// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: BSD-3-Clause

#include "textflag.h"

// func add(a, b int64) int64
TEXT ·add(SB), NOSPLIT, $0-24
	MOVQ a+0(FP), AX
	ADDQ b+8(FP), AX
	MOVQ AX, ret+16(FP)
	RET

// func sum(data []int64) int64
// Sums all elements of the slice.
TEXT ·sum(SB), NOSPLIT, $0-32
	MOVQ  data_base+0(FP), SI
	MOVQ  data_len+8(FP), CX
	XORQ  AX, AX
	TESTQ CX, CX
	JZ    sum_done

sum_loop:
	ADDQ  (SI), AX
	ADDQ  $8, SI
	DECQ  CX
	JNZ   sum_loop

sum_done:
	MOVQ  AX, ret+24(FP)
	RET

// func wideCopy(dst, src []byte)
// Non-overlapping copy of min(len(dst), len(src)) bytes using 32-byte moves.
TEXT ·wideCopy(SB), NOSPLIT, $0-48
	MOVQ       dst_base+0(FP), DI
	MOVQ       dst_len+8(FP), BX
	MOVQ       src_base+24(FP), SI
	MOVQ       src_len+32(FP), R8
	CMPQ       BX, R8
	JLE        wc_have_n
	MOVQ       R8, BX

wc_have_n:
	CMPQ       BX, $32
	JB         wc_small

	VMOVDQU    (SI), Y0
	VMOVDQU    Y0, (DI)
	VMOVDQU    -32(SI)(BX*1), Y0
	VMOVDQU    Y0,-32(DI)(BX*1)
	VZEROUPPER
	RET

wc_small:
	TESTQ      BX, BX
	JZ         wc_done

wc_byte:
	MOVB       (SI), R8B
	MOVB       R8B, (DI)
	INCQ       SI
	INCQ       DI
	DECQ       BX
	JNZ        wc_byte

wc_done:
	RET