[thirdparty/glibc.git] / sysdeps / powerpc / fpu / tst-setcontext-fpscr.c

/* Copyright (C) 2001,2002,2004,2006-2008,2009 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ryan S. Arnold <rsa@us.ibm.com>
                  Sean Curry <spcurry@us.ibm.com>

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ucontext.h>
#include <unistd.h>
#include <malloc.h>
#include <link.h>
#include <elf.h>
#include <sysdep.h>
#include <fpu_control.h>

static ucontext_t ctx[3];


volatile int global;


static int back_in_main;


volatile static ElfW(auxv_t) *auxv = NULL;

ElfW(Addr) query_auxv(int type)
{
  FILE *auxv_f;
  ElfW(auxv_t) auxv_struct;
  ElfW(auxv_t) *auxv_temp;
  int i = 0;

  /* if the /proc/self/auxv file has not been manually copied into the heap
     yet, then do it */

  if(auxv == NULL)
    {
      auxv_f = fopen("/proc/self/auxv", "r");

      if(auxv_f == 0)
	{
	  perror("Error opening file for reading");
	  return 0;
	}
      auxv = (ElfW(auxv_t) *)malloc(getpagesize());

      do
	{
	  fread(&auxv_struct, sizeof(ElfW(auxv_t)), 1, auxv_f);
	  auxv[i] = auxv_struct;
	  i++;
	} while(auxv_struct.a_type != AT_NULL);
    }

  auxv_temp = (ElfW(auxv_t) *)auxv;
  i = 0;
  do
    {
      if(auxv_temp[i].a_type == type)
	{
	  return auxv_temp[i].a_un.a_val;
	}
      i++;
    } while (auxv_temp[i].a_type != AT_NULL);

  return 0;
}

typedef unsigned long long di_fpscr_t __attribute__ ((__mode__ (__DI__)));
typedef unsigned int si_fpscr_t __attribute__ ((__mode__ (__SI__)));

#define _FPSCR_RESERVED 0xfffffff8ffffff04ULL

#define _FPSCR_TEST0_DRN 0x0000000400000000ULL
#define _FPSCR_TEST0_RN  0x0000000000000003ULL

#define _FPSCR_TEST1_DRN 0x0000000300000000ULL
#define _FPSCR_TEST1_RN  0x0000000000000002ULL

/* Macros for accessing the hardware control word on Power6[x].  */
# define _GET_DI_FPSCR(__fpscr) ({					     \
   union { double d;							     \
           di_fpscr_t fpscr; }						     \
     tmp __attribute__ ((__aligned__(8)));				     \
   __asm__ ("mffs 0; stfd%U0 0,%0" : "=m" (tmp.d) : : "fr0");		     \
   (__fpscr)=tmp.fpscr;							     \
   tmp.fpscr; })

/* We make sure to zero fp0 after we use it in order to prevent stale data
   in an fp register from making a test-case pass erroneously.  */
# define _SET_DI_FPSCR(__fpscr) {					     \
  union { double d; di_fpscr_t fpscr; }					     \
    tmp __attribute__ ((__aligned__(8)));				     \
  tmp.fpscr = __fpscr;							     \
  /* Set the entire 64-bit FPSCR.  */					     \
  __asm__ ("lfd%U0 0,%0; "						     \
	   ".machine push; "						     \
	   ".machine \"power6\"; "					     \
	   "mtfsf 255,0,1,0; "						     \
	   ".machine pop" : : "m" (tmp.d) : "fr0");			     \
  tmp.d = 0;								     \
  __asm__("lfd%U0 0,%0" : : "m" (tmp.d) : "fr0");			     \
}

# define _GET_SI_FPSCR(__fpscr) ({					     \
   union { double d;							     \
           si_fpscr_t cw[2]; }						     \
     tmp __attribute__ ((__aligned__(8)));				     \
   __asm__ ("mffs 0; stfd%U0 0,%0" : "=m" (tmp.d) : : "fr0");		     \
   (__fpscr)=tmp.cw[1];							     \
   tmp.cw[0]; })

