1 // Copyright 2016 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package runtime 6 7 import ( 8 "runtime/internal/sys" 9 ) 10 11 const ( 12 // bit masks taken from bits/hwcap.h 13 _HWCAP_S390_VX = 2048 // vector facility 14 ) 15 16 // facilities is padded to avoid false sharing. 17 type facilities struct { 18 _ [sys.CacheLineSize]byte 19 hasVX bool // vector facility 20 _ [sys.CacheLineSize]byte 21 } 22 23 // cpu indicates the availability of s390x facilities that can be used in 24 // Go assembly but are optional on models supported by Go. 25 var cpu facilities 26 27 func archauxv(tag, val uintptr) { 28 switch tag { 29 case _AT_HWCAP: // CPU capability bit flags 30 cpu.hasVX = val&_HWCAP_S390_VX != 0 31 } 32 } 33
