m68k: add makecontext() implementation

pull/21/head
Ariadne Conill 2020-12-05 23:30:39 -06:00
parent 5ee9c4e8a5
commit 76f1fd75b8
1 changed files with 55 additions and 0 deletions

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arch/m68k/makecontext.c Normal file
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/*
* Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* This software is provided 'as is' and without any warranty, express or
* implied. In no event shall the authors be liable for any damages arising
* from the use of this software.
*/
#define _GNU_SOURCE
#include <stddef.h>
#include <stdarg.h>
#include <ucontext.h>
#include <string.h>
#include <stdint.h>
#include <stdio.h>
#include "defs.h"
extern void __start_context(void);
void
__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
{
greg_t *sp;
va_list va;
int i;
/* set up and align the stack. */
sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
sp -= (argc + 1);
sp = (greg_t *) (((uintptr_t) sp & ~0x3));
/* set up the ucontext structure */
ucp->uc_mcontext.gregs[REG_SP] = (greg_t) sp;
ucp->uc_mcontext.gregs[REG_A6] = 0;
/* return address */
*sp++ = (greg_t) __start_context;
va_start(va, argc);
/* all arguments overflow into stack */
for (i = 0; i < argc; i++)
*sp++ = va_arg (va, greg_t);
va_end(va);
}
extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext")));