| // Copyright 2015 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // FIXED_FRAME defines the size of the fixed part of a stack frame. A stack |
| // frame looks like this: |
| // |
| // +---------------------+ |
| // | local variable area | |
| // +---------------------+ |
| // | argument area | |
| // +---------------------+ <- R1+FIXED_FRAME |
| // | fixed area | |
| // +---------------------+ <- R1 |
| // |
| // So a function that sets up a stack frame at all uses as least FIXED_FRAME |
| // bytes of stack. This mostly affects assembly that calls other functions |
| // with arguments (the arguments should be stored at FIXED_FRAME+0(R1), |
| // FIXED_FRAME+8(R1) etc) and some other low-level places. |
| // |
| // The reason for using a constant is to make supporting PIC easier (although |
| // we only support PIC on ppc64le which has a minimum 32 bytes of stack frame, |
| // and currently always use that much, PIC on ppc64 would need to use 48). |
| |
| #define FIXED_FRAME 32 |
