1// Copyright 2021 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 goarch contains GOARCH-specific constants.
6package goarch
7
8// The next line makes 'go generate' write the zgoarch*.go files with
9// per-arch information, including constants named $GOARCH for every
10// GOARCH. The constant is 1 on the current system, 0 otherwise; multiplying
11// by them is useful for defining GOARCH-specific constants.
12//
13//go:generate go run gengoarch.go
14
15type ArchFamilyType int
16
17const (
18	AMD64 ArchFamilyType = iota
19	ARM
20	ARM64
21	I386
22	LOONG64
23	MIPS
24	MIPS64
25	PPC64
26	RISCV64
27	S390X
28	WASM
29)
30
31// PtrSize is the size of a pointer in bytes - unsafe.Sizeof(uintptr(0)) but as an ideal constant.
32// It is also the size of the machine's native word size (that is, 4 on 32-bit systems, 8 on 64-bit).
33const PtrSize = 4 << (^uintptr(0) >> 63)
34
35// ArchFamily is the architecture family (AMD64, ARM, ...)
36const ArchFamily ArchFamilyType = _ArchFamily
37
38// BigEndian reports whether the architecture is big-endian.
39const BigEndian = IsArmbe|IsArm64be|IsMips|IsMips64|IsPpc|IsPpc64|IsS390|IsS390x|IsSparc|IsSparc64 == 1
40
41// DefaultPhysPageSize is the default physical page size.
42const DefaultPhysPageSize = _DefaultPhysPageSize
43
44// PCQuantum is the minimal unit for a program counter (1 on x86, 4 on most other systems).
45// The various PC tables record PC deltas pre-divided by PCQuantum.
46const PCQuantum = _PCQuantum
47
48// Int64Align is the required alignment for a 64-bit integer (4 on 32-bit systems, 8 on 64-bit).
49const Int64Align = PtrSize
50
51// MinFrameSize is the size of the system-reserved words at the bottom
52// of a frame (just above the architectural stack pointer).
53// It is zero on x86 and PtrSize on most non-x86 (LR-based) systems.
54// On PowerPC it is larger, to cover three more reserved words:
55// the compiler word, the link editor word, and the TOC save word.
56const MinFrameSize = _MinFrameSize
57
58// StackAlign is the required alignment of the SP register.
59// The stack must be at least word aligned, but some architectures require more.
60const StackAlign = _StackAlign
61