Initial commit: Go 1.23 release state

src/internal/bytealg/equal_arm64.s

@@ -0,0 +1,124 @@
+// 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"
+
+// memequal(a, b unsafe.Pointer, size uintptr) bool
+TEXT runtime·memequal<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-25
+	// short path to handle 0-byte case
+	CBZ	R2, equal
+	// short path to handle equal pointers
+	CMP	R0, R1
+	BEQ	equal
+	B	memeqbody<>(SB)
+equal:
+	MOVD	$1, R0
+	RET
+
+// memequal_varlen(a, b unsafe.Pointer) bool
+TEXT runtime·memequal_varlen<ABIInternal>(SB),NOSPLIT,$0-17
+	CMP	R0, R1
+	BEQ	eq
+	MOVD	8(R26), R2    // compiler stores size at offset 8 in the closure
+	CBZ	R2, eq
+	B	memeqbody<>(SB)
+eq:
+	MOVD	$1, R0
+	RET
+
+// input:
+// R0: pointer a
+// R1: pointer b
+// R2: data len
+// at return: result in R0
+TEXT memeqbody<>(SB),NOSPLIT,$0
+	CMP	$1, R2
+	// handle 1-byte special case for better performance
+	BEQ	one
+	CMP	$16, R2
+	// handle specially if length < 16
+	BLO	tail
+	BIC	$0x3f, R2, R3
+	CBZ	R3, chunk16
+	// work with 64-byte chunks
+	ADD	R3, R0, R6	// end of chunks
+chunk64_loop:
+	VLD1.P	(R0), [V0.D2, V1.D2, V2.D2, V3.D2]
+	VLD1.P	(R1), [V4.D2, V5.D2, V6.D2, V7.D2]
+	VCMEQ	V0.D2, V4.D2, V8.D2
+	VCMEQ	V1.D2, V5.D2, V9.D2
+	VCMEQ	V2.D2, V6.D2, V10.D2
+	VCMEQ	V3.D2, V7.D2, V11.D2
+	VAND	V8.B16, V9.B16, V8.B16
+	VAND	V8.B16, V10.B16, V8.B16
+	VAND	V8.B16, V11.B16, V8.B16
+	CMP	R0, R6
+	VMOV	V8.D[0], R4
+	VMOV	V8.D[1], R5
+	CBZ	R4, not_equal
+	CBZ	R5, not_equal
+	BNE	chunk64_loop
+	AND	$0x3f, R2, R2
+	CBZ	R2, equal
+chunk16:
+	// work with 16-byte chunks
+	BIC	$0xf, R2, R3
+	CBZ	R3, tail
+	ADD	R3, R0, R6	// end of chunks
+chunk16_loop:
+	LDP.P	16(R0), (R4, R5)
+	LDP.P	16(R1), (R7, R9)
+	EOR	R4, R7
+	CBNZ	R7, not_equal
+	EOR	R5, R9
+	CBNZ	R9, not_equal
+	CMP	R0, R6
+	BNE	chunk16_loop
+	AND	$0xf, R2, R2
+	CBZ	R2, equal
+tail:
+	// special compare of tail with length < 16
+	TBZ	$3, R2, lt_8
+	MOVD	(R0), R4
+	MOVD	(R1), R5
+	EOR	R4, R5
+	CBNZ	R5, not_equal
+	SUB	$8, R2, R6	// offset of the last 8 bytes
+	MOVD	(R0)(R6), R4
+	MOVD	(R1)(R6), R5
+	EOR	R4, R5
+	CBNZ	R5, not_equal
+	B	equal
+lt_8:
+	TBZ	$2, R2, lt_4
+	MOVWU	(R0), R4
+	MOVWU	(R1), R5
+	EOR	R4, R5
+	CBNZ	R5, not_equal
+	SUB	$4, R2, R6	// offset of the last 4 bytes
+	MOVWU	(R0)(R6), R4
+	MOVWU	(R1)(R6), R5
+	EOR	R4, R5
+	CBNZ	R5, not_equal
+	B	equal
+lt_4:
+	TBZ	$1, R2, lt_2
+	MOVHU.P	2(R0), R4
+	MOVHU.P	2(R1), R5
+	CMP	R4, R5
+	BNE	not_equal
+lt_2:
+	TBZ	$0, R2, equal
+one:
+	MOVBU	(R0), R4
+	MOVBU	(R1), R5
+	CMP	R4, R5
+	BNE	not_equal
+equal:
+	MOVD	$1, R0
+	RET
+not_equal:
+	MOVB	ZR, R0
+	RET