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/* $OpenBSD: uthread_machdep.c,v 1.3 2003/01/24 20:58:23 marc Exp $ */
/* David Leonard, <d@csee.uq.edu.au>. Public domain. */
/*
* Machine-dependent thread state functions for OpenBSD/i386.
*/
#include <machine/param.h>
#include <pthread.h>
#include "pthread_private.h"
struct frame {
int fr_gs;
int fr_fs;
int fr_es;
int fr_ds;
int fr_edi;
int fr_esi;
int fr_ebp;
int fr_esp;
int fr_ebx;
int fr_edx;
int fr_ecx;
int fr_eax;
int fr_eip;
int fr_cs; /* XXX unreachable? */
};
#define copyreg(reg, lval) \
__asm__("mov %%" #reg ", %0" : "=g"(lval))
/*
* Given a stack and an entry function, initialise a state
* structure that can be later switched to.
*/
void
_thread_machdep_init(struct _machdep_state* statep, void *base, int len,
void (*entry)(void))
{
struct frame *f;
/* Locate the initial frame, aligned at the top of the stack */
f = (struct frame *)(((int)base + len - sizeof *f) & ~ALIGNBYTES);
/* Set up initial frame */
f->fr_esp = (int)&f->fr_edi;
copyreg(cs, f->fr_cs);
copyreg(ds, f->fr_ds);
copyreg(es, f->fr_es);
copyreg(fs, f->fr_fs);
copyreg(gs, f->fr_gs);
f->fr_ebp = (int)-1;
f->fr_eip = (int)entry;
statep->esp = (int)f;
_thread_machdep_save_float_state(statep);
}
/*
* Floating point save restore copied from code in npx.c
* (without really understanding what it does).
*/
#define fldcw(addr) __asm("fldcw %0" : : "m" (*addr))
#define fnsave(addr) __asm("fnsave %0" : "=m" (*addr))
#define frstor(addr) __asm("frstor %0" : : "m" (*addr))
#define fwait() __asm("fwait")
void
_thread_machdep_save_float_state(struct _machdep_state *ms)
{
struct save87 *addr = &ms->fpreg;
fnsave(addr);
fwait();
}
void
_thread_machdep_restore_float_state(struct _machdep_state *ms)
{
struct save87 *addr = &ms->fpreg;
frstor(addr);
}
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