/* We make sure to zero fp0 after we use it in order to prevent stale data
   in an fp register from making a test-case pass erroneously.  */
# define _SET_SI_FPSCR(__fpscr) {					     \
  union { double d; si_fpscr_t fpscr[2]; }				     \
    tmp __attribute__ ((__aligned__(8)));				     \
  /* More-or-less arbitrary; this is a QNaN. */				     \
  tmp.fpscr[0] = 0xFFF80000;						     \
  tmp.fpscr[1] = __fpscr;						     \
  __asm__ ("lfd%U0 0,%0; mtfsf 255,0" : : "m" (tmp.d) : "fr0");		     \
  tmp.d = 0;								     \
  __asm__("lfd%U0 0,%0" : : "m" (tmp.d) : "fr0");			     \
}

void prime_special_regs(int which)
{
  ElfW(Addr) a_val;

  di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));

  a_val = query_auxv(AT_HWCAP);
  if(a_val == -1)
    {
      puts ("querying the auxv for the hwcap failed");
      _exit (1);
    }

  /* Indicates a 64-bit FPSCR.  */
  if (a_val & PPC_FEATURE_HAS_DFP)
    {
      _GET_DI_FPSCR(di_fpscr);

      /* Overwrite the existing DRN and RN if there is one.  */
      if (which == 0)
        di_fpscr = ((di_fpscr & _FPSCR_RESERVED) | (_FPSCR_TEST0_DRN | _FPSCR_TEST0_RN));
      else
        di_fpscr = ((di_fpscr & _FPSCR_RESERVED) | (_FPSCR_TEST1_DRN | _FPSCR_TEST1_RN));
      puts ("Priming 64-bit FPSCR with:");
      printf("0x%.16llx\n",(unsigned long long int)di_fpscr);

      _SET_DI_FPSCR(di_fpscr);
    }
  else
    {
      puts ("32-bit FPSCR found and will be tested.");
      _GET_SI_FPSCR(di_fpscr);

      /* Overwrite the existing RN if there is one.  */
      if (which == 0)
        di_fpscr = ((di_fpscr & _FPSCR_RESERVED) | (_FPSCR_TEST0_RN));
      else
        di_fpscr = ((di_fpscr & _FPSCR_RESERVED) | (_FPSCR_TEST1_RN));
      puts ("Priming 32-bit FPSCR with:");
      printf("0x%.8lx\n",(unsigned long int) di_fpscr);

      _SET_SI_FPSCR(di_fpscr);
    }
}

void clear_special_regs(void)
{
  ElfW(Addr) a_val;

  di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));

  union {
	  double d;
	  unsigned long long int lli;
	  unsigned int li[2];
  } dlli;

  a_val = query_auxv(AT_HWCAP);
  if(a_val == -1)
    {
      puts ("querying the auxv for the hwcap failed");
      _exit (1);
    }

#if __WORDSIZE == 32
  dlli.d = ctx[0].uc_mcontext.uc_regs->fpregs.fpscr;
#else
  dlli.d = ctx[0].uc_mcontext.fp_regs[32];
#endif

  puts("The FPSCR value saved in the ucontext_t is:");

  /* Indicates a 64-bit FPSCR.  */
  if (a_val & PPC_FEATURE_HAS_DFP)
    {
      printf("0x%.16llx\n",dlli.lli);
      di_fpscr = 0x0;
      puts ("Clearing the 64-bit FPSCR to:");
      printf("0x%.16llx\n",(unsigned long long int) di_fpscr);

      _SET_DI_FPSCR(di_fpscr);
    }
  else
    {
      printf("0x%.8x\n",(unsigned int) dlli.li[1]);
      di_fpscr = 0x0;
      puts ("Clearing the 32-bit FPSCR to:");
      printf("0x%.8lx\n",(unsigned long int) di_fpscr);

      _SET_SI_FPSCR(di_fpscr);
    }
}

void test_special_regs(int which)
{
  ElfW(Addr) a_val;
  unsigned long long int test;

  di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));

  a_val = query_auxv(AT_HWCAP);
  if(a_val == -1)
    {
      puts ("querying the auxv for the hwcap failed");
      _exit (2);
    }

