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

#include "textflag.h"

// Index vector for the order-2 ramp.
GLOBL ·idx16(SB), RODATA, $64
DATA ·idx16+0(SB)/4, $1
DATA ·idx16+4(SB)/4, $2

// A file-local (static) constant table.
GLOBL mask24<>(SB), RODATA, $16
DATA mask24<>+0(SB)/4, $0x80020100
DATA mask24<>+4(SB)/4, $0x80050403

// func analyzeO1RangeAVX2(swin []int32, dstP []uint32, hist *[32]uint16) (partSum uint64, overflow bool)
TEXT ·analyzeO1RangeAVX2(SB), NOSPLIT, $0-65
	MOVQ swin_base+0(FP), SI
	MOVQ dstP_base+24(FP), DI
	MOVQ dstP_len+32(FP), BX
	MOVQ hist+48(FP), R13

	VPCMPEQD Y0, Y0, Y0
	VPSLLD   $31, Y0, Y0

	LEAQ (SI)(BX*4), R9
	MOVQ BX, R10
	ANDQ $-8, R10

vec1:
	CMPQ    SI, R10
	JGE     vec1done
	VMOVDQU (SI), Y1
	VMOVDQU 4(SI), Y2
	VPSUBD  Y1, Y2, Y3
	ADDQ    $32, SI
	JMP     vec1
vec1done:

	MOVQ AX, partSum+56(FP)
	MOVB AL, overflow+64(FP)
	VZEROUPPER
	RET

// func decodeFixedO1AVX512(samples []int32, residual []int32)
TEXT ·decodeFixedO1AVX512(SB), NOSPLIT, $0-48
	MOVQ samples_base+0(FP), SI
	VPBROADCASTD AX, Z15
	VMOVDQU32 (DI)(AX*1), Z0
	VALIGND   $15, Z9, Z0, Z1
	VFMADD231PD Z14, Z12, Z10
	VPCMPEQD  Z0, Z3, K1
	KTESTW    K1, K1
	VPSRAQ    X31, Z8, Z8
	VMOVDQU32 Z0, 4(SI)(AX*1)
	RET