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// Copyright 2019 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.
// This provides a simplified version of getcontext and
// setcontext. They are like the corresponding functions
// in libc, but we only save/restore the callee-save
// registers and PC, SP. Unlike the libc functions, we
// don't save/restore the signal masks and floating point
// environment.
#if defined(__x86_64__) && defined(__linux__) && !defined(__CET__)
#define RBP_OFF (0*8)
#define RBX_OFF (1*8)
#define R12_OFF (2*8)
#define R13_OFF (3*8)
#define R14_OFF (4*8)
#define R15_OFF (5*8)
#define SP_OFF (6*8)
#define PC_OFF (7*8)
.globl __go_getcontext
.text
__go_getcontext:
movq %rbx, RBX_OFF(%rdi)
movq %rbp, RBP_OFF(%rdi)
movq %r12, R12_OFF(%rdi)
movq %r13, R13_OFF(%rdi)
movq %r14, R14_OFF(%rdi)
movq %r15, R15_OFF(%rdi)
movq (%rsp), %rax // return PC
movq %rax, PC_OFF(%rdi)
leaq 8(%rsp), %rax // the SP before pushing return PC
movq %rax, SP_OFF(%rdi)
ret
.globl __go_setcontext
.text
__go_setcontext:
movq RBX_OFF(%rdi), %rbx
movq RBP_OFF(%rdi), %rbp
movq R12_OFF(%rdi), %r12
movq R13_OFF(%rdi), %r13
movq R14_OFF(%rdi), %r14
movq R15_OFF(%rdi), %r15
movq SP_OFF(%rdi), %rsp
movq PC_OFF(%rdi), %rdx
jmp *%rdx
.globl __go_makecontext
.text
__go_makecontext:
addq %rcx, %rdx
// Align the SP, and push a dummy return address.
andq $~0xf, %rdx
subq $8, %rdx
movq $0, (%rdx)
movq %rdx, SP_OFF(%rdi)
movq %rsi, PC_OFF(%rdi)
ret
.section .note.GNU-split-stack,"",@progbits
.section .note.GNU-no-split-stack,"",@progbits
#endif
.section .note.GNU-stack,"",@progbits
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