  /* Indicates a 64-bit FPSCR.  */
  if (a_val & PPC_FEATURE_HAS_DFP)
    {
      _GET_DI_FPSCR(di_fpscr);

      if (which == 0)
	puts ("After setcontext the 64-bit FPSCR contains:");
      else
	puts ("After swapcontext the 64-bit FPSCR contains:");

      printf("0x%.16llx\n",(unsigned long long int) di_fpscr);
      test = (_FPSCR_TEST0_DRN | _FPSCR_TEST0_RN);
      if((di_fpscr & (test)) != (test))
        {
	  printf ("%s: DRN and RN bits set before getcontext were not preserved across [set|swap]context call: %m",__FUNCTION__);
	  _exit (3);
        }
    }
  else
    {
      _GET_SI_FPSCR(di_fpscr);
      if (which == 0)
	puts ("After setcontext the 32-bit FPSCR contains:");
      else
	puts ("After swapcontext the 32-bit FPSCR contains:");

      printf("0x%.8lx\n",(unsigned long int) di_fpscr);
      test = _FPSCR_TEST0_RN;
      if((di_fpscr & test) != test)
        {
	  printf ("%s: RN bit set before getcontext was not preserved across [set|swap]context call: %m",__FUNCTION__);
	  _exit (4);
        }
    }
}


static void
check_called (void)
{
  if (back_in_main == 0)
    {
      puts ("program did not reach main again");
      _exit (5);
    }
}


int
main (void)
{
  atexit (check_called);

  puts ("priming the FPSCR with a marker");
  prime_special_regs (0);

  puts ("making contexts");
  if (getcontext (&ctx[0]) != 0)
    {
      if (errno == ENOSYS)
	{
	  back_in_main = 1;
	  exit (0);
	}

      printf ("%s: getcontext: %m\n", __FUNCTION__);
      exit (6);
    }

  /* Play some tricks with this context.  */
  if (++global == 1)
    {
    clear_special_regs ( );
    if (setcontext (&ctx[0]) != 0)
      {
	printf ("%s: setcontext: %m\n", __FUNCTION__);
	exit (7);
      }
    }
  if (global != 2)
    {
      printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
      exit (8);
    }

  test_special_regs (0);

  global = 0;
  if (getcontext (&ctx[0]) != 0)
    {
      printf ("%s: getcontext: %m\n", __FUNCTION__);
      exit (9);
    }

  if (++global == 1)
    {
      puts ("priming the FPSCR with a marker");
      prime_special_regs (1);

      puts ("swapping contexts");
      if (swapcontext (&ctx[1], &ctx[0]) != 0)
        {
          printf ("%s: swapcontext: %m\n", __FUNCTION__);
          exit (9);
        }
    }
  if (global != 2)
    {
      printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
      exit (10);
    }

  test_special_regs (1);

  puts ("back at main program");
  back_in_main = 1;

