1 // Copyright 2017 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 arm64asm 6 7 func extract_bit(value, bit uint32) uint32 { 8 return (value >> bit) & 1 9 } 10 11 func bfxpreferred_4(sf, opc1, imms, immr uint32) bool { 12 if imms < immr { 13 return false 14 } 15 if (imms>>5 == sf) && (imms&0x1f == 0x1f) { 16 return false 17 } 18 if immr == 0 { 19 if sf == 0 && (imms == 7 || imms == 15) { 20 return false 21 } 22 if sf == 1 && opc1 == 0 && (imms == 7 || 23 imms == 15 || imms == 31) { 24 return false 25 } 26 } 27 return true 28 } 29 30 func move_wide_preferred_4(sf, N, imms, immr uint32) bool { 31 if sf == 1 && N != 1 { 32 return false 33 } 34 if sf == 0 && !(N == 0 && ((imms>>5)&1) == 0) { 35 return false 36 } 37 if imms < 16 { 38 return (-immr)%16 <= (15 - imms) 39 } 40 width := uint32(32) 41 if sf == 1 { 42 width = uint32(64) 43 } 44 if imms >= (width - 15) { 45 return (immr % 16) <= (imms - (width - 15)) 46 } 47 return false 48 } 49 50 type Sys uint8 51 52 const ( 53 Sys_AT Sys = iota 54 Sys_DC 55 Sys_IC 56 Sys_TLBI 57 Sys_SYS 58 ) 59 60 func sys_op_4(op1, crn, crm, op2 uint32) Sys { 61 // TODO: system instruction 62 return Sys_SYS 63 } 64 65 func is_zero(x uint32) bool { 66 return x == 0 67 } 68 69 func is_ones_n16(x uint32) bool { 70 return x == 0xffff 71 } 72 73 func bit_count(x uint32) uint8 { 74 var count uint8 75 for count = 0; x > 0; x >>= 1 { 76 if (x & 1) == 1 { 77 count++ 78 } 79 } 80 return count 81 } 82
