// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include "go_asm.h"
#include "textflag.h"

TEXT ·IndexByte(SB),NOSPLIT,$0-20
	MOVW	b_base+0(FP), R0
	MOVW	b_len+4(FP), R1
	MOVBU	c+12(FP), R2	// byte to find
	MOVW	$ret+16(FP), R5
	B	indexbytebody<>(SB)

TEXT ·IndexByteString(SB),NOSPLIT,$0-16
	MOVW	s_base+0(FP), R0
	MOVW	s_len+4(FP), R1
	MOVBU	c+8(FP), R2	// byte to find
	MOVW	$ret+12(FP), R5
	B	indexbytebody<>(SB)

// input:
//  R0: data
//  R1: data length
//  R2: byte to find
//  R5: address to put result
TEXT indexbytebody<>(SB),NOSPLIT,$0-0
	MOVW	R0, R4		// store base for later
	ADD	R0, R1		// end

loop:
	CMP	R0, R1
	B.EQ	notfound
	MOVBU.P	1(R0), R3
	CMP	R2, R3
	B.NE	loop

	SUB	$1, R0		// R0 will be one beyond the position we want
	SUB	R4, R0		// remove base
	MOVW	R0, (R5)
	RET

notfound:
	MOVW	$-1, R0
	MOVW	R0, (R5)
	RET