  puts ("test succeeded");
  return 0;
}
Commit	Line	Data
b7219e53	1	/* Copyright (C) 2001,2002,2004,2006-2008,2009 Free Software Foundation, Inc.
edba7a54 UD	2	This file is part of the GNU C Library.
	3	Contributed by Ryan S. Arnold <rsa@us.ibm.com>
	4	Sean Curry <spcurry@us.ibm.com>
	5
	6	The GNU C Library is free software; you can redistribute it and/or
	7	modify it under the terms of the GNU Lesser General Public
	8	License as published by the Free Software Foundation; either
	9	version 2.1 of the License, or (at your option) any later version.
	10
	11	The GNU C Library is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	Lesser General Public License for more details.
	15
	16	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	17	License along with the GNU C Library; if not, see
59ba27a6 PE	18	<http://www.gnu.org/licenses/>. */
edba7a54 UD	19
	20	#include <errno.h>
	21	#include <stdio.h>
	22	#include <stdlib.h>
	23	#include <string.h>
	24	#include <ucontext.h>
	25	#include <unistd.h>
	26	#include <malloc.h>
	27	#include <link.h>
	28	#include <elf.h>
	29	#include <sysdep.h>
	30	#include <fpu_control.h>
	31
	32	static ucontext_t ctx[3];
	33
	34
	35	volatile int global;
	36
	37
	38	static int back_in_main;
	39
	40
	41	volatile static ElfW(auxv_t) *auxv = NULL;
	42
	43	ElfW(Addr) query_auxv(int type)
	44	{
	45	FILE *auxv_f;
	46	ElfW(auxv_t) auxv_struct;
	47	ElfW(auxv_t) *auxv_temp;
	48	int i = 0;
	49
	50	/* if the /proc/self/auxv file has not been manually copied into the heap
	51	yet, then do it */
	52
	53	if(auxv == NULL)
	54	{
	55	auxv_f = fopen("/proc/self/auxv", "r");
	56
	57	if(auxv_f == 0)
	58	{
	59	perror("Error opening file for reading");
	60	return 0;
	61	}
	62	auxv = (ElfW(auxv_t) *)malloc(getpagesize());
	63
	64	do
	65	{
	66	fread(&auxv_struct, sizeof(ElfW(auxv_t)), 1, auxv_f);
	67	auxv[i] = auxv_struct;
	68	i++;
	69	} while(auxv_struct.a_type != AT_NULL);
	70	}
	71
	72	auxv_temp = (ElfW(auxv_t) *)auxv;
	73	i = 0;
	74	do
	75	{
	76	if(auxv_temp[i].a_type == type)
	77	{
	78	return auxv_temp[i].a_un.a_val;
	79	}
	80	i++;
	81	} while (auxv_temp[i].a_type != AT_NULL);
	82
83	return 0;
84	}
85
86	typedef unsigned long long di_fpscr_t __attribute__ ((__mode__ (__DI__)));
87	typedef unsigned int si_fpscr_t __attribute__ ((__mode__ (__SI__)));
88
89	#define _FPSCR_RESERVED 0xfffffff8ffffff04ULL
90
91	#define _FPSCR_TEST0_DRN 0x0000000400000000ULL
92	#define _FPSCR_TEST0_RN 0x0000000000000003ULL
93
94	#define _FPSCR_TEST1_DRN 0x0000000300000000ULL
95	#define _FPSCR_TEST1_RN 0x0000000000000002ULL
96
97	/* Macros for accessing the hardware control word on Power6[x]. */
98	# define _GET_DI_FPSCR(__fpscr) ({ \
99	union { double d; \
100	di_fpscr_t fpscr; } \
101	tmp __attribute__ ((__aligned__(8))); \
102	__asm__ ("mffs 0; stfd%U0 0,%0" : "=m" (tmp.d) : : "fr0"); \
103	(__fpscr)=tmp.fpscr; \
104	tmp.fpscr; })
105
b7219e53 UD	106	/* We make sure to zero fp0 after we use it in order to prevent stale data
b7219e53 UD	107	in an fp register from making a test-case pass erroneously. */
edba7a54 UD	108	# define _SET_DI_FPSCR(__fpscr) { \
	109	union { double d; di_fpscr_t fpscr; } \
	110	tmp __attribute__ ((__aligned__(8))); \
	111	tmp.fpscr = __fpscr; \
	112	/* Set the entire 64-bit FPSCR. */ \
