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

// Wide-immediate arithmetic: every classification band of the ADD/SUB
// immediate family (single imm12, the ADDCON2 split, bitmask and MOVZ/MOVN/
// MOVK materialisations into REGTMP) plus the logical bitmask immediates and
// their materialised fallback.  Byte-for-byte against go tool asm.

#include "textflag.h"

// imm12 covers the plain and shifted-by-12 imm12 forms.
TEXT ·imm12(SB), NOSPLIT, $0-0
	ADD  $1, R2, R3
	ADD  $0x000aaa, R2, R3
	ADD  $0xaaa000, R2
	SUB  $0x000aaa, R2, R3
	SUB  $0xaaa000, R2
	ADDW $40960, R0
	CMP  $40960, R0
	CMPW $40960, R0
	RET

// split pins the ADDCON2 band: two imm12 instructions, low half first.
TEXT ·split(SB), NOSPLIT, $0-0
	ADD  $0xaaaaaa, R2, R3
	SUB  $0xaaaaaa, R2
	ADD  $0x186a0, R2, R5
	SUB  $0x186a0, R2, R3
	ADDW $0x60060, R2
	RET

// regtmp covers the single-word materialisations: MOVZ for a movcon value,
// MOVN for the complement form, the bitmask ORR otherwise.
TEXT ·regtmp(SB), NOSPLIT, $0-0
	ADD $0x1ffe00, R2, R3
	ADD $0x3fffffffc000, R5
	ADD $-2048, R2, R3
	ADD $-100000, R2, R3
	CMP $0x1000000, R2
	CMP $0x100000000, R0
	SUB $-0x100000000, R0, R1
	RET

// movseq covers the omovlconst sequences: MOVZ/MOVN ladders and the
// compare forms that never split.
TEXT ·movseq(SB), NOSPLIT, $0-0
	ADD  $0x12345678, R2, R3
	SUB  $0xe7791f700, R3, R1
	CMP  $0xaaaaaa, R2
	CMP  $0xffffffffffa0, R3
	CMPW $27745, R2
	CMPW $0x60060, R2
	ADDS $0xaaaaaa, R2, R3
	CMN  $0x1000000, R2
	ADDW $0x12345678, R2, R3
	RET

// logical covers the bitmask immediates of the logical family and the
// materialised fallback for the values a bitmask cannot carry.
TEXT ·logical(SB), NOSPLIT, $0-0
	AND   $0x3ff00000, R2, R3
	BIC   $0x22220000, R3, R4
	ORR   $0x3ff00000, R2
	EOR   $0x3ff00000, R2, R3
	ANDS  $0x3ff00000, R2
	ORNW  $0x3ff00000, R2
	EONW  $0x3ff00000, R2
	BICSW $0x6006000060060, R5
	TST   $0x4900000049, R0
	RET