OpenModem/bertos/emul/switch_x86_64.s

73 lines
2.5 KiB
ArmAsm

/**
* \file
* <!--
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* Copyright 2004, 2008 Develer S.r.l. (http://www.develer.com/)
* Copyright 1999, 2000, 2001 Bernie Innocenti <bernie@codewiz.org>
* -->
*
* \author Bernie Innocenti <bernie@codewiz.org>
*
* \brief x86_64 context switch
*
* x86_64 function call convention:
* --------------------------------
* arguments | callee-saved | extra caller-saved | return
* [callee-clobbered] | | [callee-clobbered] |
* -------------------------------------------------------------------------
* rdi rsi rdx rcx r8-9 | rbx rbp [*] r12-15 | r10-11 | rax, rdx
*
* [*] In the frame-pointers case rbp must hold a base address for the
* current stack frame.
*
* asm_switch_context() can be considered as a normal function call, so we need
* to save all the callee-clobbered registers minus the return registers.
*/
/* void asm_switch_context(void **new_sp [%rdi], void **save_sp [%rsi]) */
.globl asm_switch_context
asm_switch_context:
pushq %rbp
pushq %rdi
pushq %rsi
pushq %rcx
pushq %r8
pushq %r9
pushq %r10
pushq %r11
movq %rsp,(%rsi) /* *save_sp = rsp */
movq (%rdi),%rsp /* rsp = *new_sp */
popq %r11
popq %r10
popq %r9
popq %r8
popq %rcx
popq %rsi
popq %rdi
popq %rbp
ret