1454da21 UD	113	__asm__ ("lfd%U0 0,%0; " \
	114	".machine push; " \
	115	".machine \"power6\"; " \
	116	"mtfsf 255,0,1,0; " \
	117	".machine pop" : : "m" (tmp.d) : "fr0"); \
b7219e53 UD	118	tmp.d = 0; \
b7219e53 UD	119	__asm__("lfd%U0 0,%0" : : "m" (tmp.d) : "fr0"); \
edba7a54 UD	120	}
	121
	122	# define _GET_SI_FPSCR(__fpscr) ({ \
	123	union { double d; \
	124	si_fpscr_t cw[2]; } \
	125	tmp __attribute__ ((__aligned__(8))); \
	126	__asm__ ("mffs 0; stfd%U0 0,%0" : "=m" (tmp.d) : : "fr0"); \
	127	(__fpscr)=tmp.cw[1]; \
	128	tmp.cw[0]; })
	129
b7219e53 UD	130	/* We make sure to zero fp0 after we use it in order to prevent stale data
b7219e53 UD	131	in an fp register from making a test-case pass erroneously. */
edba7a54 UD	132	# define _SET_SI_FPSCR(__fpscr) { \
	133	union { double d; si_fpscr_t fpscr[2]; } \
	134	tmp __attribute__ ((__aligned__(8))); \
	135	/* More-or-less arbitrary; this is a QNaN. */ \
	136	tmp.fpscr[0] = 0xFFF80000; \
	137	tmp.fpscr[1] = __fpscr; \
	138	__asm__ ("lfd%U0 0,%0; mtfsf 255,0" : : "m" (tmp.d) : "fr0"); \
b7219e53 UD	139	tmp.d = 0; \
b7219e53 UD	140	__asm__("lfd%U0 0,%0" : : "m" (tmp.d) : "fr0"); \
edba7a54 UD	141	}
	142
	143	void prime_special_regs(int which)
	144	{
	145	ElfW(Addr) a_val;
	146
	147	di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));
	148
	149	a_val = query_auxv(AT_HWCAP);
	150	if(a_val == -1)
	151	{
	152	puts ("querying the auxv for the hwcap failed");
	153	_exit (1);
	154	}
	155
	156	/* Indicates a 64-bit FPSCR. */
	157	if (a_val & PPC_FEATURE_HAS_DFP)
	158	{
	159	_GET_DI_FPSCR(di_fpscr);
	160
	161	/* Overwrite the existing DRN and RN if there is one. */
	162	if (which == 0)
	163	di_fpscr = ((di_fpscr & _FPSCR_RESERVED) \| (_FPSCR_TEST0_DRN \| _FPSCR_TEST0_RN));
	164	else
	165	di_fpscr = ((di_fpscr & _FPSCR_RESERVED) \| (_FPSCR_TEST1_DRN \| _FPSCR_TEST1_RN));
	166	puts ("Priming 64-bit FPSCR with:");
	167	printf("0x%.16llx\n",(unsigned long long int)di_fpscr);
	168
	169	_SET_DI_FPSCR(di_fpscr);
	170	}
	171	else
	172	{
	173	puts ("32-bit FPSCR found and will be tested.");
	174	_GET_SI_FPSCR(di_fpscr);
	175
	176	/* Overwrite the existing RN if there is one. */
	177	if (which == 0)
	178	di_fpscr = ((di_fpscr & _FPSCR_RESERVED) \| (_FPSCR_TEST0_RN));
	179	else
	180	di_fpscr = ((di_fpscr & _FPSCR_RESERVED) \| (_FPSCR_TEST1_RN));
	181	puts ("Priming 32-bit FPSCR with:");
	182	printf("0x%.8lx\n",(unsigned long int) di_fpscr);
	183
	184	_SET_SI_FPSCR(di_fpscr);
	185	}
	186	}
	187
	188	void clear_special_regs(void)
	189	{
	190	ElfW(Addr) a_val;
	191
	192	di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));
	193
	194	union {
	195	double d;
	196	unsigned long long int lli;
	197	unsigned int li[2];
	198	} dlli;
	199
	200	a_val = query_auxv(AT_HWCAP);
	201	if(a_val == -1)
	202	{
	203	puts ("querying the auxv for the hwcap failed");
	204	_exit (1);
205	}
206
207	#if __WORDSIZE == 32
208	dlli.d = ctx[0].uc_mcontext.uc_regs->fpregs.fpscr;
209	#else
210	dlli.d = ctx[0].uc_mcontext.fp_regs[32];
211	#endif
212
213	puts("The FPSCR value saved in the ucontext_t is:");
214
215	/* Indicates a 64-bit FPSCR. */
216	if (a_val & PPC_FEATURE_HAS_DFP)
217	{
218	printf("0x%.16llx\n",dlli.lli);
219	di_fpscr = 0x0;
220	puts ("Clearing the 64-bit FPSCR to:");
