1 // Copyright 2014 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 sys
6 7 import (
8 "internal/goarch"
9 "internal/goos"
10 )
11 12 // AIX and OpenBSD require a larger stack for syscalls.
13 // The race build also needs more stack. See issue 54291.
14 // This arithmetic must match that in cmd/internal/objabi/stack.go:stackGuardMultiplier.
15 const StackGuardMultiplier = 1 + goos.IsAix + goos.IsOpenbsd + isRace
16 17 // DefaultPhysPageSize is the default physical page size.
18 const DefaultPhysPageSize = goarch.DefaultPhysPageSize
19 20 // PCQuantum is the minimal unit for a program counter (1 on x86, 4 on most other systems).
21 // The various PC tables record PC deltas pre-divided by PCQuantum.
22 const PCQuantum = goarch.PCQuantum
23 24 // Int64Align is the required alignment for a 64-bit integer (4 on 32-bit systems, 8 on 64-bit).
25 const Int64Align = goarch.PtrSize
26 27 // MinFrameSize is the size of the system-reserved words at the bottom
28 // of a frame (just above the architectural stack pointer).
29 // It is zero on x86 and PtrSize on most non-x86 (LR-based) systems.
30 // On PowerPC it is larger, to cover three more reserved words:
31 // the compiler word, the link editor word, and the TOC save word.
32 const MinFrameSize = goarch.MinFrameSize
33 34 // StackAlign is the required alignment of the SP register.
35 // The stack must be at least word aligned, but some architectures require more.
36 const StackAlign = goarch.StackAlign
37