmskb %xmm4, %eax
	or	%eax, %ecx
	jnz	L(matches)

	movdqa	(%edi), %xmm5
	pcmpeqd	%xmm5, %xmm2
	add	$16, %edi
	pcmpeqd	%xmm1, %xmm5
	pmovmskb %xmm2, %ecx
	pmovmskb %xmm5, %eax
	or	%eax, %ecx
	jz	L(loop)

	.p2align 4
L(matches):
	test	%eax, %eax
	jnz	L(match)
L(return_value):
	test	%edx, %edx
	jz	L(return_null_1)
	mov	%edx, %eax
	mov	%esi, %edi

	POP	(%esi)

	test	%ah, %ah
	jnz	L(match_third_or_fourth_wchar)
	test	$15 << 4, %al
	jnz	L(match_second_wchar)
	lea	-16(%edi), %eax
	RETURN

	CFI_PUSH	(%esi)

	.p2align 4
L(return_null_1):
	POP	(%esi)

	xor	%eax, %eax
	RETURN

	CFI_PUSH	(%esi)

	.p2align 4
L(match):
	pmovmskb %xmm2, %ecx
	test	%ecx, %ecx
	jnz	L(find_zero)
/* save match info */
	mov	%eax, %edx
	mov	%edi, %esi
	jmp	L(loop)

	.p2align 4
L(find_zero):
	test	%cl, %cl
	jz	L(find_zero_in_third_or_fourth_wchar)
	test	$15, %cl
	jz	L(find_zero_in_second_wchar)
	and	$1, %eax
	jz	L(return_value)

	POP	(%esi)

	lea	-16(%edi), %eax
	RETURN

	CFI_PUSH	(%esi)

	.p2align 4
L(find_zero_in_second_wchar):
	and	$1 << 5 - 1, %eax
	jz	L(return_value)

	POP	(%esi)

	test	$15 << 4, %al
	jnz	L(match_second_wchar)
	lea	-16(%edi), %eax
	RETURN

	CFI_PUSH	(%esi)

	.p2align 4
L(find_zero_in_third_or_fourth_wchar):
	test	$15, %ch
	jz	L(find_zero_in_fourth_wchar)
	and	$1 << 9 - 1, %eax
	jz	L(return_value)

	POP	(%esi)

	test	%ah, %ah
	jnz	L(match_third_wchar)
	test	$15 << 4, %al
	jnz	L(match_second_wchar)
	lea	-16(%edi), %eax
	RETURN

	CFI_PUSH	(%esi)

	.p2align 4
L(find_zero_in_fourth_wchar):

	POP	(%esi)

	test	%ah, %ah
	jnz	L(match_third_or_fourth_wchar)
	test	$15 << 4, %al
	jnz	L(match_second_wchar)
	lea	-16(%edi), %eax
	RETURN

	CFI_PUSH	(%esi)

	.p2align 4
L(match_second_wchar):
	lea	-12(%edi), %eax
	RETURN

	.p2align 4
L(match_third_or_fourth_wchar):
	test	$15 << 4, %ah
	jnz	L(match_fourth_wchar)
	lea	-8(%edi), %eax
	RETURN

	.p2align 4
L(match_third_wchar):
	lea	-8(%edi), %eax
	RETURN

	.p2align 4
L(match_fourth_wchar):
	lea	-4(%edi), %eax
	RETURN

	.p2align 4
L(return_null):
	xor	%eax, %eax
	RETURN

	.p2align 4
L(prolog_find_zero):
	add	%ecx, %edi
	mov     %edx, %ecx
L(prolog_find_zero_1):
	test	%cl, %cl
	jz	L(prolog_find_zero_in_third_or_fourth_wchar)
	test	$15, %cl
	jz	L(prolog_find_zero_in_second_wchar)
	and	$1, %eax
	jz	L(return_null)

	lea	-16(%edi), %eax
	RETURN

	.p2align 4
L(prolog_find_zero_in_second_wchar):
	and	$1 << 5 - 1, %eax
	jz	L(return_null)

	test	$15 << 4, %al
	jnz	L(match_second_wchar)
	lea	-16(%edi), %eax
	RETURN

	.p2align 4
L(prolog_find_zero_in_third_or_fourth_wchar):
	test	$15, %ch
	jz	L(prolog_find_zero_in_fourth_wchar)
	and	$1 << 9 - 1, %eax
	jz	L(return_null)

	test	%ah, %ah
	jnz	L(match_third_wchar)
	test	$15 << 4, %al
	jnz	L(match_second_wchar)
	lea	-16(%edi), %eax
	RETURN

	.p2align 4
L(prolog_find_zero_in_fourth_wchar):
	test	%ah, %ah
	jnz	L(match_third_or_fourth_wchar)
	test	$15 << 4, %al
	jnz	L(match_second_wchar)
	lea	-16(%edi), %eax
	RETURN

END (__wcsrchr_sse2)
#endif