221	printf("0x%.16llx\n",(unsigned long long int) di_fpscr);
222
223	_SET_DI_FPSCR(di_fpscr);
224	}
225	else
226	{
227	printf("0x%.8x\n",(unsigned int) dlli.li[1]);
228	di_fpscr = 0x0;
229	puts ("Clearing the 32-bit FPSCR to:");
230	printf("0x%.8lx\n",(unsigned long int) di_fpscr);
231
232	_SET_SI_FPSCR(di_fpscr);
233	}
234	}
235
236	void test_special_regs(int which)
237	{
238	ElfW(Addr) a_val;
239	unsigned long long int test;
240
241	di_fpscr_t di_fpscr __attribute__ ((__aligned__(8)));
242
243	a_val = query_auxv(AT_HWCAP);
244	if(a_val == -1)
245	{
246	puts ("querying the auxv for the hwcap failed");
247	_exit (2);
248	}
249
250	/* Indicates a 64-bit FPSCR. */
251	if (a_val & PPC_FEATURE_HAS_DFP)
252	{
253	_GET_DI_FPSCR(di_fpscr);
254
255	if (which == 0)
256	puts ("After setcontext the 64-bit FPSCR contains:");
257	else
258	puts ("After swapcontext the 64-bit FPSCR contains:");
259
260	printf("0x%.16llx\n",(unsigned long long int) di_fpscr);
261	test = (_FPSCR_TEST0_DRN \| _FPSCR_TEST0_RN);
262	if((di_fpscr & (test)) != (test))
263	{
264	printf ("%s: DRN and RN bits set before getcontext were not preserved across [set\|swap]context call: %m",__FUNCTION__);
265	_exit (3);
266	}
267	}
268	else
269	{
270	_GET_SI_FPSCR(di_fpscr);
271	if (which == 0)
272	puts ("After setcontext the 32-bit FPSCR contains:");
273	else
274	puts ("After swapcontext the 32-bit FPSCR contains:");
275
276	printf("0x%.8lx\n",(unsigned long int) di_fpscr);
277	test = _FPSCR_TEST0_RN;
278	if((di_fpscr & test) != test)
279	{
280	printf ("%s: RN bit set before getcontext was not preserved across [set\|swap]context call: %m",__FUNCTION__);
281	_exit (4);
282	}
283	}
284	}
285
286
287	static void
288	check_called (void)
289	{
290	if (back_in_main == 0)
291	{
292	puts ("program did not reach main again");
293	_exit (5);
294	}
295	}
296
297
298	int
299	main (void)
300	{
301	atexit (check_called);
302
303	puts ("priming the FPSCR with a marker");
304	prime_special_regs (0);
305
306	puts ("making contexts");
307	if (getcontext (&ctx[0]) != 0)
308	{
309	if (errno == ENOSYS)
310	{
311	back_in_main = 1;
312	exit (0);
313	}
314
315	printf ("%s: getcontext: %m\n", __FUNCTION__);
316	exit (6);
317	}
318
319	/* Play some tricks with this context. */
320	if (++global == 1)
321	{
322	clear_special_regs ( );
323	if (setcontext (&ctx[0]) != 0)
324	{
325	printf ("%s: setcontext: %m\n", __FUNCTION__);
326	exit (7);
327	}
328	}
329	if (global != 2)
330	{
331	printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
332	exit (8);
333	}
334
335	test_special_regs (0);
336
337	global = 0;
338	if (getcontext (&ctx[0]) != 0)
339	{
340	printf ("%s: getcontext: %m\n", __FUNCTION__);
341	exit (9);
342	}
343
344	if (++global == 1)
345	{
346	puts ("priming the FPSCR with a marker");
347	prime_special_regs (1);
348
349	puts ("swapping contexts");
350	if (swapcontext (&ctx[1], &ctx[0]) != 0)
351	{
352	printf ("%s: swapcontext: %m\n", __FUNCTION__);
353	exit (9);
354	}
355	}
356	if (global != 2)
357	{
358	printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
359	exit (10);
360	}
361
362	test_special_regs (1);
363
364	puts ("back at main program");
365	back_in_main = 1;
366
367	puts ("test succeeded");
368	return 0;
369	}