#include "textflag.h"

// func getisar0() uint64
TEXT ·getisar0(SB),NOSPLIT,$0
	// get Instruction Set Attributes 0 into R0
	MRS	ID_AA64ISAR0_EL1, R0
	MOVD	R0, ret+0(FP)
	RET

// func getMIDR() uint64
TEXT ·getMIDR(SB), NOSPLIT, $0-8
	MRS	MIDR_EL1, R0
	MOVD	R0, ret+0(FP)

	// check the AUXV for the CPUID bit. The getMIDR function executes an
	// instruction which would normally be an illegal instruction, but it's
	// trapped by the kernel, the value sanitized and then returned.
	// Without the CPUID bit the kernel will not trap the instruction and the
	// process will be terminated with SIGILL.
	if ARM64.HasCPUID {
		midr := getMIDR()
		part_num := uint16((midr >> 4) & 0xfff)

		{Name: "isNeoverse", Feature: &ARM64.IsNeoverse},
	}

	// arm64 uses different ways to detect CPU features at runtime depending on the operating system.
	osInit()
}

func getisar0() uint64

func getMIDR() uint64

func extractBits(data uint64, start, end uint) uint {
	return (uint)(data>>start) & ((1 << (end - start + 1)) - 1)
}

func parseARM64SystemRegisters(isar0 uint64) {
	// ID_AA64ISAR0_EL1